From 89fc1cbdc5842dde0bdbc2e4e2f2929e59fc4302 Mon Sep 17 00:00:00 2001
From: DeepZone <mail@noisens.de>
Date: Wed, 20 May 2026 15:45:37 +0100
Subject: [PATCH] Add RIPEstat retry resilience, fallback diagnostics, and
 v0.4.2-alpha bump

---
 .env.example                             |   5 +
 README.md                                |  18 +-
 RELEASE_NOTES.md                         |  13 ++
 backend/app/api/routes_system.py         |   2 +-
 backend/app/config.py                    |   4 +
 backend/app/core/source_diagnostics.py   |  10 +
 backend/app/main.py                      |   2 +-
 backend/app/services/ripe_stat_client.py | 266 +++++++++++------------
 backend/app/templates/report.html.j2     |   2 +-
 backend/app/templates/report.md.j2       |   4 +-
 backend/pyproject.toml                   |   2 +-
 backend/tests/test_api_smoke.py          |   6 +-
 backend/tests/test_ripe_stat_client.py   |  75 +++++--
 backend/tests/test_source_diagnostics.py |   8 +
 frontend/package-lock.json               |   4 +-
 frontend/package.json                    |   2 +-
 frontend/src/App.tsx                     |   6 +-
 frontend/src/components/Layout.tsx       |   2 +-
 frontend/src/components/ReportView.tsx   |   2 +-
 frontend/src/types.ts                    |   5 +
 20 files changed, 266 insertions(+), 172 deletions(-)

diff --git a/.env.example b/.env.example
index 18deb2c..1b7298c 100644
--- a/.env.example
+++ b/.env.example
@@ -6,3 +6,8 @@ CORS_ORIGINS=http://localhost:3000,http://127.0.0.1:3000
 RIPESTAT_BASE_URL=https://stat.ripe.net/data
 ROUTEFORGE_DEMO_MODE=false
 VITE_API_URL=http://localhost:8000
+
+RIPESTAT_TIMEOUT_SECONDS=10
+RIPESTAT_MAX_RETRIES=1
+RIPESTAT_RETRY_BACKOFF_SECONDS=0.5
+RIPESTAT_USE_STALE_CACHE_ON_ERROR=true
diff --git a/README.md b/README.md
index 932fb58..4d7fbc9 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 RouteForge is a read-only routing preflight and explainability tool for BGP, RPKI, Registry/IRR and Routing Visibility checks.
 
-Current user-facing version: **v0.4.1-alpha**.
+Current user-facing version: **v0.4.2-alpha**.
 
 <!-- Screenshot gallery placeholder:
 - docs/screenshots/dashboard.png
@@ -32,7 +32,7 @@ Routing changes often require fast but traceable checks across multiple external
 
 ## Current Alpha Status
 
-RouteForge is a **functional alpha** release with production-like workflows for read-only validation and demo usage. Current release target: **v0.4.1-alpha**.
+RouteForge is a **functional alpha** release with production-like workflows for read-only validation and demo usage. Current release target: **v0.4.2-alpha**.
 
 ## Quickstart with Docker Compose
 
@@ -96,6 +96,20 @@ Preflight decision model:
 
 ## Cache and Freshness
 
+
+## Retry and Resilience
+
+RouteForge retries temporary RIPEstat failures with configurable timeout/retry settings and exposes attempt/retry diagnostics in Data Source Diagnostics.
+
+When stale-cache fallback is enabled, RouteForge can use stale cached data if the live request fails, and explicitly marks this in diagnostics and reports.
+
+Configuration:
+- `RIPESTAT_TIMEOUT_SECONDS`
+- `RIPESTAT_MAX_RETRIES`
+- `RIPESTAT_RETRY_BACKOFF_SECONDS`
+- `RIPESTAT_USE_STALE_CACHE_ON_ERROR`
+
+
 RouteForge shows per-source diagnostics indicating whether data was fetched live or served from cache. Cache Age, TTL and Freshness help operators assess how current a result is.
 
 Freshness values:
diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index fb69802..c39ba60 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -1,5 +1,18 @@
 # Release Notes
 
+## v0.4.2-alpha
+
+### Highlights
+
+- Retry & Resilience
+- Retry diagnostics
+- Attempts/retry count visible
+- Rate-limit handling
+- Optional stale cache fallback
+- UI/report warning when fallback data is used
+
+---
+
 ## v0.4.1-alpha
 
 ### Highlights
diff --git a/backend/app/api/routes_system.py b/backend/app/api/routes_system.py
index 71650ac..90239fd 100644
--- a/backend/app/api/routes_system.py
+++ b/backend/app/api/routes_system.py
@@ -9,7 +9,7 @@
 def system_info():
     return {
         'name': 'RouteForge',
-        'version': 'v0.4.1-alpha',
+        'version': 'v0.4.2-alpha',
         'demo_mode': settings.demo_mode,
         'read_only': True,
         'data_sources': ['RIPEstat', 'RIPEstat Whois/Registry'],
diff --git a/backend/app/config.py b/backend/app/config.py
index e2d2c87..851dd0c 100644
--- a/backend/app/config.py
+++ b/backend/app/config.py
@@ -8,6 +8,10 @@ class Settings(BaseSettings):
     database_url: str = "sqlite:///./routeforge.db"
     ripestat_base_url: str = "https://stat.ripe.net/data"
     http_timeout_seconds: int = 10
+    ripestat_timeout_seconds: float = 10
+    ripestat_max_retries: int = 1
+    ripestat_retry_backoff_seconds: float = 0.5
+    ripestat_use_stale_cache_on_error: bool = True
     cache_ttl_seconds: int = Field(default=900, validation_alias="RIPESTAT_CACHE_TTL_SECONDS")
     cors_origins: str = "http://192.168.58.167:3000,http://127.0.0.1:3000"
     demo_mode: bool = Field(default=False, validation_alias="ROUTEFORGE_DEMO_MODE")
diff --git a/backend/app/core/source_diagnostics.py b/backend/app/core/source_diagnostics.py
index 3f80af5..2f39ce8 100644
--- a/backend/app/core/source_diagnostics.py
+++ b/backend/app/core/source_diagnostics.py
@@ -72,6 +72,11 @@ def make_source_diagnostic(
     http_status: int | None = None,
     error_type: str | None = None,
     details: dict[str, Any] | None = None,
+    retry_count: int | None = None,
+    attempts: int | None = None,
+    fallback_used: bool | None = None,
+    fallback_reason: str | None = None,
+    stale_cache_used: bool | None = None,
 ) -> dict[str, Any]:
     return {
         "name": name,
@@ -88,4 +93,9 @@ def make_source_diagnostic(
         "http_status": http_status,
         "error_type": error_type,
         "details": details or {},
+        "retry_count": retry_count,
+        "attempts": attempts,
+        "fallback_used": fallback_used,
+        "fallback_reason": fallback_reason,
+        "stale_cache_used": stale_cache_used,
     }
diff --git a/backend/app/main.py b/backend/app/main.py
index b476d06..68a1854 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -8,7 +8,7 @@
 from app.config import settings
 from app.database import Base, engine
 
-app = FastAPI(title="RouteForge", version="0.4.1")
+app = FastAPI(title="RouteForge", version="0.4.2")
 
 app.add_middleware(
     CORSMiddleware,
diff --git a/backend/app/services/ripe_stat_client.py b/backend/app/services/ripe_stat_client.py
index ba4f588..09a8b18 100644
--- a/backend/app/services/ripe_stat_client.py
+++ b/backend/app/services/ripe_stat_client.py
@@ -5,17 +5,7 @@
 from sqlalchemy.orm import Session
 
 import app.config as config
-from app.core.source_diagnostics import (
-    EMPTY_RESPONSE,
-    ERROR,
-    HTTP_ERROR,
-    OK,
-    PARSE_ERROR,
-    RATE_LIMITED,
-    TIMEOUT,
-    make_cache_metadata,
-    make_source_diagnostic,
-)
+from app.core.source_diagnostics import EMPTY_RESPONSE, ERROR, HTTP_ERROR, OK, PARSE_ERROR, RATE_LIMITED, TIMEOUT, make_cache_metadata, make_source_diagnostic
 from app.services.cache import _cache_key, get_cached, set_cached
 
 
@@ -27,159 +17,157 @@ def get(self, endpoint: str, params: dict) -> dict:
         payload, _diagnostic = self.get_with_diagnostics(endpoint, params)
         return payload or {"error": "empty response", "endpoint": endpoint, "params": params}
 
+    def _read_cache_entry(self, endpoint: str, params: dict):
+        cached_payload = get_cached(self.db, endpoint, params)
+        if not cached_payload:
+            return None
+        if isinstance(cached_payload, dict) and "payload" in cached_payload:
+            payload = cached_payload.get("payload")
+            fetched_at = cached_payload.get("fetched_at")
+            ttl = int(cached_payload.get("ttl_seconds") or config.settings.cache_ttl_seconds)
+        else:
+            payload = cached_payload
+            fetched_at = None
+            ttl = int(config.settings.cache_ttl_seconds)
+        age_seconds = None
+        expires_at = None
+        if isinstance(fetched_at, str):
+            try:
+                fetched_dt = datetime.fromisoformat(fetched_at)
+                if fetched_dt.tzinfo is None:
+                    fetched_dt = fetched_dt.replace(tzinfo=UTC)
+                age_seconds = max(0, int((datetime.now(UTC) - fetched_dt).total_seconds()))
+                expires_at = (fetched_dt + timedelta(seconds=ttl)).isoformat()
+            except ValueError:
+                fetched_at = None
+        return {"payload": payload, "fetched_at": fetched_at, "ttl": ttl, "age_seconds": age_seconds, "expires_at": expires_at}
+
     def get_with_diagnostics(self, endpoint: str, params: dict, force_refresh: bool = False) -> tuple[dict | None, dict]:
         started = time.perf_counter()
         cache_key = _cache_key(endpoint, params)
+
         if config.settings.demo_mode:
             payload = self._get_demo_data(endpoint, params)
-            cache_meta = make_cache_metadata(cached=False)
-            return payload, make_source_diagnostic(
-                name=f"RIPEstat {endpoint}",
-                endpoint=endpoint,
-                status=OK,
-                message="Demo data returned",
-                duration_ms=int((time.perf_counter() - started) * 1000),
-                **cache_meta,
-                details={"demo_mode": True, "force_refresh": force_refresh, "cache_key": cache_key},
-            )
+            return payload, make_source_diagnostic(name=f"RIPEstat {endpoint}", endpoint=endpoint, status=OK, message="Demo data returned", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", attempts=1, retry_count=0, fallback_used=False, stale_cache_used=False, details={"demo_mode": True, "force_refresh": force_refresh, "cache_key": cache_key})
 
         if not force_refresh:
-            cached_payload = get_cached(self.db, endpoint, params)
-            if cached_payload:
-                payload = cached_payload if isinstance(cached_payload, dict) else {"payload": cached_payload}
-                # backward compatibility: older cache may store raw payload
-                if "payload" in payload and "fetched_at" in payload:
-                    wrapped = payload
-                else:
-                    wrapped = {"payload": payload, "fetched_at": datetime.now(UTC).isoformat(), "ttl_seconds": config.settings.cache_ttl_seconds, "cache_key": cache_key}
-
-                fetched_dt = datetime.fromisoformat(wrapped["fetched_at"]).replace(tzinfo=UTC)
-                age_seconds = max(0, int((datetime.now(UTC) - fetched_dt).total_seconds()))
-                ttl = int(wrapped.get("ttl_seconds") or config.settings.cache_ttl_seconds)
-                expires_at = (fetched_dt + timedelta(seconds=ttl)).isoformat()
-                cache_meta = make_cache_metadata(True, age_seconds, ttl, wrapped["fetched_at"], expires_at)
-                return wrapped.get("payload"), make_source_diagnostic(
-                    name=f"RIPEstat {endpoint}",
-                    endpoint=endpoint,
-                    status=OK,
-                    message="RIPEstat response served from cache",
-                    duration_ms=int((time.perf_counter() - started) * 1000),
-                    **cache_meta,
-                    details={"cache_key": cache_key, "fetched_at": wrapped["fetched_at"], "expires_at": expires_at, "force_refresh": False},
-                )
+            cache_entry = self._read_cache_entry(endpoint, params)
+            if cache_entry:
+                cache_meta = make_cache_metadata(True, cache_entry["age_seconds"], cache_entry["ttl"], cache_entry["fetched_at"], cache_entry["expires_at"])
+                return cache_entry["payload"], make_source_diagnostic(name=f"RIPEstat {endpoint}", endpoint=endpoint, status=OK, message="RIPEstat response served from cache", duration_ms=int((time.perf_counter() - started) * 1000), attempts=1, retry_count=0, fallback_used=False, stale_cache_used=False, **cache_meta, details={"cache_key": cache_key, "force_refresh": False})
 
         url = f"{config.settings.ripestat_base_url.rstrip('/')}/{endpoint}/data.json"
-        try:
-            with httpx.Client(timeout=config.settings.http_timeout_seconds) as client:
-                resp = client.get(url, params=params)
-                if resp.status_code == 429:
-                    return {"error": "rate limited", "endpoint": endpoint, "params": params}, make_source_diagnostic(
-                        name=f"RIPEstat {endpoint}", endpoint=endpoint, status=RATE_LIMITED, message="RIPEstat rate limit reached", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", http_status=resp.status_code, error_type="http_429", details={"cache_key": cache_key, "force_refresh": force_refresh}
-                    )
-                resp.raise_for_status()
-                data = resp.json()
-        except httpx.TimeoutException as exc:
-            return {"error": str(exc), "endpoint": endpoint, "params": params}, make_source_diagnostic(
-                name=f"RIPEstat {endpoint}", endpoint=endpoint, status=TIMEOUT, message="RIPEstat did not respond before timeout", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", error_type=type(exc).__name__, details={"cache_key": cache_key, "force_refresh": force_refresh}
-            )
-        except httpx.HTTPStatusError as exc:
-            return {"error": str(exc), "endpoint": endpoint, "params": params}, make_source_diagnostic(
-                name=f"RIPEstat {endpoint}", endpoint=endpoint, status=HTTP_ERROR, message="RIPEstat responded with HTTP error", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", http_status=exc.response.status_code, error_type=type(exc).__name__, details={"cache_key": cache_key, "force_refresh": force_refresh}
-            )
-        except ValueError as exc:
-            return {"error": str(exc), "endpoint": endpoint, "params": params}, make_source_diagnostic(
-                name=f"RIPEstat {endpoint}", endpoint=endpoint, status=PARSE_ERROR, message="RIPEstat response could not be parsed as JSON", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", error_type=type(exc).__name__, details={"cache_key": cache_key, "force_refresh": force_refresh}
-            )
-        except Exception as exc:
-            return {"error": str(exc), "endpoint": endpoint, "params": params}, make_source_diagnostic(
-                name=f"RIPEstat {endpoint}", endpoint=endpoint, status=ERROR, message="RIPEstat request failed", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", error_type=type(exc).__name__, details={"cache_key": cache_key, "force_refresh": force_refresh}
-            )
+        max_retries = 0 if config.settings.demo_mode else int(config.settings.ripestat_max_retries)
+        timeout = float(config.settings.ripestat_timeout_seconds or config.settings.http_timeout_seconds)
+        backoff = float(config.settings.ripestat_retry_backoff_seconds)
+        attempts = 0
+        last_status = ERROR
+        last_message = "RIPEstat request failed"
+        last_error_type = None
+        last_http_status = None
+        last_details = {"cache_key": cache_key, "force_refresh": force_refresh}
+
+        with httpx.Client(timeout=timeout) as client:
+            while attempts <= max_retries:
+                attempts += 1
+                try:
+                    resp = client.get(url, params=params)
+                    if resp.status_code == 429:
+                        retry_after = resp.headers.get("Retry-After")
+                        details = {**last_details}
+                        if retry_after:
+                            details["retry_after"] = retry_after
+                        last_details = details
+                        last_status = RATE_LIMITED
+                        last_message = "RIPEstat rate limit reached"
+                        last_http_status = 429
+                        break
+                    if resp.status_code in {400, 401, 403, 404}:
+                        last_status = HTTP_ERROR
+                        last_message = "RIPEstat responded with HTTP error"
+                        last_http_status = resp.status_code
+                        break
+                    if resp.status_code in {502, 503, 504}:
+                        last_status = HTTP_ERROR
+                        last_message = "RIPEstat responded with HTTP error"
+                        last_http_status = resp.status_code
+                        if attempts <= max_retries:
+                            time.sleep(backoff * (2 ** (attempts - 1)))
+                            continue
+                        break
+                    resp.raise_for_status()
+                    data = resp.json()
+                    if not data:
+                        return data, make_source_diagnostic(name=f"RIPEstat {endpoint}", endpoint=endpoint, status=EMPTY_RESPONSE, message="RIPEstat returned an empty response", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", attempts=attempts, retry_count=max(0, attempts - 1), fallback_used=False, stale_cache_used=False, details=last_details)
 
-        if not data:
-            return data, make_source_diagnostic(
-                name=f"RIPEstat {endpoint}", endpoint=endpoint, status=EMPTY_RESPONSE, message="RIPEstat returned an empty response", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", details={"cache_key": cache_key, "force_refresh": force_refresh}
-            )
+                    fetched_at = datetime.now(UTC).isoformat()
+                    ttl = config.settings.cache_ttl_seconds
+                    expires_at = (datetime.now(UTC) + timedelta(seconds=ttl)).isoformat()
+                    set_cached(self.db, endpoint, params, {"payload": data, "fetched_at": fetched_at, "ttl_seconds": ttl, "cache_key": cache_key})
+                    cache_meta = make_cache_metadata(False, None, ttl, fetched_at, expires_at)
+                    return data, make_source_diagnostic(name=f"RIPEstat {endpoint}", endpoint=endpoint, status=OK, message="RIPEstat response received", duration_ms=int((time.perf_counter() - started) * 1000), attempts=attempts, retry_count=max(0, attempts - 1), fallback_used=False, stale_cache_used=False, **cache_meta, details={**last_details, "fetched_at": fetched_at, "expires_at": expires_at})
+                except httpx.TimeoutException as exc:
+                    last_status = TIMEOUT
+                    last_message = f"Request timed out after {attempts} attempts"
+                    last_error_type = type(exc).__name__
+                    if attempts <= max_retries:
+                        time.sleep(backoff * (2 ** (attempts - 1)))
+                        continue
+                    break
+                except httpx.HTTPStatusError as exc:
+                    last_status = HTTP_ERROR
+                    last_message = "RIPEstat responded with HTTP error"
+                    last_http_status = exc.response.status_code
+                    if exc.response.status_code in {502, 503, 504} and attempts <= max_retries:
+                        time.sleep(backoff * (2 ** (attempts - 1)))
+                        continue
+                    break
+                except httpx.RequestError as exc:
+                    last_status = ERROR
+                    last_message = "RIPEstat network request failed"
+                    last_error_type = type(exc).__name__
+                    if attempts <= max_retries:
+                        time.sleep(backoff * (2 ** (attempts - 1)))
+                        continue
+                    break
+                except ValueError as exc:
+                    return {"error": str(exc), "endpoint": endpoint, "params": params}, make_source_diagnostic(name=f"RIPEstat {endpoint}", endpoint=endpoint, status=PARSE_ERROR, message="RIPEstat response could not be parsed as JSON", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", attempts=attempts, retry_count=max(0, attempts - 1), fallback_used=False, stale_cache_used=False, error_type=type(exc).__name__, details=last_details)
+                except Exception as exc:
+                    last_status = ERROR
+                    last_message = "RIPEstat request failed"
+                    last_error_type = type(exc).__name__
+                    break
 
-        fetched_at = datetime.now(UTC).isoformat()
-        ttl = config.settings.cache_ttl_seconds
-        expires_at = (datetime.now(UTC) + timedelta(seconds=ttl)).isoformat()
-        set_cached(self.db, endpoint, params, {"payload": data, "fetched_at": fetched_at, "ttl_seconds": ttl, "cache_key": cache_key})
-        cache_meta = make_cache_metadata(False, None, ttl, fetched_at, expires_at)
-        return data, make_source_diagnostic(
-            name=f"RIPEstat {endpoint}", endpoint=endpoint, status=OK, message="RIPEstat response received", duration_ms=int((time.perf_counter() - started) * 1000), **cache_meta, details={"cache_key": cache_key, "fetched_at": fetched_at, "expires_at": expires_at, "force_refresh": force_refresh}
-        )
+        if config.settings.ripestat_use_stale_cache_on_error:
+            cache_entry = self._read_cache_entry(endpoint, params)
+            if cache_entry:
+                cache_meta = make_cache_metadata(True, cache_entry["age_seconds"], cache_entry["ttl"], cache_entry["fetched_at"], cache_entry["expires_at"])
+                cache_meta["freshness"] = "STALE"
+                reason = "rate_limited" if last_status == RATE_LIMITED else "timeout" if last_status == TIMEOUT else "http_error" if last_status == HTTP_ERROR else "network_error"
+                return cache_entry["payload"], make_source_diagnostic(name=f"RIPEstat {endpoint}", endpoint=endpoint, status=last_status, message="Live request failed; stale cached response used", duration_ms=int((time.perf_counter() - started) * 1000), attempts=attempts, retry_count=max(0, attempts - 1), fallback_used=True, fallback_reason=reason, stale_cache_used=True, http_status=last_http_status, error_type=last_error_type, **cache_meta, details=last_details)
+
+        return None, make_source_diagnostic(name=f"RIPEstat {endpoint}", endpoint=endpoint, status=last_status, message=f"RIPEstat {endpoint} could not be queried after {attempts} attempts.", duration_ms=int((time.perf_counter() - started) * 1000), cached=False, freshness="LIVE", attempts=attempts, retry_count=max(0, attempts - 1), fallback_used=False, stale_cache_used=False, http_status=last_http_status, error_type=last_error_type, details=last_details)
 
     def _get_demo_data(self, endpoint: str, params: dict) -> dict:
         resource = str(params.get("resource", "")).upper()
         if endpoint == "as-overview" and resource == "AS3320":
-            return {
-                "data": {
-                    "resource": "AS3320",
-                    "holder": "DEMO: Deutsche Telekom AG",
-                    "announced": True,
-                },
-                "demo_mode": True,
-            }
+            return {"data": {"resource": "AS3320", "holder": "DEMO: Deutsche Telekom AG", "announced": True}, "demo_mode": True}
         if endpoint == "announced-prefixes" and resource == "AS3320":
-            return {
-                "data": {
-                    "resource": "AS3320",
-                    "organisation": "Demo Networks Ltd.",
-                    "as-name": "DEMO-AS",
-                    "prefixes": [
-                        {"prefix": "192.0.2.0/24"},
-                        {"prefix": "198.51.100.0/24"},
-                        {"prefix": "203.0.113.0/24"},
-                        {"prefix": "2001:db8::/32"},
-                    ],
-                },
-                "demo_mode": True,
-            }
+            return {"data": {"resource": "AS3320", "organisation": "Demo Networks Ltd.", "as-name": "DEMO-AS", "prefixes": [{"prefix": "192.0.2.0/24"}, {"prefix": "198.51.100.0/24"}, {"prefix": "203.0.113.0/24"}, {"prefix": "2001:db8::/32"}]}, "demo_mode": True}
         if endpoint == "as-overview" and resource == "AS4491":
-            return {
-                "data": {
-                    "resource": "AS4491",
-                    "holder": "DEMO: CNC Group CHINA169 Backbone",
-                    "announced": False,
-                },
-                "demo_mode": True,
-            }
+            return {"data": {"resource": "AS4491", "holder": "DEMO: CNC Group CHINA169 Backbone", "announced": False}, "demo_mode": True}
         if endpoint == "announced-prefixes" and resource == "AS4491":
-            return {
-                "data": {
-                    "resource": "AS4491",
-                    "prefixes": [],
-                },
-                "demo_mode": True,
-            }
+            return {"data": {"resource": "AS4491", "prefixes": []}, "demo_mode": True}
         if endpoint == "whois":
-            return {
-                "data": {
-                    "resource": resource,
-                    "records": [{"key": "organisation", "value": "Demo Networks Ltd."}, {"key": "netname", "value": "DEMO-NET"}],
-                    "holder": "Demo Networks Ltd.",
-                },
-                "demo_mode": True,
-            }
+            return {"data": {"resource": resource, "records": [{"key": "organisation", "value": "Demo Networks Ltd."}, {"key": "netname", "value": "DEMO-NET"}], "holder": "Demo Networks Ltd."}, "demo_mode": True}
         if endpoint == "routing-status":
-            demo_routing = {
-                "192.0.2.0/24": {"data": {"routes": [{"origin": "AS3320"}]}, "demo_mode": True},
-                "198.51.100.0/24": {"data": {"routes": [{"origin": "AS64496"}]}, "demo_mode": True},
-                "203.0.113.0/24": {"data": {"visibility": [{"prefix": "203.0.113.0/24"}]}, "demo_mode": True},
-                "203.0.114.0/24": {"error": "demo upstream timeout", "demo_mode": True},
-            }
+            demo_routing = {"192.0.2.0/24": {"data": {"routes": [{"origin": "AS3320"}]}, "demo_mode": True}, "198.51.100.0/24": {"data": {"routes": [{"origin": "AS64496"}]}, "demo_mode": True}, "203.0.113.0/24": {"data": {"visibility": [{"prefix": "203.0.113.0/24"}]}, "demo_mode": True}, "203.0.114.0/24": {"error": "demo upstream timeout", "demo_mode": True}}
             return demo_routing.get(resource.lower(), {"data": {}, "demo_mode": True})
-
         if endpoint == "rpki-validation":
             prefix = str(params.get("resource", "")).lower()
             origin_param = params.get('prefix') or params.get('origin_asn') or params.get('origin')
             origin = str(origin_param or '').strip().upper()
-            statuses = {
-                ("192.0.2.0/24", "AS3320"): "valid",
-                ("198.51.100.0/24", "AS3320"): "invalid_asn",
-                ("203.0.113.0/24", "AS3320"): "invalid_length",
-                ("2001:db8::/32", "AS3320"): "unknown",
-            }
+            statuses = {("192.0.2.0/24", "AS3320"): "valid", ("198.51.100.0/24", "AS3320"): "invalid_asn", ("203.0.113.0/24", "AS3320"): "invalid_length", ("2001:db8::/32", "AS3320"): "unknown"}
             status = statuses.get((prefix, origin), "unknown")
             return {"data": {"status": status}, "demo_mode": True}
         return {"error": f"No demo data for endpoint '{endpoint}'", "endpoint": endpoint, "params": params, "demo_mode": True}
diff --git a/backend/app/templates/report.html.j2 b/backend/app/templates/report.html.j2
index c2f1100..6ff5daa 100644
--- a/backend/app/templates/report.html.j2
+++ b/backend/app/templates/report.html.j2
@@ -50,7 +50,7 @@
 </ul>
 
 <h2>Data Source Diagnostics</h2>
-{% if report.details and report.details.source_diagnostics %}<table border="1" cellpadding="6" cellspacing="0"><tr><th>Quelle</th><th>Endpoint</th><th>Status</th><th>Dauer</th><th>Freshness</th><th>Cache</th><th>Cache Age</th><th>TTL</th><th>Message</th></tr>{% for d in report.details.source_diagnostics %}<tr><td>{{ d.name or '-' }}</td><td>{{ d.endpoint or '-' }}</td><td>{{ d.status or '-' }}</td><td>{{ d.duration_ms if d.duration_ms is not none else '-' }}</td><td>{{ d.freshness or 'UNKNOWN' }}</td><td>{{ 'HIT' if d.cached is sameas true else ('MISS' if d.cached is sameas false else '-') }}</td><td>{{ d.cache_age_seconds if d.cache_age_seconds is not none else 'Unknown' }}</td><td>{{ d.cache_ttl_seconds if d.cache_ttl_seconds is not none else 'Unknown' }}</td><td>{{ d.message or '-' }}{% if d.details %}<details><summary>Details</summary><pre>{{ d.details | tojson(indent=2) }}</pre></details>{% endif %}</td></tr>{% endfor %}</table>{% else %}<p>No source diagnostics available.</p>{% endif %}
+{% if report.details and report.details.source_diagnostics %}<table border="1" cellpadding="6" cellspacing="0"><tr><th>Quelle</th><th>Endpoint</th><th>Status</th><th>Freshness</th><th>Attempts</th><th>Retries</th><th>Fallback</th><th>Stale Cache</th><th>Dauer</th><th>Cache</th><th>Cache Age</th><th>TTL</th><th>Message</th></tr>{% for d in report.details.source_diagnostics %}<tr><td>{{ d.name or '-' }}</td><td>{{ d.endpoint or '-' }}</td><td>{{ d.status or '-' }}</td><td>{{ d.freshness or 'UNKNOWN' }}</td><td>{{ d.attempts if d.attempts is not none else '-' }}</td><td>{{ d.retry_count if d.retry_count is not none else '-' }}</td><td>{{ 'yes' if d.fallback_used is sameas true else ('no' if d.fallback_used is sameas false else '-') }}</td><td>{{ 'yes' if d.stale_cache_used is sameas true else ('no' if d.stale_cache_used is sameas false else '-') }}</td><td>{{ d.duration_ms if d.duration_ms is not none else '-' }}</td><td>{{ 'HIT' if d.cached is sameas true else ('MISS' if d.cached is sameas false else '-') }}</td><td>{{ d.cache_age_seconds if d.cache_age_seconds is not none else 'Unknown' }}</td><td>{{ d.cache_ttl_seconds if d.cache_ttl_seconds is not none else 'Unknown' }}</td><td>{{ d.message or '-' }}{% if d.fallback_used is sameas true %}<div><em>Live request failed. Cached data was used.</em></div>{% endif %}{% if d.details %}<details><summary>Details</summary><pre>{{ d.details | tojson(indent=2) }}</pre></details>{% endif %}</td></tr>{% endfor %}</table>{% else %}<p>No source diagnostics available.</p>{% endif %}
 
 <h2>Rohdaten</h2>
 <h3>RPKI Rohdaten</h3>
diff --git a/backend/app/templates/report.md.j2 b/backend/app/templates/report.md.j2
index a5a214d..34e01e3 100644
--- a/backend/app/templates/report.md.j2
+++ b/backend/app/templates/report.md.j2
@@ -43,9 +43,9 @@
 
 ## Data Source Diagnostics
 {% if report.details and report.details.source_diagnostics %}
-| Quelle | Endpoint | Status | Dauer | Freshness | Cache | Cache Age | TTL | Message |
+| Quelle | Endpoint | Status | Freshness | Attempts | Retries | Fallback | Stale Cache | Dauer | Cache | Cache Age | TTL | Message |
 |---|---|---|---:|---|---|
-{% for d in report.details.source_diagnostics %}| {{ d.name or '-' }} | {{ d.endpoint or '-' }} | {{ d.status or '-' }} | {{ d.duration_ms if d.duration_ms is not none else '-' }} | {{ d.freshness or 'UNKNOWN' }} | {{ 'HIT' if d.cached is sameas true else ('MISS' if d.cached is sameas false else '-') }} | {{ d.cache_age_seconds if d.cache_age_seconds is not none else 'Unknown' }} | {{ d.cache_ttl_seconds if d.cache_ttl_seconds is not none else 'Unknown' }} | {{ d.message or '-' }} |
+{% for d in report.details.source_diagnostics %}| {{ d.name or '-' }} | {{ d.endpoint or '-' }} | {{ d.status or '-' }} | {{ d.freshness or 'UNKNOWN' }} | {{ d.attempts if d.attempts is not none else '-' }} | {{ d.retry_count if d.retry_count is not none else '-' }} | {{ 'yes' if d.fallback_used is sameas true else ('no' if d.fallback_used is sameas false else '-') }} | {{ 'yes' if d.stale_cache_used is sameas true else ('no' if d.stale_cache_used is sameas false else '-') }} | {{ d.duration_ms if d.duration_ms is not none else '-' }} | {{ 'HIT' if d.cached is sameas true else ('MISS' if d.cached is sameas false else '-') }} | {{ d.cache_age_seconds if d.cache_age_seconds is not none else 'Unknown' }} | {{ d.cache_ttl_seconds if d.cache_ttl_seconds is not none else 'Unknown' }} | {{ d.message or '-' }}{% if d.fallback_used is sameas true %} (Live request failed. Cached data was used.){% endif %} |
 {% endfor %}
 {% else %}No source diagnostics available.
 {% endif %}
diff --git a/backend/pyproject.toml b/backend/pyproject.toml
index beaa6e3..f6fc655 100644
--- a/backend/pyproject.toml
+++ b/backend/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "routeforge-backend"
-version = "0.4.1"
+version = "0.4.2"
 description = "RouteForge backend"
 requires-python = ">=3.12"
 dependencies = [
diff --git a/backend/tests/test_api_smoke.py b/backend/tests/test_api_smoke.py
index 754f931..b0a1744 100644
--- a/backend/tests/test_api_smoke.py
+++ b/backend/tests/test_api_smoke.py
@@ -34,7 +34,7 @@ def test_prefix_check_without_origin_as() -> None:
     assert payload.get('markdown')
     assert payload.get('html')
     assert payload.get('details', {}).get('resource_holder')
-    assert any('freshness' in d for d in payload.get('details', {}).get('source_diagnostics', []) if isinstance(d, dict))
+    assert any('attempts' in d for d in payload.get('details', {}).get('source_diagnostics', []) if isinstance(d, dict))
 
 
 def test_asn_check() -> None:
@@ -48,7 +48,7 @@ def test_asn_check() -> None:
     assert 'extracted_prefixes' in details
     assert details.get('rpki_batch', {}).get('available') is True
     assert details.get('resource_holder')
-    assert any('freshness' in d for d in details.get('source_diagnostics', []) if isinstance(d, dict))
+    assert any('attempts' in d for d in details.get('source_diagnostics', []) if isinstance(d, dict))
 
 
 def test_asn_check_without_prefixes_has_batch_reason() -> None:
@@ -114,7 +114,7 @@ def test_preflight_check() -> None:
     assert 'routing_visibility' in checks
     assert payload.get('details', {}).get('preflight_mode') is True
     assert isinstance(payload.get('details', {}).get('source_diagnostics'), list)
-    assert any('freshness' in d for d in payload.get('details', {}).get('source_diagnostics', []) if isinstance(d, dict))
+    assert any('attempts' in d for d in payload.get('details', {}).get('source_diagnostics', []) if isinstance(d, dict))
     assert payload.get('details', {}).get('resource_holder')
     assert payload.get('details', {}).get('preflight_decision') in {'GO', 'CAUTION', 'NO-GO', 'UNKNOWN'}
 
diff --git a/backend/tests/test_ripe_stat_client.py b/backend/tests/test_ripe_stat_client.py
index 95f8b97..f1e415e 100644
--- a/backend/tests/test_ripe_stat_client.py
+++ b/backend/tests/test_ripe_stat_client.py
@@ -1,3 +1,5 @@
+import httpx
+
 from app.config import Settings
 from app.services.ripe_stat_client import RipeStatClient
 
@@ -21,28 +23,73 @@ def commit(self):
         return None
 
 
+def _resp(code=200, payload=None, headers=None):
+    req = httpx.Request('GET', 'https://x')
+    return httpx.Response(code, json=payload or {'data': {'ok': True}}, headers=headers, request=req)
+
+
 def test_demo_mode_diagnostics_live(monkeypatch):
     import app.config as config
-
     monkeypatch.setattr(config, 'settings', Settings(_env_file=None, ROUTEFORGE_DEMO_MODE=True))
+    client = RipeStatClient(DummyDb())
+    _, diag = client.get_with_diagnostics('as-overview', {'resource': 'AS3320'})
+    assert diag['attempts'] == 1 and diag['retry_count'] == 0
+
+
+def test_timeout_then_success(monkeypatch):
+    import app.config as config
     from app.services import ripe_stat_client as module
+    monkeypatch.setattr(config, 'settings', Settings(_env_file=None, ROUTEFORGE_DEMO_MODE=False, ripestat_max_retries=1))
+    calls = {'n': 0}
+    def fake_get(self, *_a, **_k):
+        calls['n'] += 1
+        if calls['n'] == 1:
+            raise httpx.TimeoutException('timeout')
+        return _resp()
+    monkeypatch.setattr(httpx.Client, 'get', fake_get)
+    monkeypatch.setattr(module, 'set_cached', lambda *_a, **_k: None)
+    payload, diag = RipeStatClient(DummyDb()).get_with_diagnostics('routing-status', {'resource': '1.1.1.0/24'}, force_refresh=True)
+    assert payload is not None and diag['status'] == 'OK' and diag['attempts'] == 2 and diag['retry_count'] == 1
 
-    client = RipeStatClient(DummyDb())
-    _payload, diag = client.get_with_diagnostics('as-overview', {'resource': 'AS3320'})
-    assert diag['cached'] is False
-    assert diag['freshness'] == 'LIVE'
-    assert diag['message'] == 'Demo data returned'
 
+def test_503_then_success(monkeypatch):
+    import app.config as config
+    monkeypatch.setattr(config, 'settings', Settings(_env_file=None, ripestat_max_retries=1))
+    seq = iter([_resp(503), _resp(200)])
+    monkeypatch.setattr(httpx.Client, 'get', lambda self,*a,**k: next(seq))
+    payload, diag = RipeStatClient(DummyDb()).get_with_diagnostics('whois', {'resource': '1.1.1.0/24'}, force_refresh=True)
+    assert payload is not None and diag['attempts'] == 2 and diag['status'] == 'OK'
 
-def test_cached_response_has_age(monkeypatch):
+
+def test_404_no_retry(monkeypatch):
     import app.config as config
+    monkeypatch.setattr(config, 'settings', Settings(_env_file=None, ripestat_max_retries=3))
+    monkeypatch.setattr(httpx.Client, 'get', lambda self,*a,**k: _resp(404))
+    payload, diag = RipeStatClient(DummyDb()).get_with_diagnostics('whois', {'resource': 'x'}, force_refresh=True)
+    assert payload is None and diag['attempts'] == 1 and diag['status'] == 'HTTP_ERROR'
+
+
+def test_429_rate_limited(monkeypatch):
+    import app.config as config
+    monkeypatch.setattr(config, 'settings', Settings(_env_file=None, ripestat_max_retries=3))
+    monkeypatch.setattr(httpx.Client, 'get', lambda self,*a,**k: _resp(429, headers={'Retry-After': '60'}))
+    _payload, diag = RipeStatClient(DummyDb()).get_with_diagnostics('whois', {'resource': 'x'}, force_refresh=True)
+    assert diag['status'] == 'RATE_LIMITED' and diag['details'].get('retry_after') == '60'
+
 
-    monkeypatch.setattr(config, 'settings', Settings(_env_file=None, ROUTEFORGE_DEMO_MODE=False))
+def test_timeout_with_stale_cache(monkeypatch):
+    import app.config as config
     from app.services import ripe_stat_client as module
+    monkeypatch.setattr(config, 'settings', Settings(_env_file=None, ripestat_max_retries=0, ripestat_use_stale_cache_on_error=True))
+    monkeypatch.setattr(httpx.Client, 'get', lambda self,*a,**k: (_ for _ in ()).throw(httpx.TimeoutException('t')))
+    monkeypatch.setattr(module, 'get_cached', lambda *_a, **_k: {'payload': {'data': {'cached': True}}})
+    payload, diag = RipeStatClient(DummyDb()).get_with_diagnostics('whois', {'resource': 'x'}, force_refresh=True)
+    assert payload == {'data': {'cached': True}} and diag['fallback_used'] is True and diag['stale_cache_used'] is True and diag['freshness'] == 'STALE'
 
-    monkeypatch.setattr(module, 'get_cached', lambda *_args, **_kwargs: {'payload': {'data': {}}, 'fetched_at': '2026-05-20T00:00:00+00:00', 'ttl_seconds': 900})
-    client = RipeStatClient(DummyDb())
-    _payload, diag = client.get_with_diagnostics('as-overview', {'resource': 'AS3320'})
-    assert diag['cached'] is True
-    assert isinstance(diag['cache_age_seconds'], int)
-    assert diag['cache_ttl_seconds'] == 900
+
+def test_timeout_no_cache(monkeypatch):
+    import app.config as config
+    monkeypatch.setattr(config, 'settings', Settings(_env_file=None, ripestat_max_retries=0, ripestat_use_stale_cache_on_error=True))
+    monkeypatch.setattr(httpx.Client, 'get', lambda self,*a,**k: (_ for _ in ()).throw(httpx.TimeoutException('t')))
+    payload, diag = RipeStatClient(DummyDb()).get_with_diagnostics('whois', {'resource': 'x'}, force_refresh=True)
+    assert payload is None and diag['status'] == 'TIMEOUT'
diff --git a/backend/tests/test_source_diagnostics.py b/backend/tests/test_source_diagnostics.py
index c68ab4f..ddcb9f7 100644
--- a/backend/tests/test_source_diagnostics.py
+++ b/backend/tests/test_source_diagnostics.py
@@ -31,3 +31,11 @@ def test_make_cache_metadata_freshness_rules() -> None:
 def test_known_status_values_present() -> None:
     for value in [OK, TIMEOUT, "HTTP_ERROR", "PARSE_ERROR", "UNKNOWN_STRUCTURE", "RATE_LIMITED", "CACHE_HIT", "CACHE_MISS", "EMPTY_RESPONSE", "NO_DATA", "ERROR"]:
         assert value in KNOWN_SOURCE_STATUSES
+
+
+def test_make_source_diagnostic_retry_fields() -> None:
+    d = make_source_diagnostic("n", "e", OK, "m", attempts=2, retry_count=1, fallback_used=True, stale_cache_used=True)
+    assert d["attempts"] == 2
+    assert d["retry_count"] == 1
+    assert d["fallback_used"] is True
+    assert d["stale_cache_used"] is True
diff --git a/frontend/package-lock.json b/frontend/package-lock.json
index b7156dd..92ba52d 100644
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "routeforge-frontend",
-  "version": "0.4.1",
+  "version": "0.4.2",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "routeforge-frontend",
-      "version": "0.4.1",
+      "version": "0.4.2",
       "dependencies": {
         "react": "^18.3.1",
         "react-dom": "^18.3.1"
diff --git a/frontend/package.json b/frontend/package.json
index 963b3a3..3ce1cca 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -1,6 +1,6 @@
 {
   "name": "routeforge-frontend",
-  "version": "0.4.1",
+  "version": "0.4.2",
   "private": true,
   "type": "module",
   "scripts": {
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index c39f08b..9d2ecb4 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -15,7 +15,7 @@ export default function App() {
   const [copyMessage, setCopyMessage] = useState('')
   const [system, setSystem] = useState<SystemInfo | null>(null)
   useEffect(() => { getReports().then(setReports).catch(() => setReports([])); getSystemInfo().then(setSystem).catch(() => null) }, [])
-  const systemLine = useMemo(() => system ? `${system.name} ${system.version} · mode=${system.demo_mode ? 'DEMO' : 'LIVE'} · read_only=${String(system.read_only)}` : 'RouteForge v0.4.1-alpha · read-only preflight checks', [system])
+  const systemLine = useMemo(() => system ? `${system.name} ${system.version} · mode=${system.demo_mode ? 'DEMO' : 'LIVE'} · read_only=${String(system.read_only)}` : 'RouteForge v0.4.2-alpha · read-only preflight checks', [system])
   const title = { dashboard: 'Dashboard', asn: 'ASN Check', prefix: 'Prefix Check', preflight: 'Preflight Check', reports: 'Reports', about: 'About RouteForge' }[active]
   const notify = (message: string) => {
     setCopyMessage(message)
@@ -37,7 +37,7 @@ export default function App() {
 
   return <Layout active={active} onNav={setActive} systemLine={systemLine} title={title} demoMode={Boolean(system?.demo_mode)}>
     {active === 'dashboard' && <section className='space-y-4'>
-      <article className='rf-card p-6'><h1 className='text-2xl font-bold'>RouteForge v0.4.1-alpha</h1><p className='mt-2 text-slate-600'>Modernes read-only Operator-Tool für Preflight Checks von ASN, Prefix, RPKI und Registry/IRR.</p><p className='mt-3 rf-alert border-slate-200 bg-slate-50 text-slate-700'>Security-Modell: ausschließlich read-only, keine writes/deployments.</p></article>
+      <article className='rf-card p-6'><h1 className='text-2xl font-bold'>RouteForge v0.4.2-alpha</h1><p className='mt-2 text-slate-600'>Modernes read-only Operator-Tool für Preflight Checks von ASN, Prefix, RPKI und Registry/IRR.</p><p className='mt-3 rf-alert border-slate-200 bg-slate-50 text-slate-700'>Security-Modell: ausschließlich read-only, keine writes/deployments.</p></article>
       <div className='grid gap-3 md:grid-cols-3'>{[['ASN Check', 'asn'], ['Prefix Check', 'prefix'], ['Preflight Check', 'preflight'], ['Reports', 'reports']].map(([x, key]) => <button key={x} onClick={() => setActive(key as NavKey)} className='rf-card p-4 text-left hover:border-blue-300'><h3 className='font-semibold'>{x}</h3></button>)}</div>
       <article className='rf-card p-4'><h2 className='mb-2 font-semibold'>Letzte Reports</h2>{reports.length === 0 ? <div className='rounded-xl border border-dashed border-slate-300 p-6 text-sm text-slate-500'>Noch keine Reports vorhanden.</div> : <div className='overflow-x-auto'><table className='w-full text-sm'><thead><tr className='border-b text-left'><th className='py-2'>Zeit</th><th>Typ</th><th>Resource</th><th>Holder</th><th>Status</th></tr></thead><tbody>{reports.slice(0, 8).map(r => <tr key={r.report_id} className='border-b border-slate-100'><td className='py-2'>{new Date(r.created_at).toLocaleString()}</td><td>{r.check_type === 'preflight' ? 'Preflight' : r.check_type}</td><td>{r.input_resource}</td><td>{r.holder || 'Unknown'}</td><td><StatusBadge status={r.status} /></td></tr>)}</tbody></table></div>}</article>
     </section>}
@@ -45,6 +45,6 @@ export default function App() {
     {active === 'prefix' && <PrefixCheckForm />}
     {active === 'preflight' && <PreflightCheckForm />}
     {active === 'reports' && <section className='rf-card p-4'><h2 className='mb-3 text-xl font-semibold'>Reports</h2>{reports.length===0 ? <div className='rounded-xl border border-dashed border-slate-300 p-6 text-sm text-slate-500'>Noch keine Reports vorhanden.</div> : <div className='overflow-x-auto'><table className='w-full text-sm'><thead><tr className='border-b text-left'><th>Zeitpunkt</th><th>Typ</th><th>Resource</th><th>Origin-AS</th><th>Holder</th><th>Status</th><th>Kurzfassung</th><th>Actions</th></tr></thead><tbody>{reports.map(r=><tr key={r.report_id} className='border-b border-slate-100'><td className='py-2'>{new Date(r.created_at).toLocaleString()}</td><td>{r.check_type === 'preflight' ? 'Preflight' : r.check_type}</td><td>{r.input_resource}</td><td>{r.origin_as || '-'}</td><td>{r.holder || 'Unknown'}</td><td><StatusBadge status={r.status} /></td><td>{r.summary}</td><td><div className='flex flex-wrap gap-1'><button className='rf-btn-secondary' onClick={() => window.open(`/api/reports/${r.report_id}`, '_blank')}>Open</button><button className='rf-btn-secondary' onClick={async ()=>copyText(await getReportSummary(r.report_id), 'Summary copied')}>Copy Summary</button><button className='rf-btn-secondary' onClick={async ()=>downloadText(`routeforge-report-${r.report_id}.md`, await getReportMarkdown(r.report_id), 'text/markdown;charset=utf-8')}>Download Markdown</button><button className='rf-btn-secondary' onClick={async ()=>downloadText(`routeforge-report-${r.report_id}.html`, await getReportHtml(r.report_id), 'text/html;charset=utf-8')}>Download HTML</button></div></td></tr>)}</tbody></table></div>}{copyMessage && <p className='mt-2 text-sm text-slate-600'>{copyMessage}</p>}</section>}
-    {active === 'about' && <section className='rf-card p-5 space-y-2 text-sm text-slate-700'><p>RouteForge liefert nachvollziehbare Routing-Preflightchecks für technische Operator-Workflows.</p><p><b>Datenquellen:</b> RPKI Validator APIs und Registry/IRR Quellen.</p><p><b>Modell:</b> read-only Betrieb.</p><p><b>Limitations:</b> Externe Datenquellen können unvollständig oder verzögert sein.</p><p><b>Version:</b> v0.4.1-alpha</p></section>}
+    {active === 'about' && <section className='rf-card p-5 space-y-2 text-sm text-slate-700'><p>RouteForge liefert nachvollziehbare Routing-Preflightchecks für technische Operator-Workflows.</p><p><b>Datenquellen:</b> RPKI Validator APIs und Registry/IRR Quellen.</p><p><b>Modell:</b> read-only Betrieb.</p><p><b>Limitations:</b> Externe Datenquellen können unvollständig oder verzögert sein.</p><p><b>Version:</b> v0.4.2-alpha</p></section>}
   </Layout>
 }
diff --git a/frontend/src/components/Layout.tsx b/frontend/src/components/Layout.tsx
index 188ea05..a4d2d18 100644
--- a/frontend/src/components/Layout.tsx
+++ b/frontend/src/components/Layout.tsx
@@ -27,7 +27,7 @@ export function Layout({ children, active, onNav, systemLine, title, demoMode }:
           <div className='flex flex-wrap gap-2 text-xs font-semibold'>
             <span className={`rounded-full border px-3 py-1 ${demoMode ? 'border-amber-300 bg-amber-50 text-amber-700' : 'border-emerald-300 bg-emerald-50 text-emerald-700'}`}>{demoMode ? 'DEMO' : 'LIVE'}</span>
             <span className='rounded-full border border-blue-200 bg-blue-50 px-3 py-1 text-blue-700'>READ-ONLY</span>
-            <span className='rounded-full border border-slate-200 bg-slate-50 px-3 py-1 text-slate-700'>v0.4.1-alpha</span>
+            <span className='rounded-full border border-slate-200 bg-slate-50 px-3 py-1 text-slate-700'>v0.4.2-alpha</span>
           </div>
         </header>
         <main className='space-y-4'>{children}</main>
diff --git a/frontend/src/components/ReportView.tsx b/frontend/src/components/ReportView.tsx
index 8ed32cf..abe01e3 100644
--- a/frontend/src/components/ReportView.tsx
+++ b/frontend/src/components/ReportView.tsx
@@ -89,7 +89,7 @@ export function ReportView({ report }: { report: CheckResponse }) {
     </section>
 
 
-    {sourceDiagnostics.length > 0 && <section className='rf-card p-4 space-y-2'><h4 className='font-semibold'>Data Source Diagnostics</h4><div className='overflow-x-auto'><table className='w-full text-sm'><thead><tr className='border-b text-left'><th className='py-2'>Source</th><th>Endpoint</th><th>Status</th><th>Freshness</th><th>Duration</th><th>Cache</th><th>Age</th><th>TTL</th><th>Message</th></tr></thead><tbody>{sourceDiagnostics.map((d, idx) => <tr key={`${d.name}-${idx}`} className='border-b border-slate-100'><td>{d.name || '-'}</td><td className='font-mono'>{d.endpoint || '-'}</td><td><StatusBadge status={d.status || 'UNKNOWN'} /></td><td className={freshnessClass(d.freshness)}>{d.freshness || 'UNKNOWN'}</td><td>{typeof d.duration_ms === 'number' ? `${d.duration_ms} ms` : '-'}</td><td>{d.cached === true ? 'HIT' : d.cached === false ? 'MISS' : '-'}</td><td>{typeof d.cache_age_seconds === 'number' ? formatDurationSeconds(d.cache_age_seconds) : 'Unknown'}</td><td>{typeof d.cache_ttl_seconds === 'number' ? formatDurationSeconds(d.cache_ttl_seconds) : 'Unknown'}</td><td>{d.message || '-'}</td></tr>)}</tbody></table></div></section>}
+    {sourceDiagnostics.length > 0 && <section className='rf-card p-4 space-y-2'><h4 className='font-semibold'>Data Source Diagnostics</h4><div className='overflow-x-auto'><table className='w-full text-sm'><thead><tr className='border-b text-left'><th className='py-2'>Source</th><th>Endpoint</th><th>Status</th><th>Freshness</th><th>Attempts</th><th>Retries</th><th>Fallback</th><th>Stale Cache</th><th>Duration</th><th>Cache</th><th>Age</th><th>TTL</th><th>Message</th></tr></thead><tbody>{sourceDiagnostics.map((d, idx) => <tr key={`${d.name}-${idx}`} className='border-b border-slate-100'><td>{d.name || '-'}</td><td className='font-mono'>{d.endpoint || '-'}</td><td><StatusBadge status={d.status || 'UNKNOWN'} /></td><td className={freshnessClass(d.freshness)}>{d.freshness || 'UNKNOWN'}</td><td>{typeof d.attempts === 'number' ? d.attempts : '-'}</td><td>{typeof d.retry_count === 'number' ? d.retry_count : '-'}</td><td>{d.fallback_used === true ? 'yes' : d.fallback_used === false ? 'no' : '-'}</td><td>{d.stale_cache_used === true ? 'yes' : d.stale_cache_used === false ? 'no' : '-'}</td><td>{typeof d.duration_ms === 'number' ? `${d.duration_ms} ms` : '-'}</td><td>{d.cached === true ? 'HIT' : d.cached === false ? 'MISS' : '-'}</td><td>{typeof d.cache_age_seconds === 'number' ? formatDurationSeconds(d.cache_age_seconds) : 'Unknown'}</td><td>{typeof d.cache_ttl_seconds === 'number' ? formatDurationSeconds(d.cache_ttl_seconds) : 'Unknown'}</td><td><div>{d.message || '-'}</div>{d.fallback_used === true && <div className='mt-1 rounded border border-amber-200 bg-amber-50 p-2 text-amber-800'>Live request failed. RouteForge used cached data. The result may be outdated.</div>}{d.status === 'RATE_LIMITED' && <div className='mt-1 text-amber-700'>Rate limited by data source.</div>}</td></tr>)}</tbody></table></div></section>}
 
     <details className='rf-card p-4'><summary className='cursor-pointer text-sm font-semibold'>Technische Details</summary><pre className='mt-3 overflow-auto rounded-xl bg-slate-50 p-3 text-xs'>{JSON.stringify({ input: report.input, holder: details.resource_holder, warnings: details.warnings, source_errors: details.source_errors }, null, 2)}</pre></details>
     {sortedResults.length > 0 && <section className='rf-card p-4'><h4 className='mb-2 font-semibold'>Batch Results</h4><div className='overflow-x-auto'><table className='w-full text-sm'><thead><tr className='border-b text-left'><th className='py-2'>Status</th><th>Prefix</th><th>Summary</th></tr></thead><tbody>{sortedResults.map((item, idx) => <tr key={`${item.prefix}-${idx}`} className='border-b border-slate-100'><td className='py-2'><StatusBadge status={item.status || 'UNKNOWN'} /></td><td className='font-mono'>{item.prefix}</td><td>{item.summary || '-'}</td></tr>)}</tbody></table></div></section>}
diff --git a/frontend/src/types.ts b/frontend/src/types.ts
index 8656311..1e14361 100644
--- a/frontend/src/types.ts
+++ b/frontend/src/types.ts
@@ -34,6 +34,11 @@ export type SourceDiagnostic = {
   http_status?: number | null
   error_type?: string | null
   details?: Record<string, unknown>
+  retry_count?: number | null
+  attempts?: number | null
+  fallback_used?: boolean | null
+  fallback_reason?: string | null
+  stale_cache_used?: boolean | null
 }
 
 export type CheckResponse = {