# Idempotency

> Idempotency is the property of an operation that produces the same result whether it runs once or several times. In integrations, an idempotent step checks whether its work was already done, often using a unique key such as an order or event ID, before acting. This makes it safe to retry failed requests or process duplicate webhooks without creating duplicate records, charges or emails.

## Why it matters for your business

Retries and duplicate events are normal in automation. Webhooks get redelivered, network calls time out after the receiving system already acted, and workflows get rerun after an error. Without idempotency, each of those can create a second invoice, a double payment or a repeated customer email. Asking whether a workflow is idempotent is one of the most useful technical questions a buyer can ask, because it separates automations that recover cleanly from ones that need someone to clean up duplicates by hand.

## Example

An automation creates a bill in the accounting system for each approved vendor invoice. During an outage, the accounting API accepts a request but times out before replying, so the workflow retries. Because the workflow first searches for an existing bill with the same vendor and invoice number, the retry finds the bill already created and skips it instead of recording the invoice twice.

Related terms: https://www.lumeor.studio/glossary/webhook/, https://www.lumeor.studio/glossary/api-application-programming-interface/, https://www.lumeor.studio/glossary/workflow-automation/, https://www.lumeor.studio/glossary/rate-limiting/

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Source: https://www.lumeor.studio/glossary/idempotency/