UUID Use Case
UUID Idempotency Key
Network retries can double-charge a customer. An idempotency key — a UUID you generate once — lets the server deduplicate repeated calls.
Prevents duplicatesClient-generatedv4
Generated locally with the Web Crypto API — nothing leaves your browser.
What Is UUID Idempotency Key?
- An idempotency key tags a request. If the same UUID arrives twice, the server returns the original result instead of executing again.
- Because the client generates it, a v4 UUID is perfect: unique per logical operation, no coordination needed.
How to generate
- Generate one v4 UUID per user action (e.g. 'submit order').
- Send it as the Idempotency-Key header on every retry.
- Persist the key→result mapping server-side for the retention window.
Use Cases
- Payment charges and refunds.
- Order submissions over flaky networks.
- Webhook deliveries that may repeat.
Code Examples
JavaScript
fetch('/charge', {
method: 'POST',
headers: { 'Idempotency-Key': crypto.randomUUID() },
body: JSON.stringify(payload)
});Frequently Asked Questions
Who generates the idempotency key?
The client, once per logical operation. Reusing the same UUID on retries is exactly the point.
How long should the server remember it?
Long enough to cover the retry window — typically 24 hours to a few days.
Related tools
UUID v1 GeneratorUUID v3 GeneratorUUID v4 GeneratorUUID v5 GeneratorUUID v6 GeneratorUUID v7 GeneratorUUID v8 GeneratorBulk UUID GeneratorShort UUID GeneratorUUID ValidatorUUID FormatterUUID as a Primary KeyUUID Database IDUUID Foreign KeyUUID Shard KeyUUID Partition KeyUUID in a Composite KeyUUID Surrogate KeyUUID API KeyUUID Session TokenUUID Access TokenUUID Refresh TokenUUID Idempotency KeyUUID Request IDUUID Correlation IDUUID Trace IDUUID CSRF TokenUUID NonceUUID FilenameUUID Object KeyUUID S3 KeyUUID Upload IDUUID Cache KeyUUID Blob NameUUID Temp FileUUID User IDUUID Account IDUUID Customer IDUUID Device IDUUID Tenant IDUUID Client IDUUID Anonymous IDUUID Member IDUUID Message IDUUID Event IDUUID Job IDUUID Task IDUUID Queue Message IDUUID Transaction IDUUID Order IDUUID Invoice IDUUID Payment IDUUID Reset TokenUUID Verification TokenUUID Invite CodeUUID API SecretUUID Share LinkUUID Magic LinkUUID Node IDUUID Worker IDUUID Lock IDUUID Cluster IDUUID Test DataUUID Seed DataUUID FixtureUUID Mock IDUUID Placeholder IDUUID Sample ID