Online · Live demo server

Idempotent by proof,
not by promise.

A payment engine that guarantees exactly-once processing under concurrent load — with an AI layer that reads its own audit trail and explains, in plain language, why every duplicate was caught.

SHA-256request fingerprinting

Row-level lockSELECT…FOR UPDATE

21/21regression tests passing

AsyncAI layer, zero payment-path risk

Run the proof yourself

Idempotency-Key demo-0380e9a5-fb32-4359-b182-848bebd4f067

Endpoint POST /api/payments/process-payment/

Request 1 · 201

"id": "31c4116a-13f8-4b21-8891-13f82c2a0d1e"
"amount": "125.50"
"status": "completed"
"created_at": "16:28:30.383Z"

Request 2 · 200 (replay)

"id": "31c4116a-13f8-4b21-8891-13f82c2a0d1e"
"amount": "125.50"
"status": "completed"
"created_at": "16:28:30.383Z"

— Same payment ID, same timestamp, one charge. Request 2 never reached the gateway — it was intercepted by the row lock and served from the idempotency cache. No retry logic on your end needed.

Endpoints

Everything below is live. Swap the API key for your own. Click any row to view full cURL or copy directly.

POST

/api/payments/process-payment/

Atomic charge — SHA-256 fingerprint check, row-level lock, self-healing stale-lock recovery.

curl -X POST https://payment-api-3fi4.onrender.com/api/payments/process-payment/ \
  -H "Content-Type: application/json" \
  -H "X-API-KEY: pay_demo.live_reviewer_test_key_2026" \
  -H "Idempotency-Key: demo-key-01" \
  -d '{"amount": "125.50", "currency": "USD", "payer_email": "live@example.com"}'

Core

GET

/api/ai/events/

PII-scrubbed ledger of every attempt, with AI explanations distinguishing benign retries from anomalies.

curl -X GET https://payment-api-3fi4.onrender.com/api/ai/events/ \
  -H "X-API-KEY: pay_demo.live_reviewer_test_key_2026"

AI layer

GET

/api/ai/risk-scores/

Weighted rule-based score, LLM adjustment clamped to ±0.1 with a written justification.

curl -X GET https://payment-api-3fi4.onrender.com/api/ai/risk-scores/ \
  -H "X-API-KEY: pay_demo.live_reviewer_test_key_2026"

AI layer

POST

/api/ai/query/

Ask a question in English. SELECT-only, whitelisted tables, 500-row cap — every query logged.

curl -X POST https://payment-api-3fi4.onrender.com/api/ai/query/ \
  -H "Content-Type: application/json" \
  -H "X-API-KEY: pay_demo.live_reviewer_test_key_2026" \
  -d '{"question": "Show me duplicate payments from the last hour", "auto_execute": true}'

AI layer