Build an idempotency key from an event

Join a scope, a business id and a version into one stable, colon-separated key.

JavaScript Version 1.0.0 · MIT · by Oveyon · .md

function idempotencyKey({ scope, id, version }) { return [scope, id, version].map(part => encodeURIComponent(String(part))).join(':'); }

Input & expected output

{
  "scope": "order-confirmation",
  "id": "8812",
  "version": 1
}

"order-confirmation:8812:1"

The edge case

{
  "scope": "welcome",
  "id": "user:42",
  "version": 2
}

"welcome:user%3A42:2"

Know the limits

• Derive the key from the business event, never from time or randomness: a retry must send the same key.
• Oveyon accepts 1–190 printable ASCII characters without spaces, as the Idempotency-Key header or the idempotencyKey body field. Encoding keeps every part inside that set.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Convert an email domain to punycode — Keep the local part and convert an international domain to its ASCII xn-- form.
• Get the domain of an email address — Take the part after the last @ and lowercase it, for domain checks and grouping.
• Mask an email address for logs — Keep the first character and the domain; hide the rest of the local part.