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How signed conversion postbacks and refunds work

Sign the exact request bytes, reuse a stable external conversion ID, and send refunds to the refund endpoint so commission reverses idempotently.

Published Jul 14, 2026 · Last reviewed Jul 14, 2026

Conversion

Your server sends POST /v1/conversions with integer minor units, currency, a stable externalId, and an affiliate click or code. Sign timestamp-dot-raw-body with HMAC-SHA256 and send the surface, timestamp, and signature headers.

Use Unix seconds and a fresh timestamp.
Sign the exact bytes you send.
Keep the secret server-side.
Retry with the same externalId so duplicates remain safe.

Refund

Send POST /v1/conversions/refund with the original externalId, a stable refundId, refunded minor units, and matching currency. Full and partial refunds reverse the corresponding commission on the same ledger.

What this does not do

A signed postback proves the configured server sent the event. It does not validate an unsigned browser claim, replace your order system, or make floating-point currency safe.