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Catch the mistakes before your audience does.

Preview your campaign on real email clients, audit its content and accessibility, and check inbox placement. Test the email your platform actually sends before the main launch.

Start testing for freeExplore campaign QA
Gmail, Yahoo and Outlook on a laptop, phone and tablet

Trusted by teams at

  • Broadcom
  • Scraper
  • Trivago
  • Avast
  • Wolt
  • Panasonic
  • Broadcom
  • Scraper
  • Trivago
  • Avast
  • Wolt
  • Panasonic

Make it look right where customers read it.

A layout that works in Gmail can break in Outlook. Compare the delivered campaign across clients like Gmail, Outlook, Yahoo and Apple Mail on phones, tablets and desktop.

Check the full email for cropped images, awkward spacing, hidden buttons and client-specific changes before you approve the design.

Explore device rendering
Desktop, phone and tablet showing light and dark email symbols
Apple and Android phones

Review mobile and desktop

Compare supported iPhone, iPad, Android, macOS, Windows and browser targets. Check the screens and email apps your audience uses.

Light and dark envelopes with sun and moon symbols

Catch dark-mode surprises

Compare available light and dark targets. Find disappearing logos, lost text contrast and buttons that become hard to read.

HTML and EML email files

Check the final HTML

Inspect the message that arrived after your ESP applied its template, personalization and tracking. Review stored email or import an EML file.

Protect every link, image and first impression.

A polished design can still hide a broken link, missing image or unfinished greeting. Run Email Audit on the delivered message to find resource failures, unresolved personalization, spelling and HTML issues.

Use the weighted health score and prioritized findings to decide what to fix first. Open the evidence, correct the campaign in your ESP and send another test.

Explore Email Audit
A broken link beside an image symbol, representing campaign resource checks

Make your email easier for everyone to read.

Bring accessibility into the campaign review. Flag missing alt attributes and document language, unnamed links and table semantics that need attention.

Then review contrast, zoom, image blocking and screen-reader reading order in the target email apps. Use the findings to support your accessibility process alongside the standards relevant to your organization.

Explore accessibility checks
WCAG, ADA, Section 508 and EN 301 549 accessibility references

Accessibility references for your review; automated checks do not establish certification or compliance.

Check where the campaign lands, too.

Your send report and your recipient's inbox tell different stories. Test the actual campaign through your normal sending platform and see inbox, Promotions, spam and not-received outcomes.

Keep placement separate from rendering and content checks. Compare providers, investigate sender findings and test again after making changes.

Explore inbox placement testing
An email with inbox, Promotions and spam outcomes beside provider logos
Yahoo, Gmail, Outlook, Proton Mail and iCloud logos

Test personal inboxes

Check supported Gmail, Yahoo, Outlook.com, Proton Mail and iCloud accounts before sending to consumer audiences.

Microsoft and Google Workspace logos

Test business inboxes

Include Google Workspace and Microsoft 365 to see how business filtering affects the same campaign.

Authentication and blocklist checks for a sending domain

Investigate the sender

Review SPF, DKIM, DMARC and blocklist findings alongside placement. Keep watching the domain between campaigns.

Explore deliverability monitoring

See a delivered campaign through your customer's eyes.

Follow the device-preview workflow from a test email to a set of client renders. Compare the same delivered message and keep the result ready for the people reviewing your campaign.

Follow the rendering guide

Keep the platform. Improve the send.

Test Mailchimp campaigns, Klaviyo flows, Braze journeys, HubSpot emails and more. Send from your existing platform so you can review the final message it produces.

Choose render targets and copy the generated address, or send to a MailSlurp inbox for an audit. For placement, use the test's seed addresses and tracking instructions.

Find your platform guide
HubSpot, Brevo, Mailchimp and Klaviyo sending-platform logos

Make campaign QA part of every release.

Use MailSlurp APIs and SDKs to trigger device renders, audit delivered messages and retrieve placement results. Connect the checks to your campaign tools, template builds or CI pipeline.

Choose the findings that should stop a release, save the results and share them with reviewers. Keep recurring campaigns under review with checks for changed links, images and templates.

Explore the API reference
MailSlurp API and SDK programming languages

Campaign quality assurance questions

What should I check before sending an email campaign?

Preview the delivered message on the clients and devices your audience uses. Audit links, images, personalization, HTML and accessibility. Then run an inbox placement test through your actual sending platform. MailSlurp keeps rendering, content and placement results available for your team to review before launch.

Can I test campaigns from my existing ESP?

Yes. Send test emails from platforms such as Mailchimp, Klaviyo, HubSpot, Braze, Brevo, Salesforce and more. For device rendering, choose the clients and send to the generated render address. For an audit, send to a MailSlurp inbox. A placement test supplies a separate seed list and tracking instructions. Find your ESP guide.

Which email accessibility checks can I run?

Email Audit flags missing alt attributes and document language, unnamed links and table semantics that need review. Combine these findings with manual checks of color contrast, zoom, image blocking and screen-reader reading order in target clients. These checks support an accessibility review; automated results alone do not establish WCAG conformance or legal compliance. Read about Email Audit.

Does a good-looking preview mean the email will reach the inbox?

A preview shows appearance in the selected client. An inbox placement test separately records where the email lands in real seed accounts, including inbox, Promotions, spam and not-received outcomes. Use both to check the customer experience from delivery to reading and clicking.

Can I automate campaign QA with an API?

Yes. Use MailSlurp APIs and official SDKs to run device previews, audit delivered messages, create inbox placement tests and read their results. Connect those checks to template builds, campaign tools or CI, then apply the pass/fail rules your team needs. Explore the API reference.

How can my team review results and keep checking recurring campaigns?

Share device-preview links and saved reports so reviewers can inspect the same email. Fix the campaign in your ESP, send another test and compare the results. For ongoing campaigns and lifecycle messages, Campaign Probe can monitor links, images and template changes between launches. Explore Campaign Probe.

Give your team confidence in the next send.

Start free with a real campaign. Preview it, audit it and check placement, then share the results before the main send.

Check your campaign for free
Slack and Microsoft Teams for sharing campaign results with reviewers