# Free Email Tools: SPF, DKIM, DMARC and Domain Checks

> Free email tools with no sign-up: check SPF, DKIM, DMARC, MX, BIMI and blocklists, build SPF and DMARC records, test subject lines and preview HTML email.

Canonical page: https://sendly.now/tools

1. [Home](/)
2. Free tools

Free tools

# Free email tools

Free email tools with no sign-up: check SPF, DKIM, DMARC, MX, BIMI and blocklists, build SPF and DMARC records, test subject lines and preview HTML email.

Last updated 2026-10-26

## Check a domain

- [Email domain health check](/tools/domain-health): Check SPF, DKIM, DMARC, MX and BIMI for a domain in one read, with the exact fix for each problem.
- [SPF record checker](/tools/spf-checker): Validate a domain's SPF record and count its DNS lookups across every include against the limit of 10.
- [DKIM record checker](/tools/dkim-checker): Look up a domain's DKIM public key by selector and check its type, size and flags.
- [DMARC record checker](/tools/dmarc-checker): Check a domain's DMARC policy, reporting addresses and coverage, including subdomain inheritance.
- [MX record lookup](/tools/mx-lookup): List a domain's mail servers in priority order, resolve each one and identify the mail provider.
- [BIMI record checker](/tools/bimi-checker): Check whether a domain's BIMI logo can show in inboxes: the record, DMARC enforcement and the certificate.
- [Email blocklist check](/tools/blocklist-check): Check a mail server's IPv4 address, or a hostname's addresses, against public DNS blocklists.

## Generate a record

- [SPF record generator](/tools/spf-generator): Build an SPF record from the services and servers that send your mail, with every term explained.
- [DMARC record generator](/tools/dmarc-generator): Build a DMARC record with the policy, reporting and alignment settings you choose, each one explained.

## Write and preview

- [Email subject line tester](/tools/subject-line-tester): shows where phones and desktops cut a subject and preheader, and flags merge tags that did not render, shouting and spammy habits.
- [Email signature generator](/tools/email-signature-generator): builds a table-based HTML signature with inline styles that Gmail, Outlook and Apple Mail render alike, plus a plain-text version.
- [HTML email preview](/tools/email-preview): your email at phone and desktop widths, with images on or off, in your browser.

## Use them from code or an AI agent

Every tool is a GET request with no account and no key, answering JSON, or Markdown with `Accept: text/markdown`. Each address may make 30 calls a minute and 300 a day. The [OpenAPI description](https://sendly.now/api/tools/openapi.json) lists every parameter.

Example

```
curl "https://sendly.now/api/tools/domain-health?domain=example.com"
```

## When a call fails

A failed call answers an RFC 9457 problem document (`application/problem+json`). Its `code` is one of the values below, and its `type` links to that row of this page.

| Code                 | Status | Meaning                                                                                                |
| -------------------- | ------ | ------------------------------------------------------------------------------------------------------ |
| invalid\_input       | 400    | The tool cannot use the input. The detail says why.                                                    |
| unknown\_tool        | 404    | No free tool has that name. The list is on this page.                                                  |
| method\_not\_allowed | 405    | The tools answer GET and HEAD, and OPTIONS for a CORS preflight.                                       |
| rate\_limited        | 429    | More than 30 checks a minute or 300 a day from one address. Retry-After says how many seconds to wait. |

Something on this page out of date, or missing the case you are in? Write to [support@sendly.now](mailto:support@sendly.now) — we answer our own email. The full technical detail lives in the [documentation](https://docs.sendly.now).