Free diagnostics

Free email deliverability tools.

Run focused DNS, authentication, transport-policy, and header checks before you scale a campaign or debug a sending issue.

Run a free check Full deliverability test

free tools

stored submissions

No SMTP

mailbox probing

Use the narrowest diagnostic first

Each free tool answers one concrete question. Use it to confirm publication, spot obvious configuration errors, or gather evidence before running a full message test.

Use MX lookup when inbound routing or null MX publication is unclear.
Use SPF checker before changing sender authorization records.
Use DMARC checker before moving policy toward quarantine or reject.
Use MTA-STS checker when transport-policy publication matters.
Use Header analyzer when you need a private, redacted look at message headers.
Use Blacklist check when you suspect a sending IP or domain is listed.
Use DKIM checker to find and validate signing keys before DMARC enforcement.
Use Sender compliance checker to audit the Gmail and Yahoo bulk-sender rules in one pass.
Use DMARC generator to build a valid _dmarc record for your domain.
Use Email validator before sending to an address or list you have not mailed recently.
Use Deliverability tester to test the full production-like message before launch.

Free tools are diagnostics, not delivery guarantees

A clean DNS record or header block does not prove inbox placement. For production sends, pair these checks with a real-message deliverability test, list validation, domain monitoring, and DMARC reporting.

Free tools

MX lookup

Published MX hosts, priority order, and null MX intent.

Use before debugging inbound routing or validating a domain accepts mail.

Run free check MX records guide

SPF checker

SPF TXT publication, duplicate records, terminal policy, and lookup mechanisms.

Use before changing ESP, CRM, support, or transactional sending records.

Run free check SPF cheat sheet

DMARC checker

DMARC policy, inherited policy, testing mode, and aggregate reporting.

Use before moving from monitoring to quarantine or reject.

Run free check DMARC rollout guide

MTA-STS checker

DNS signal, HTTPS policy fetchability, mode, max_age, and MX patterns.

Use when enforcing SMTP TLS policy or debugging transport-policy publication.

Run free check MTA-STS guide

Header analyzer

Required headers, dates, Message-ID, MIME hints, unsubscribe, and risk signals.

Use when you need private, redacted evidence from a message header block.

Run free check List-Unsubscribe guide

Blacklist check

20+ DNSBLs for a sending IP or domain, decoded return codes, and direct delist links.

Use when mail suddenly gets rejected or you suspect a listing after a campaign.

Run free check Blacklist removal playbook

DKIM checker

Automatic selector finding, key validation, strength estimate, and revocation flags.

Use before DMARC enforcement or after an ESP migration breaks signing.

Run free check DKIM rotation guide

Sender compliance checker

SPF, DKIM, DMARC, PTR, and TLS audited against current Gmail and Yahoo rules.

Use before scaling volume or when Gmail or Yahoo starts deferring your mail.

Run free check Bulk sender rules guide

DMARC generator

Guided wizard that builds a valid _dmarc TXT record for your DNS.

Use when publishing DMARC for the first time or adding rua reporting.

Run free check DMARC rollout guide

Email validator

Syntax, DNS domain, MX, disposable and role signals, SMTP probe, and catch-all status.

Use before sending to an address or list you have not mailed recently.

Run free check Validation statuses guide

Deliverability tester

Real-message test across authentication, DNS, headers, content, links, and score.

Use before a launch, template change, or ESP migration to catch failures early.

Run free check Pre-launch spam check

MX lookup

Check published mail exchange hosts and priority order.

SPF checker

Inspect sender authorization records and common SPF risks.

DMARC checker

Review effective policy, inheritance, testing mode, and reporting.

MTA-STS checker

Validate DNS publication and HTTPS policy fetchability.

Header analyzer

Analyze headers with automatic PII redaction.

Blacklist check

Query 20+ blocklists for an IP or domain with delist links.

DKIM checker

Probe common selectors and validate published signing keys.

Sender compliance

Audit the Gmail and Yahoo bulk-sender rules in one pass.

DMARC generator

Build a valid _dmarc TXT record with a guided wizard.

Email validator

Classify recipient risk with 12-layer validation evidence.

Deliverability tester

Test the real message before launch and get a prioritized fix list.

FAQ

Are these free tools the same as a full deliverability report?

No. They check focused DNS, policy, or header evidence. A full deliverability report uses the actual sent message and evaluates more layers together.

Do the free tools retain submitted domains or headers?

No. The public diagnostics are designed for request-time evidence and no default retention of submitted domains or pasted headers.