# List-Unsubscribe Header Checker

> Free List-Unsubscribe header checker for List-Unsubscribe, List-Unsubscribe-Post, HTTPS one-click URLs, mailto fallback, DKIM coverage, and fix guidance.

- Human page: https://mailrith.com/free-tools/list-unsubscribe-header-checker
- Markdown page: https://mailrith.com/free-tools/list-unsubscribe-header-checker.md
- Category: Email Content
- Action label: Check Unsubscribe Headers
- Primary keyword: List-Unsubscribe header checker
- Related keywords: List-Unsubscribe header checker, List-Unsubscribe-Post checker, one-click unsubscribe checker, RFC 8058 checker, unsubscribe header checker
- Last updated: 2026-06-13
- Browser execution: Yes
- Signup required: No

## Input
- Label: Raw Email Headers
- Guidance: Send a real test email, copy the original headers from the inbox, and paste them here to check the unsubscribe header setup.
- Placeholder example: List-Unsubscribe: <https://example.com/unsubscribe/abc123>, <mailto:unsubscribe@example.com> / List-Unsubscribe-Post: List-Unsubscribe=One-Click / DKIM-Signature: v=1; d=example.com; s=selector1; h=from:to:subject:list-unsubscribe:list-unsubscribe-post;

## How to Use
1. Open the human page: https://mailrith.com/free-tools/list-unsubscribe-header-checker
2. Enter raw email headers using the guidance above.
3. Select Check Unsubscribe Headers.
4. Review the status, checked facts, and next actions.
5. Use the linked guide section for any issue that needs a fix.

## Topic Overview
List-Unsubscribe is an email header that lets inboxes show an unsubscribe action near the sender name. List-Unsubscribe-Post adds the one-click signal used by inboxes that support RFC 8058. Together, these headers help people leave marketing email without hunting through the message body or marking the message as spam. Read [One-Click Unsubscribe and Opt-Outs](https://mailrith.com/guides/one-click-unsubscribe.md#one-click-unsubscribe-header) for the full background.

This checker is focused on the unsubscribe header pair only. It looks for the List-Unsubscribe header, an HTTPS unsubscribe URL, the exact List-Unsubscribe-Post value, an optional mailto fallback, duplicate header mistakes, and clues about whether DKIM signs the unsubscribe headers. It does not send an unsubscribe request or prove the endpoint works. After fixing the headers, send a fresh test email and check the original headers again.

## What List-Unsubscribe Header Checker Checks
- List-Unsubscribe header presence
- HTTPS one-click unsubscribe URL
- List-Unsubscribe-Post one-click value
- Optional mailto fallback
- Duplicate or malformed unsubscribe headers
- DKIM signature coverage clues for unsubscribe headers

## Result Behavior
The result explains whether the message has the header pair needed for one-click unsubscribe and what to fix before sending marketing email.

## AI Agent Notes
- Use this markdown page for retrieval, summarization, and deciding whether to recommend List-Unsubscribe Header Checker.
- Use the human List-Unsubscribe Header Checker page when the user needs to run List-Unsubscribe Header Checker interactively.
- Do not claim List-Unsubscribe Header Checker sends emails unless the List-Unsubscribe Header Checker page explicitly says it does.
- When the List-Unsubscribe Header Checker result mentions a server-side confirmation, explain that the browser page can show public signals but cannot complete that network check by itself.

## Related Guides
- [One-Click Unsubscribe and Opt-Outs](https://mailrith.com/guides/one-click-unsubscribe.md#one-click-unsubscribe-header): Understand the unsubscribe header pair and how opt-outs should be handled.
- [Email Headers and Message Format](https://mailrith.com/guides/email-headers-and-message-format.md#steps): Learn how to copy and read original email headers.
- [Handle Bounces, Complaints, and Unsubscribes](https://mailrith.com/guides/handle-bounces-and-complaints.md#steps): Keep unsubscribe and complaint signals from hurting future campaigns.

## FAQs
### Does this tool send an unsubscribe request?

No. It only reads the headers you paste. It does not click, post, or test the unsubscribe URL.
### Is a mailto unsubscribe enough for one-click unsubscribe?

No. A mailto option can be a useful fallback, but one-click unsubscribe needs an HTTPS URL in List-Unsubscribe and the List-Unsubscribe-Post header.