Test keys.

Create a test key

An organization admin selects Test key when creating a key in Developers > API keys. Grant email:send and store the returned pw_test_ key in PRAWNWIRE_API_KEY for the example.

Test keys are scoped to an organization. The generic POSTMARK_API_TEST token does not work.

What a test proves

The same authentication, scope, suspension, message validation, verified-domain, hosting, suppression, monthly allowance and daily-cap checks run as for a live send.

A successful test returns HTTP 200, ErrorCode: 0, Message: "Test job accepted", and a generated MessageID. It does not enqueue a message or increment recipient counts. Rate limits still apply.

What a test does not prove

No SMTP submission happens. A test does not prove DKIM signing, DNS health, delivery, inbox placement, or how a receiving client renders the message.

The generated MessageID is not stored and cannot be fetched from activity. Looking it up returns ErrorCode 701. A test batch checks every message against the current allowance without reserving capacity between entries, so it does not prove the equivalent live batch will fit.

When only some recipients are suppressed, test sends still answer Test job accepted; unlike a live response, that message does not enumerate the skipped addresses. Read suppressions if you need to check them.

Scope still matters

Test keys are not separate organizations or read-only credentials. Their no-send behavior applies to the email endpoints. A test key with email:send can still delete suppressions, and one with read scopes can read the organization’s data.

Go live

Switch to a live key only after checking the request. Send to an address you control, keep the real MessageID, and inspect message details and delivery events.