# Delx Idempotency Key

> Delx Idempotency Key is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).

Derives a deterministic, namespaced idempotency key from canonical JSON to prevent duplicate operations in autonomous workflows.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/idempotency-key
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-idempotency-key-1757666d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_hG0k02oWSTlQFmWBF4BjW

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability delx-idempotency-key-1757666d -d '<json body>'
```

Example prompt: Before retrying my payment API call, derive a deterministic idempotency key from this JSON payload in the 'payments' namespace: {"userId":"u_123","amount":50,"currency":"USD"}.

## When to prefer this

Choose this endpoint when you need a fully deterministic, reproducible idempotency key derived from a JSON payload without any external state or upstream provider calls. It is ideal for autonomous agents that must deduplicate actions before retrying requests, acting on untrusted input, or calling state-changing APIs. Prefer it over rolling your own hashing logic when you need a namespaced, canonical, and billing-safe key derivation with structured error responses.

## Known failure modes

- Invalid or non-serializable payload — returns structured validation error without billing
- Namespace exceeds 200 character limit — returns validation error
- Malformed JSON input — structured error returned, no charge incurred
- Payment failure via x402 — request not processed

## How this service works

Derive a deterministic namespaced idempotency key from canonical JSON. Use it before an autonomous workflow acts on untrusted input, changes an API, retries a request, or evaluates production reliability. Returns bounded machine-readable JSON for $0.002 USDC via x402 on Base. Execution is deterministic, first-party, local-only, stateless, and does not call an upstream provider; structured validation failures are not billed.

## Output

Returns a bounded machine-readable JSON object containing the deterministic, namespaced idempotency key derived from the canonical representation of the input JSON payload. Structured validation failures are returned as non-billed error responses.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "payload": {
   "description": "JSON value whose canonical representation identifies one logical operation."
  },
  "namespace": {
   "type": "string",
   "default": "default",
   "maxLength": 200
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "key": "delx_ca094a4752e182cfcac50a38d65de7c7e4f271ee05c08f26853c75f0ba24b049",
  "schema": "delx/idempotency-key/v1",
  "algorithm": "sha256",
  "namespace": "default",
  "payload_sha256": "f85c6736261be7d990522f91e81634f844ad23c515f3b4029e197ab01a2d18dc"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-idempotency-key-1757666d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)