In short
Social Relay requires an Idempotency-Key header on POST /api/v1/posts so network retries do not double-charge tokens or double-publish. Keys are 8–128 characters and scoped to the platform account.
Rules
- Required on create post
- 8–128 characters; safe alphabet for HTTP headers
- Same key + same platform returns original result
- Do not reuse a key for a different body intent
Client patterns
Generate a UUID per user click. On timeout, retry with the same key until you get a definitive response. For a new user edit, use a new key.