OTDX — Open Tag Detection eXchange

A proposed open standard for sharing tag detection events between networks and providers. One provider tells another, in a verifiable and provider-neutral way:

"These tags were detected at this location during this time window."

{
  "type": "presence",
  "event_id": "0190b7a3-52e4-7cc0-9f4e-3d2a1b9c0d11",
  "provider": "example",
  "tag": "tag:example:mac48:2cdc78051a2b",
  "location": {
    "id": "loc:iata:station:NSN",
    "geo": {"lat": -41.2983, "lon": 173.2210, "radius_m": 70}
  },
  "window": {
    "first_seen": "2026-07-18T02:14:07Z",
    "last_seen": "2026-07-18T02:56:41Z",
    "open": false
  },
  "observations": 46,
  "asserted_at": "2026-07-18T03:00:02Z"
}

Events travel in signed batches (Ed25519), are immutable and uniquely identified (dedup by event_id), and tolerate at-least-once delivery over unreliable links. A tiny mandatory core carries the presence assertion; optional named profiles add signal quality, granular per-detection records, fine positioning, and (opt-in, claim-bound) raw payload relay. See SPEC.md for the full standard.

Repository layout

Path	Contents
SPEC.md	The standard (draft 0.1)
schemas/	JSON Schemas (draft 2020-12) for envelope and record types
examples/valid/	Golden batches — all must PASS validation
examples/invalid/	One rule violation each — all must FAIL validation
examples/keys/	Deterministic TEST-ONLY Ed25519 keypair
tools/otdx-validate	Batch validator (schema, hash, signature, windowing, profiles)
tools/otdx-sign	Keygen / sign / verify for envelopes
reference/	Minimal conforming producer and consumer (~100 lines each)
scripts/generate_examples.py	Regenerates examples/ deterministically
registry/	Issuer short-name registry

Quickstart

Requires Python 3.10+:

pip install -r requirements.txt

Validate a golden example (signature checked with the test key):

python3 tools/otdx-validate --pubkey examples/keys/otdx-test-key.pub \
    examples/valid/01_core_minimal/01_core_minimal.envelope.json

Produce and consume a batch end-to-end:

cd reference
python3 producer.py --provider example --key ../examples/keys/otdx-test-key.pem \
    --key-id otdx-test-1 --in sample_input.csv --out ./out
python3 consumer.py --pubkey ../examples/keys/otdx-test-key.pub \
    --db otdx.sqlite out/*.envelope.json

Run the consumer twice: the second run reports every event as a duplicate — redelivery safety is a conformance requirement, not an optimisation.

Conformance

• Consumer-Core — accepts valid core batches, verifies hash and signature, deduplicates by event_id and batch_id, ignores unknown fields and unknown non-critical profiles, rejects unknown critical profiles.
• Producer-Core — emits schema-valid, signed core batches with correct payload_sha256 and event_count, and never emits overlapping windows for the same (tag, location).
• Per-profile conformance adds the corresponding record types/fields.

The examples/ tree is the test suite: a conforming validator passes everything under valid/ and fails everything under invalid/ for the stated reason.

Status

Draft 0.1 — open for comment. Anything may change before 1.0. See CHANGELOG.md. Field meanings are never reused; deprecate-and-add only.

Licence

Specification text (SPEC.md): CC BY 4.0. Code, schemas, and examples: MIT (see LICENSE).