diff --git a/packages/registry/src/version-check.test.ts b/packages/registry/src/version-check.test.ts
index 5ba49e0..0312bd7 100644
--- a/packages/registry/src/version-check.test.ts
+++ b/packages/registry/src/version-check.test.ts
@@ -137,6 +137,33 @@ describe("discoverVersions", () => {
     );
   });
 
+  it("fetches hex versions and filters to defined ranges", async () => {
+    const hexDef: VersionedDefinition = {
+      ...mockDefinition,
+      name: "phoenix",
+      registry: "hex",
+    };
+
+    const mockFetch = vi.mocked(fetch);
+    mockFetch.mockResolvedValueOnce({
+      ok: true,
+      json: async () => ({
+        releases: [
+          { version: "1.7.0", inserted_at: "2024-06-01T00:00:00Z" },
+          { version: "1.6.0", inserted_at: "2024-03-01T00:00:00Z" },
+          { version: "1.5.0", inserted_at: "2024-01-01T00:00:00Z" },
+        ],
+      }),
+    } as Response);
+
+    const versions = await discoverVersions(hexDef);
+
+    expect(versions.map((v) => v.version)).toEqual(["1.7.0", "1.6.0", "1.5.0"]);
+    expect(mockFetch).toHaveBeenCalledWith(
+      expect.stringContaining("hex.pm/api/packages/phoenix"),
+    );
+  });
+
   it("throws for unsupported registry", async () => {
     const def = { ...mockDefinition, registry: "cargo" };
     await expect(discoverVersions(def)).rejects.toThrow(
diff --git a/packages/registry/src/version-check.ts b/packages/registry/src/version-check.ts
index ce3bf34..ace0b17 100644
--- a/packages/registry/src/version-check.ts
+++ b/packages/registry/src/version-check.ts
@@ -1,5 +1,5 @@
 /**
- * Version discovery from package registry APIs (npm, pip, maven).
+ * Version discovery from package registry APIs (npm, pip, maven, hex).
  *
  * Queries public registry APIs to find available versions,
  * filters to defined ranges, and deduplicates to latest-patch-per-minor.
@@ -32,6 +32,7 @@ const registryFetchers: Record<string, RegistryFetcher> = {
   npm: fetchNpmVersions,
   pip: fetchPipVersions,
   maven: fetchMavenVersions,
+  hex: fetchHexVersions,
 };
 
 /**
@@ -196,6 +197,29 @@ async function fetchMavenVersions(packageName: string): Promise<VersionInfo[]> {
   }));
 }
 
+/**
+ * Fetch versions from Hex.pm API.
+ * Package names are lowercase with underscores (e.g., "phoenix", "phoenix_live_view").
+ */
+async function fetchHexVersions(packageName: string): Promise<VersionInfo[]> {
+  const res = await fetchWithRetry(
+    `https://hex.pm/api/packages/${encodeURIComponent(packageName)}`,
+    `Hex`,
+    packageName,
+  );
+
+  const data = (await res.json()) as {
+    releases?: Array<{ version?: string; inserted_at?: string }>;
+  };
+
+  const releases = data.releases ?? [];
+
+  return releases.map((r) => ({
+    version: r.version ?? "",
+    publishedAt: r.inserted_at,
+  }));
+}
+
 /**
  * Public registries occasionally return 504/503 under load. Retry 5xx and
  * network errors with exponential backoff; 4xx aborts immediately.
diff --git a/registry/hex/elixir.yaml b/registry/hex/elixir.yaml
new file mode 100644
index 0000000..3f729f7
--- /dev/null
+++ b/registry/hex/elixir.yaml
@@ -0,0 +1,8 @@
+name: elixir
+description: "A dynamic, functional language for building scalable and maintainable applications"
+repository: https://github.com/elixir-lang/elixir
+
+source:
+  type: git
+  url: https://github.com/elixir-lang/elixir
+  docs_path: lib/elixir/pages
diff --git a/registry/hex/phoenix.yaml b/registry/hex/phoenix.yaml
new file mode 100644
index 0000000..fe4a64c
--- /dev/null
+++ b/registry/hex/phoenix.yaml
@@ -0,0 +1,11 @@
+name: phoenix
+description: "A productive web framework for building modern web applications in Elixir"
+repository: https://github.com/phoenixframework/phoenix
+
+versions:
+  - min_version: "1.5.0"
+    source:
+      type: git
+      url: https://github.com/phoenixframework/phoenix
+      docs_path: guides
+    tag_pattern: "v{version}"
diff --git a/registry/hex/phoenix_live_view.yaml b/registry/hex/phoenix_live_view.yaml
new file mode 100644
index 0000000..311676c
--- /dev/null
+++ b/registry/hex/phoenix_live_view.yaml
@@ -0,0 +1,11 @@
+name: phoenix_live_view
+description: "Rich, real-time user experiences with server-rendered HTML in Elixir"
+repository: https://github.com/phoenixframework/phoenix_live_view
+
+versions:
+  - min_version: "0.17.0"
+    source:
+      type: git
+      url: https://github.com/phoenixframework/phoenix_live_view
+      docs_path: guides
+    tag_pattern: "v{version}"