Know what your
email is telling you.

Send one message through your usual platform. See the authentication and content evidence, then choose one useful change for the next send.

Start with your message.

Send through the platform you already use. Read the authentication, content and spam findings in one report.

Test an email

Check your foundations.

Inspect your SPF, DKIM, DMARC and BIMI records. Understand each finding before changing your DNS.

Explore the tools

Make the knowledge yours.

Build practical email skills with step-by-step lessons, useful guides and answers to common questions.

Visit the Academy

Your next send starts here

One email.
A practical next step.

Create a test address and send a sample email. Your report will help you understand the checks and decide what to improve.

Use a sample without sensitive information. Anyone with its report link can view the limited results until expiry.

Looking for a specific check? Explore the tools
01Send your emailUse the platform you already send from. 02Read your reportSee each finding and its explanation. 03Improve your next sendMake one change, then test again.

Choose your starting point

Nine tools. A check for each question.

Investigate a domain, an email address or a sending IP. Open a service to see what it checks and get started.

Inside your email report

Understand the finding.
Choose your next fix.

A score is a starting point. The individual checks help you understand what happened to your message and where to investigate next.

Authentication

See the SPF, DKIM and DMARC findings for the message you sent, including the identities used to authenticate it.

Content and structure

Review the subject, message structure and link findings. Follow up on the specific issues highlighted in your results.

A focused retest

Make one change, send a fresh message through the same platform and compare the relevant findings.

See how message testing works

For the people behind the send

Make testing part of your workflow.

Whether you send campaigns, build transactional emails or look after client domains, start with a repeatable check.

01 / MARKETERS

Check the campaign before you send.

Send a sample from your usual platform. Review its authentication and content findings while there is still time to make a change.

Test a campaign email
02 / DEVELOPERS

Investigate the emails your app sends.

Test a receipt, signup message or password reset. Follow the sending identities, inspect DNS records and bring checks into your integration.

Explore API and MCP setup
03 / AGENCIES

Give every client a consistent checklist.

Work through authentication and reputation checks for the domains you manage. Retest after a DNS change or a move to a new sending platform.

Find the right checks

Built for your application and your agent

Bring email checks into the way you work.

Call the REST API from your server, or connect Cursor, Claude Code or another compatible MCP client. Use your own API key with the permissions and allowances attached to your account.

Estimate your API costs

“Check fintrate.com’s SPF and explain what needs fixing.”

  1. 1

    Choose an available service

    Check access and remaining allowance.

    list_services
  2. 2

    Start the check

    Submit the domain with a unique request identifier.

    check_spf
  3. 3

    Read the result

    Retrieve the findings and discuss the next step.

    get_check_result

Learn it. Check it. Put it to work.

A practical place to build your email skills.

Explore the Academy

Before your first test

A few questions,
answered.

Start here, or visit the FAQ for more help with tests, authentication and your account.

Browse all FAQs
Do I need an account to test an email?

You can start a message test on the website without an account. Create an account to manage API keys, view your workspace and use services included in your plan.

Should I send an email or use a domain checker?

Send a message when you want to inspect what your sending platform actually produces. Use a domain checker when you want to investigate a specific published setting, such as an SPF policy or DKIM key.

Does a good score guarantee inbox delivery?

No. The score summarises the checks performed on that message. Use the individual findings to investigate problems; recipient filters, sender reputation and subscriber behaviour also affect delivery.

Does Email Verifier prove that a mailbox exists?

No. It checks the address format and the domain’s mail routing. It does not contact the recipient’s mailbox or confirm that a future message will be accepted.

Can I use Deliverlens in my application or AI agent?

Yes. Use a named API key for the REST API, or connect a compatible MCP client such as Cursor or Claude Code. The same account permissions, API limits and service allowances apply.

How much does testing cost?

Visit pricing to compare the testing options and estimate API costs. Your account shows the service allowances attached to your current plan.

Your next send starts here

Start with one email.

Send it through your usual platform. Read the findings. Decide what to improve.

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