WhatsApp error 1: API Unknown

Code 1 is the Graph API's catch-all. Meta is telling you that the request could not be processed, and that it is either malformed in a way no more specific validator caught, or that something went wrong on the server side. The message deliberately hedges between the two, which is what makes this code frustrating: the same number covers a typo in your JSON and an upstream incident.

In practice, on the WhatsApp Cloud API code 1 most often shows up in two contexts. The first is a transient platform problem, where a batch of sends fail with code 1 for a few minutes and then recover without any change on your side. The second is a structurally bad request body that the parser rejected before it could identify a specific field, such as an object where an array was expected.

Nothing about this code says your token is wrong, your template is missing, or the recipient is invalid. Those conditions all have their own codes.

Validate outbound payloads against a schema for each message type before they leave your service, so structural mistakes are caught locally instead of as code 1. Wrap sends in a retry policy that distinguishes transient failures (retry with backoff, cap at a few attempts) from deterministic ones, and alert when the code 1 rate spikes across many recipients, which usually means a platform incident rather than your bug. Compare code 2 (explicit downtime) and 131000 (the WhatsApp layer's unknown error); the retry-policy table in the error-code guide covers all three.