Free email tools

Check a domain

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

Generate a record

• SPF record generator: Build an SPF record from the services and servers that send your mail, with every term explained.
• DMARC record generator: Build a DMARC record with the policy, reporting and alignment settings you choose, each one explained.

Write and preview

• Email 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: 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: 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 lists every parameter.

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.