Request and response format - Zahlo Merchant Developer Docs

All merchant API requests use JSON under /api/v1. Resource IDs are opaque strings. Timestamps are ISO 8601 UTC values. Amounts are integer minor units paired with a three-letter currency code.

Request headers

Content-Type: application/json
x-api-key: $ZAHLO_API_KEY
Idempotency-Key: order-1001-checkout

Use x-api-key only on the server. Use a bearer client token only for browser access to the session it belongs to. The API may return a requestId; retain it in safe operational logs.

Response envelope

Successful resource responses contain the resource object. List responses contain data, hasMore, and nextOffset where applicable. Errors contain error, message, optional field details, and requestId.

Null, omission, and updates

An omitted field keeps its default or existing value. A field explicitly accepted as null clears it only where the operation documents that behavior. Patch requests should contain only fields the merchant intends to change.

Versioning

Keep the /api/v1 path and use the documented API version header when the environment requires one. Treat unknown response fields as forward-compatible and do not break parsing when new fields appear.