# Delx Idempotency Fingerprint

> Delx Idempotency Fingerprint is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-13).

Generates a deterministic SHA-256 idempotency fingerprint from a caller-supplied scope and JSON payload without storing any state.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/idempotency-fingerprint
- Price: $0.003/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-fingerprint-02317031
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_z9Hg0a6n4NK_Q_1QNT4LQ

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-fingerprint-02317031 -d '<json body>'
```

Example prompt: Before I write this loyalty-event to the ledger, generate an idempotency fingerprint using scope 'loyalty:user-42' and this canonical payload: {"userId":"42","points":150,"eventType":"purchase"} — I need a stable SHA-256 hash to make sure the event doesn't double-apply.

## When to prefer this

Choose this endpoint when you need a stateless, deterministic idempotency key derived from a canonical payload — especially before committing ledger entries, workflow events, or side-effecting operations in multi-step agent pipelines. It is ideal when you want no server-side state storage, no upstream dependency, and a guaranteed reproducible SHA-256 hash from the same inputs. Prefer it over rolling your own hashing logic when you need a paid, auditable, first-party fingerprinting step in an x402-based agent workflow.

## Known failure modes

- Missing or empty scope field returns a validation error
- Payload is not a valid JSON object — returns a schema error
- Malformed request body returns a 400 bad request
- Payment failure or insufficient USDC balance returns a 402 error
- Network timeout on the x402 payment handshake

## How this service works

Create a stable SHA-256 idempotency fingerprint from a scope and canonical payload without storing state — call when writing a ledger or workflow event that must not double-apply. Use before side effects when composing multi-step agent jobs—the same loyalty/workflow demand band agents already pay for on Bazaar, but fully local. Returns deterministic machine-readable JSON for $0.003 USDC via x402 on Base. Execution is first-party, local-only, stateless, and memory-only with no paid upstream, no…

## Output

Returns a deterministic machine-readable JSON object containing the computed SHA-256 fingerprint string derived from the provided scope and canonical payload. No state is stored; the same inputs always produce the same fingerprint, making it safe to call multiple times for verification.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "scope": {
   "type": "string",
   "description": "Caller-owned namespace string mixed into the fingerprint."
  },
  "payload": {
   "type": "object",
   "description": "JSON payload to fingerprint; values are hashed, not retained."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "scope": "loyalty",
  "schema": "delx/util-idempotency-fingerprint/v1",
  "algorithm": "sha256",
  "fingerprint": "dc22b29600e074df71fc0f9b0260185e822b228cca615d37992a31dc14eb8f45",
  "values_returned": false
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-idempotency-fingerprint-02317031/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)