Email — entry 016 of 19
PostStack
PostStack is an EU-hosted transactional and marketing email API covering sending, contact management, domain verification, and broadcast campaigns, authenticated with a Bearer API key or OAuth token and keeping all data inside the EU. Its free tier covers 3,000 emails a month before metered paid plans apply.
AuthenticationAPI KeySign up with the provider to obtain credentials.
HTTPSSupportedTraffic is encrypted in transit.
CORSDisabledBrowser calls need a server-side proxy.
PricingFreemiumA usable free tier exists, with paid plans for more volume.
FormatsJSONResponses can be requested as JSON.
GreatAPIs Score
Score61
Authentication15/25API key required
Pricing17/20Freemium tier available
Docs0/20No docs or spec available
Formats9/15Single response format
Freshness20/20Verified within 6 months
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<a href="https://greatapis.com/api/poststack/"><img src="https://greatapis.com/badge/poststack.svg" alt="Scored 61 on greatapis.com"></a>Auth quickstart
- Sign up with the provider to get an API key.
- Send it on every request as a header
Authorization: <key> - The exact header isn't documented — Authorization is a common default; confirm in the provider's docs.
Stored keyNo key stored
Your key is stored only in this browser (localStorage) and sent directly to the API — never to greatapis.