Documentation
Start with the quickstart. The API reference is the contract; if something is documented here and doesn't work, that's a bug and we want to hear about it.
Find what you need.
Quickstart
From nothing to a delivered email. Create a trigger, get a test key, fire one POST.
Start here →REFERENCEAPI reference
Every endpoint that exists, with request and response shapes.
The contract →WEBHOOKSWebhooks
The event list, the signature scheme, and how retries behave.
Events and signatures →RUNBOOKSRunbooks Roadmap
What to do when authentication fails, a domain won't verify, or mail is being refused.
Coming Q3 2026 →Before you start.
No client libraries.REST and a bearer token, which means whatever HTTP client you already have. If we ship libraries we'll say so here first.
Rate limits are generous and unpublished.They exist to stop a runaway, not to shape normal use. We'll publish exact numbers alongside the response headers when those ship — a documented limit with no header to read against it is worse than no limit at all.
Use them without an account.
Public utilities we built for ourselves and shipped because everyone needs them.
Deliverability lookup
Enter any domain. Get its public auth status — SPF, DKIM, DMARC — and its presence on five major blocklists.
Open tool →FREEDMARC analyzer
Paste your DMARC XML. Get a plain-English breakdown of who's passing, who's failing, and what to fix next.
Open tool →FREESpam score checker
Paste a campaign HTML. Get a score and concrete suggestions to improve it.
Open tool →FREERender preview
Paste HTML; preview rendering across Gmail, Outlook, Apple Mail, Yahoo, dark mode, mobile, and image-off.
Open tool →Build first.
Talk to us second.
Get a test key, paste one POST, watch it render. Nothing leaves the sandbox until you swap the key.