Prevent duplicate payments, webhook chaos, and retry storms. Learn real patterns used in distributed systems.
A production reliability failure mode: you pay for reasoning, get empty output, and your retry loops do the rest. How to detect it and prevent damage.
Read guide →Learn why Zapier's at-least-once delivery causes duplicates and how to implement idempotency layers to protect your workflows.
Read guide →Stripe webhooks retry on timeouts. Discover how to prevent duplicate payment processing using event IDs and idempotency.
Read guide →Make.com retries failed modules automatically. Learn how to make your scenarios idempotent and retry-safe.
Read guide →AI agents are non-deterministic and retry uncertain operations. Make tool calls idempotent to prevent duplicate side effects.
Read guide →Webhook providers retry on network issues and timeouts. Learn to handle retries safely without creating duplicates.
Read guide →True exactly-once is impossible in distributed systems. Learn the difference between delivery guarantees and processing guarantees.
Read guide →Email API timeouts cause automatic retries. Prevent spam and duplicate notifications with idempotent email sending.
Read guide →Client retries and race conditions cause duplicate database records. Build idempotent APIs that handle retries safely.
Read guide →Button locking isn't enough. Implement server-side idempotency to prevent double-clicks from causing duplicate charges.
Read guide →Modern systems retry. Webhooks resend. APIs race. AI agents repeat. This blog covers idempotency keys, duplicate suppression, and exactly-once effect engineering — the core techniques used to make automation reliable.
Every article includes practical engineering patterns, real code examples, and production-tested solutions — not just theory.
In distributed systems, retries are inevitable. Network timeouts, server restarts, webhook retries, automation platform failures — all of these cause the same request to be processed multiple times. Without idempotency, you get duplicate charges, spam emails, corrupted data, and angry customers.
Idempotency keys solve this by ensuring that processing the same request multiple times produces the same result as processing it once. This is the foundation of reliable automation and payment systems.
Software engineers building payment systems, webhook integrations, automation workflows, AI agents, and distributed systems. If you're working with Stripe, Zapier, Make.com, n8n, or building APIs that need to handle retries safely, these guides are for you.
Idempotency is a property of operations where executing the same action multiple times produces the same result as executing it once. In distributed systems, idempotency keys ensure that duplicate requests (caused by retries, network issues, or user actions) don't create duplicate side effects like double charges or duplicate emails.
Webhook providers like Stripe, Shopify, and GitHub use at-least-once delivery. If they don't receive a fast confirmation from your server (due to network issues, timeouts, or slow responses), they assume the webhook wasn't received and retry sending it. This is intentional behavior to ensure reliability, not a bug.
Use idempotency keys when making Stripe API calls. Stripe supports idempotency keys on all POST requests. Send a unique key (like a UUID or transaction ID) in the Idempotency-Key header. If the request is retried with the same key, Stripe returns the cached result instead of processing it again.
Zapier uses at-least-once delivery and automatically retries steps that timeout or fail. If a step appears to fail (slow response, network issue, or 5xx error), Zapier retries it. To prevent duplicate actions, you need to implement idempotency in your API endpoints that Zapier calls.
True exactly-once processing is impossible in distributed systems due to network unreliability. What most systems call exactly-once is actually at-least-once delivery combined with idempotent processing. This means messages may be delivered multiple times, but idempotency ensures they're processed only once.
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