Source: https://once-email.com/developers

Developer documentation

Developer documentation Overview

# Once Email developer platform

Build reliable email test workflows

One place for the API contract, seven SDK ecosystems, versioned downloads, demos, and the open-source email test Skill.

[Start with the API](<https://once-email.com/api>) [Browse source](<https://github.com/pangxin12345/once-email-sdks>)

## Choose how you build

[### API Public documentation · controlled access Learn authentication, inbox operations, errors, limits, retries, and cleanup for authorized systems. Read documentation](<https://once-email.com/api>) [### SDK Seven versioned prerelease SDKs Download, verify, and build a fixed SDK release for the language already used by your test service. Read documentation](<https://once-email.com/sdk>) [### Skill Open-source prerelease download Add one bounded test to an authorized project, return redacted evidence, and always clean up. Read documentation](<https://once-email.com/skill>)

Recommended workflow

## From contract to one clean test

Use one deadline and one uniquely marked message, then always clean up. Once Email receives mail only and does not automate third-party registration.

1. 1

   Confirm ownership or explicit authorization, then choose API, SDK, or Skill for the existing test stack.
2. 2

   Keep the API key in a process secret facility; verify every downloaded archive before use.
3. 3

   Run one bounded workflow and delete the temporary inbox in finally on success or failure.

## Documentation and resources

[API quickstart](<https://once-email.com/api>) [SDK downloads and checksums](<https://once-email.com/sdk>) [Browse source](<https://github.com/pangxin12345/once-email-sdks>) [Practical testing guide](<https://once-email.com/blog/temporary-email-api-testing-guide>)