Test your next campaign in MailSlurp.

Evaluating Litmus and Email on Acid? Send a test from your usual ESP, catch broken layouts on real clients and devices, then check links and inbox placement before launch.

Start previewing for free See the previews

Gmail, Yahoo and Outlook logos on a laptop, phone and tablet

Trusted by teams at

Looks good in your editor. Does it work in their inbox?

Catch broken layouts, missing images and unreadable buttons before customers open your email. MailSlurp renders the delivered message across Gmail, Outlook, Apple Mail, Yahoo and supported mobile and desktop clients.

Check iPhone, Android, desktop and light or dark mode together. Compare the places your audience actually reads email.

Explore device rendering

Light and dark email symbols alongside phone, tablet and desktop device types

iPhone and Android

Check narrow screens, responsive columns, image scaling and buttons your readers need to tap.

Gmail, Outlook, Yahoo, Proton Mail and iCloud provider logos

Gmail, Outlook and Apple Mail

Compare supported mailbox clients, including Outlook Classic and New Outlook, where the same HTML can look different.

Light and dark email envelopes with sun and moon symbols

Light and dark mode

Spot disappearing logos, low-contrast text and unexpected background colors before you send.

Keep your ESP. Test the email it actually sends.

Build campaigns in HubSpot, Mailchimp, Klaviyo, Brevo or your usual email platform. Send a test to your MailSlurp render address and preview the delivered version, including the images, links and tracking your ESP adds.

Make any correction in the same campaign editor, then send another test. You do not need to move your campaigns or write code.

Find your ESP guide

Send from your email platform

Use a dedicated render address to check the message your provider delivers, not just the editor preview.

HTML and .eml files with an upload arrow

Upload HTML or an email file

Start an earlier design check from HTML, or import an exported .eml file when you already have the message.

An email with repeat arrows for another preview check

Repeat the same client checks

Save a target profile and compare matching clients after a change so a correction is easy to verify.

Check the design, the links and the inbox.

A good-looking email still needs working links and a place in the inbox. Pair device previews with Email Audit and a separate inbox placement test through your sending provider.

Review provider-by-provider placement, investigate sender-domain issues and fix content problems before the campaign goes out.

Explore campaign checks

Gmail, Outlook, Yahoo and other mailbox provider logos

Find broken links and images

Email Audit checks the delivered message for broken links, missing images, unresolved placeholders and other content issues.

Illustration of inbox, Promotions and spam placement

Test inbox placement

See inbox, Promotions, spam and not-received results from the provider mailboxes in your placement test.

SPF, DKIM, DMARC and blocklist checks illustration

Check sender health

Follow authentication and domain findings when SPF, DKIM, DMARC or blocklist issues need attention.

Fit previews around your campaign calendar.

Start free, then use prepaid capacity or pay-as-you-go usage for your campaigns and reruns. Review completed previews as they arrive and get Slack or Microsoft Teams notifications when a run is ready or needs attention.

Share the current result with your team. Use the API when previews need to run automatically alongside your existing tests.

See preview options

Slack and Microsoft Teams logos with a waving hand

A bundle and individual envelopes representing flexible preview capacity

Prepaid or pay as you go

Choose capacity around the number of campaigns, client targets and corrections your team expects to review.

MailSlurp SDK and programming language artwork

API access for repeat checks

Create render runs, retrieve results and connect email previews to your application tests or CI workflow.

An email and hourglass representing a check in progress

Keep work moving

Inspect completed targets while the run progresses. Notifications bring the team back when the results need a review.

Preview delivered emails before customers see them

Review the campaign across supported email clients and configured render targets, compare results, and inspect the source HTML before the campaign reaches customers.

How email previews work

Keep creating campaigns in your usual editor. Check the delivered email in MailSlurp before you send it to customers.

Send a test email

Create a MailSlurp render address and send a test from your email provider. Choose the clients and display modes your audience uses.

Fix what breaks

Review the screenshots for cropped text, missing images and unreadable buttons. Make corrections in your editor, send another test and compare the affected client again.

Share the checked version

Share the current result with your reviewers. Resolve comments after checking each fix, then get your team's sign-off before scheduling the campaign.

Preview emails from your sending platform

Follow the exact test-send workflow for your email service provider.

Kit

Try the review your campaign team needs on a busy launch week.

Take one correction through the whole review

Start with your next newsletter or promotion. Send a test from your normal ESP, choose your audience's clients and inspect desktop, mobile and dark-mode results. Correct a broken layout in the original editor, then resend and compare the same client. Use the HubSpot guide or Mailchimp guide for the send steps.

Match preview capacity to the way you work

Count the campaigns, client targets and reruns your team expects. MailSlurp offers prepaid capacity and pay-as-you-go usage alongside API access, Slack and Teams notifications, Email Audit and inbox placement. Start in the dashboard and automate the repeated checks when your team needs them. For the evaluation criteria, see our Litmus vs Email on Acid comparison.

Questions before you switch?

How can my team evaluate MailSlurp before the next campaign?

Choose a finished campaign and the client targets your subscribers use. Send it from your ESP, review the screenshots and ask a teammate to flag one correction. Resend the corrected version and compare matching results. Add Email Audit for links and images, then test placement separately before approving the final send. Try the campaign approval walkthrough.

Can I keep my email platform?

Yes. Send a campaign test from your existing ESP to a MailSlurp render address. You can also start with HTML or an exported .eml file. Make corrections in your editor and send a fresh test for comparison.

Can my team review results without writing code?

Yes. Use the dashboard to choose clients, inspect screenshots, compare revisions and add comments. Share the result and use Slack or Microsoft Teams notifications. The API supports repeat checks when your team wants automation.

See the email before your audience does.

Start with one campaign and review it on the clients your customers use.

Start previewing for free