Idempotency Key Builder

Overview

You send the request data that defines "the same request", and we return one short key for it. Two requests that mean the same thing get the same key even if their JSON arrived with different key order, spacing, or number spelling, because we canonicalize with RFC 8785 before hashing with SHA-256. Pick the parts that matter with JSON Pointers and the rest is ignored, so a changing timestamp or trace id does not make a retry look new. Add a namespace to keep keys from different operations apart. We only compute the key: nothing is stored, remembered, or deduplicated here, and your values are never echoed back.

Everyone rolls their own idempotency key, and the naive version hashes the serialized request body. That breaks the moment a client reorders JSON keys, reformats a number, or adds a timestamp: the retry looks like a new request and the customer is charged twice. Canonicalizing first removes the formatting from the equation, and selecting fields removes the noise.

When to use it

Scope

Non-goals

• Does not store keys, remember them, or deduplicate anything
• Does not decide whether a request is a duplicate — that stays in your store
• Does not echo the payload, the selected values, or the canonical bytes
• Does not encrypt or sign; the key is a digest, not a credential
• Does not accept a caller-supplied key or salt

Properties

Capabilities

Cost & billing

Flat rate per invocation

File handling

How we handle your data

Input schema

Output schema

API contract

curl -sS -X POST "$BASE/v1/execute" -H "Authorization: Bearer $KEY" -H 'Content-Type: application/json' -d '{"skillKey":"workflow.idempotency_key","input":{"payload":{"order":{"id":"A-1001","total":49.9}},"fields":["/order/id"],"namespace":"orders.submit"}}'

import { Squillify } from "@squillify/sdk";

const sq = new Squillify({ apiKey: process.env.SQUILLIFY_API_KEY });

const { output } = await sq.execute("workflow.idempotency_key", {"fields":["/order/id","/order/total"],"namespace":"orders.submit","payload":{"requestedAt":"2026-07-27T10:00:00Z","order":{"id":"A-1001","total":49.9},"traceId":"abc-123"}});

Errors

Other limits

Limitations

• Does not store keys, remember them, or deduplicate anything
• Does not decide whether a request is a duplicate — that stays in your store
• Does not echo the payload, the selected values, or the canonical bytes
• Does not encrypt or sign; the key is a digest, not a credential
• Does not accept a caller-supplied key or salt
• Storing or checking the key — that is your database's job
• Hashing a secret: a digest of a low-entropy secret is guessable
• Keying on data that legitimately changes between retries, such as a timestamp

How to call

POST /v1/execute (requires authentication)

{
  "skillKey": "workflow.idempotency_key",
  "input": {
    "fields": [
      "/order/id",
      "/order/total"
    ],
    "namespace": "orders.submit",
    "payload": {
      "requestedAt": "2026-07-27T10:00:00Z",
      "order": {
        "id": "A-1001",
        "total": 49.9
      },
      "traceId": "abc-123"
    }
  }
}

Examples

{
  "fields": [
    "/order/id",
    "/order/total"
  ],
  "namespace": "orders.submit",
  "payload": {
    "requestedAt": "2026-07-27T10:00:00Z",
    "order": {
      "id": "A-1001",
      "total": 49.9
    },
    "traceId": "abc-123"
  }
}

{
  "encoding": "BASE64URL",
  "selectedFieldCount": 2,
  "canonicalization": "rfc8785-sha256-v1",
  "_meta": {
    "inputBytes": 42
  },
  "key": "IVHiRTS_jRKlqQVe_omAGel4akASJBLBpsIsw7c-7EA",
  "algorithm": "SHA256"
}

{
  "payload": {
    "event": "invoice.paid",
    "invoice": "INV-7"
  },
  "encoding": "HEX"
}

{
  "encoding": "HEX",
  "selectedFieldCount": 0,
  "canonicalization": "rfc8785-sha256-v1",
  "_meta": {
    "inputBytes": 42
  },
  "key": "65cb6d6b2e07352eb26ce145ffe81e49eecee470375abc822089633653bc2270",
  "algorithm": "SHA256"
}

Recommended use cases

• Build an Idempotency-Key for a payment or order submission from the request body
• Deduplicate webhook deliveries whose payload repeats but whose envelope changes
• Give a queue message a stable identity so a redelivery is recognised

Avoid for

• Storing or checking the key — that is your database's job
• Hashing a secret: a digest of a low-entropy secret is guessable
• Keying on data that legitimately changes between retries, such as a timestamp

Related skills

Composable with

Safety & privacy

• Runs without calling any external service.
• Your payloads are never stored permanently.
• Telemetry captures metadata only — never your payload contents.
• We never train models on your payloads.
• No human reviews your payloads.

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