# Once Email

> Create a free temporary address for receiving messages and verification codes without exposing your regular inbox. Receive only; no sign-up required.

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

## Pages

- [Free Disposable Email](https://once-email.com/index.md): Create a free temporary address for receiving messages and verification codes without exposing your regular inbox. Receive only; no sign-up required.
- [Temporary email questions, answered](https://once-email.com/faq.md): Once Email creates temporary addresses for receiving messages and verification codes without registration. It cannot send email. Review these answers before using a temporary address for a service.
- [Once Email API](https://once-email.com/api.md): Public developer documentation for automated email testing: authentication, quotas, errors, and safe-use rules.
- [Once Email SDKs](https://once-email.com/sdk.md): Open-source SDK candidates for the Once Email receive-only API, with tested downloads for seven ecosystems.
- [Once Email Skill](https://once-email.com/skill.md): Design safe, auditable agent workflows for email flows you own or are authorized to test. This page documents the boundary without claiming unreleased clients are available.
- [Unpack nested archives without losing control](https://once-email.com/unpack-flow.md): Download the verified UnpackFlow command-line package for Linux, macOS, or Windows—or install the complete Codex Skill for guided, observable archive work.
- [Once Email developer platform](https://once-email.com/developers.md): Build authorized email test workflows with the Once Email API, seven SDKs, and the open-source test-email-flows Skill.
- [About Once Email](https://once-email.com/about.md): Learn what Once Email does, how the receive-only temporary mailbox works, and the limits we apply to protect users.
- [Contact Once Email](https://once-email.com/contact.md): Contact Once Email for support, privacy questions, security reports and abuse reports.
- [Once Email Privacy Policy](https://once-email.com/privacy.md): How Once Email handles temporary mailbox, account, billing, technical log, browser-local tool and privacy-request data.
- [Once Email Terms of Service](https://once-email.com/terms.md): Rules for the free receive-only mailbox, browser-local tools and optional paid API subscriptions offered by Once Email.

## Guides

- [Why Once Email Is Receive-Only by Design](https://once-email.com/blog/helloworld.md): A factual introduction to Once Email, the problems a temporary inbox can solve, the cases where it should not be used, and the safety boundaries behind the service.
- [Verification Email Not Arriving? A Safe Troubleshooting Checklist](https://once-email.com/blog/anxiety.md): Work through address mistakes, sender delays, retries, filtering and mailbox limits without repeatedly requesting codes or weakening account security.
- [How Long Does a Temporary Email Last? Plan Before It Expires](https://once-email.com/blog/readbook.md): Understand Once Email lifetime choices, deletion and replacement, then decide what to save and when an account needs a permanent recovery address.
- [How to Inspect Email Links and Tracking Pixels Without Opening Them](https://once-email.com/blog/inspect-email-links-tracking-pixels.md): Review email HTML locally for dangerous schemes, nested redirects, misleading domains, remote images and tracking-pixel clues without rendering the message.
- [Postfix vs Dovecot: Different Roles in a Receiving Email Server](https://once-email.com/blog/corecomponent.md): See where Postfix and Dovecot sit in the inbound mail path, what each service owns, how LMTP connects them, and which evidence to check when delivery fails.
- [How to Read SPF, DKIM and DMARC Results in an Email Header](https://once-email.com/blog/read-spf-dkim-dmarc-results.md): Understand what SPF, DKIM and DMARC authenticate, why alignment matters, and why a pass result is useful evidence rather than proof that a message is safe.
- [Once Email Editorial and Review Policy](https://once-email.com/blog/editorial-policy.md): How Once Email selects topics, verifies product claims, cites sources, handles translations, records updates and corrects published guidance.
- [Email Testing Checklist for Developers: From Request to Expiry](https://once-email.com/blog/email-testing-checklist.md): A practical, authorised checklist for testing sign-up, verification and password-reset email flows without masking delivery defects or weakening security controls.
- [How to Save Email Test Evidence Without Exposing Secrets](https://once-email.com/blog/safe-email-test-evidence.md): Create useful screenshots, headers and bug reports while removing verification codes, reset tokens, email addresses, identifiers and unrelated personal data.
- [Email Alias vs Temporary Inbox vs Permanent Address: Which Should You Use?](https://once-email.com/blog/email-address-types.md): Compare forwarding aliases, receive-only temporary inboxes and permanent email accounts by recovery, privacy, replies, record keeping and website policy.
- [Why Some Websites Reject Disposable Email Addresses](https://once-email.com/blog/why-sites-reject-disposable-email.md): Understand the account-recovery, abuse, support and risk reasons behind disposable-email restrictions—and what legitimate users should do instead of evading them.
- [How to Read Received Headers and Trace an Email Delivery Path](https://once-email.com/blog/read-received-headers.md): Follow Received header fields in the correct order, compare timestamps safely and recognise the limits of hostnames, IP addresses and untrusted trace data.
- [A Safe Checklist Before Downloading an Email Attachment](https://once-email.com/blog/attachment-safety-checklist.md): Check the request, sender, file name, type and handling environment before downloading an attachment—and know what email previews and scanners cannot prove.
- [Batch-download Email Attachments and Unpack Them Locally with UnpackFlow](https://once-email.com/blog/batch-email-attachments-unpackflow.md): Use a dedicated folder, verify every browser download, then list, plan and unpack multipart or nested archives locally without uploading them to an online service.
- [A Privacy-First Decision Tree for Email Sign-Ups](https://once-email.com/blog/privacy-first-email-decision-tree.md): Choose between a permanent address, forwarding alias and temporary receive-only inbox by checking recovery, payments, records, replies and website policy.
- [Temporary Email Threat Model: What It Protects and What It Does Not](https://once-email.com/blog/temporary-email-threat-model.md): Model the assets, adversaries, protections and limits of a receive-only temporary inbox without confusing address separation with anonymity or message safety.
- [Email Verification Codes: A Safer Way to Copy, Check and Use Them](https://once-email.com/blog/email-verification-code-safety.md): Treat an email verification code as a short-lived secret: confirm the request, inspect the destination, copy only the code and clear it when the task is finished.
- [How to Use a Temporary Email API Without Building Flaky Tests](https://once-email.com/blog/temporary-email-api-testing-guide.md): A practical design for temporary-email API tests: isolate each run, poll with backoff, identify the right message, protect secrets and always clean up.

## Languages

- [zh-CN](https://once-email.com/zh_cn/llms.txt)
- [es-ES](https://once-email.com/es/llms.txt)
- [pt-BR](https://once-email.com/pt/llms.txt)
- [de-DE](https://once-email.com/de/llms.txt)
- [fr-FR](https://once-email.com/fr/llms.txt)
- [ja-JP](https://once-email.com/ja/llms.txt)
- [ko-KR](https://once-email.com/ko/llms.txt)
- [id-ID](https://once-email.com/id/llms.txt)
- [vi-VN](https://once-email.com/vi/llms.txt)