Run a request handler at most once per Idempotency-Key, across replicas. Reserve-then-run against Redis or Postgres, with response replay and fingerprint checking — not check-then-run, which is the bug it exists to prevent.

Stripe-style Idempotency-Key middleware for Hono. IETF draft-ietf-httpapi-idempotency-key-header compliant.

Express middleware for idempotent POSTs via Idempotency-Key with in-flight control and pluggable stores.

Exactly-once idempotency key ledger for retried operations, as a Convex component

Idempotency-key dedup store for the BATCH consumer (Section 23 BATCH)

Idempotency-Key requests: replay the first response, refuse conflicting reuse

Make any operation exactly-once with an idempotency key — replay stored results on retries, safe under concurrency, with optional request fingerprinting. Framework-agnostic, pluggable store, zero-dependency, isomorphic.

Idempotency-Key guard with Drizzle store, scoped keys, lease, Express/Nest/client adapters

Coord-Box — distributed coordination primitives for Node.js: counting semaphores and an idempotency-key registry. Zero runtime dependencies. Pluggable backends (in-memory, Redis) and framework adapters.

Neetru SDK 3.0 — biblioteca runtime universal (browser/Node/Edge) para consumir o ecossistema Neetru. Paths canonical /api/sdk/v1/*, productId obrigatório, Idempotency-Key em mutations, WebCrypto signatures, baseUrl allowlist fail-closed.

Atomic idempotency-key replay for FilamentJS

Client SDK for the Whisk device External API (status, turn, stop) with built-in idempotency-key handling and retry/backoff.

Generic idempotency-key middleware for Express — pluggable storage, no Mongo/Redis dependency baked in. No root export — import only what you need: @desolint/idempotency/config, /services.

Idempotency-key deduplication helper for API handlers — replays the cached result for a repeated key instead of re-running the handler, with TTL-based cleanup.

ISL Standard Library - Idempotency Key Management

Deduplicate retried tool calls by idempotency key, reuse prior results, and prevent duplicate side effects for DeepSeek Harness agents

Idempotency-Key handling to the IETF draft: one execution per key, exact replay, hard conflict on a reused key, atomic claim against concurrent copies. Bring your own store.

Zero-dependency, fetch-first HTTP resilience toolkit: retries with backoff/jitter, per-attempt timeout + total deadline, idempotency-key, interceptor hooks, and standardized errors. Node.js, Bun, browsers.

Idempotency key utilities for duplicate-safe processing and sync retries.

In-process Runtime implementation for @orchestral/core. Submits jobs, dispatches Patterns through a CapabilityRouter, walks the model fallback chain when a call fails, and dedupes by idempotency key. Same-model transient retry and cross-Pattern Alternativ