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Once Email SDKs

Open-source SDK candidates for the Once Email receive-only API, with tested downloads for seven ecosystems.

View source Download prerelease Read the API contract Read the SDK testing guide

7 Once Email SDKs

Use one reviewed OpenAPI contract from TypeScript, Python, Java, Go, .NET, PHP, or Ruby. Source, reference documentation, versions, and local-download archives are public.

TypeScript Python Java Go .NET PHP Ruby

Linux · macOS · Windows

Native CI has passed on Linux, macOS, and Windows. TypeScript and Python include automated tests; Java, Go, .NET, PHP, and Ruby pass their available native build or syntax gates.

Release status

These are public prerelease candidates, not npm, PyPI, Maven Central, NuGet, Packagist, or RubyGems releases. Pin the archive version and verify SHA256SUMS before use.

Every archive includes code and documentation. The release also provides MANIFEST.txt and SHA256SUMS.

Choose an SDK

Use the language already owned by your test service. Do not add a second runtime only for mailbox polling; the seven clients share the same receive-only contract.

Verify before installing

Download one immutable archive, compare its SHA-256 value with SHA256SUMS, read its bundled README and pin the version in your project.

Keep the workflow bounded

Create one inbox per authorized test, poll within one deadline, treat 429/503 separately, avoid logging messages or codes, and always delete the inbox in finally.