iPhone and Android
Check narrow screens, responsive columns, image scaling and buttons your readers need to tap.
Litmus or Email on Acid? Meet MailSlurp.
Catch broken layouts on real email clients, test light and dark mode, and check inbox placement. MailSlurp works with the ESP you already use, with prepaid or pay-as-you-go previews.
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
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 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.
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.
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
Find broken links and images
Email Audit checks the delivered message for broken links, missing images, unresolved placeholders and other content issues.
Test inbox placement
See inbox, Promotions, spam and not-received results from the provider mailboxes in your placement test.
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
Prepaid or pay as you go
Choose capacity around the number of campaigns, client targets and corrections your team expects to review.
API access for repeat checks
Create render runs, retrieve results and connect email previews to your application tests or CI workflow.
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 test email workflow for your sending platform.
BrazeOpen Braze device preview guide
BrevoOpen Brevo device preview guide
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HubSpotOpen HubSpot device preview guide
KitOpen Kit device preview guide
KlaviyoOpen Klaviyo device preview guide
MailchimpOpen Mailchimp device preview guide
MailerLiteOpen MailerLite device preview guide
MailjetOpen Mailjet device preview guide
OmnisendOpen Omnisend device preview guideResendOpen Resend device preview guide
SalesforceOpen Salesforce device preview guide
SendGridOpen SendGrid device preview guideWooCommerceOpen WooCommerce device preview guideCompare the workflow with your own campaign.
Review a campaign your team knows
Use a finished email with the typography, images and tracking links you normally send. Choose matching client targets and display modes. Check that a mobile button is easy to tap, a two-column layout stacks correctly and the logo stays visible in dark mode. Make a correction, resend from your ESP and compare the same client. For a specific switch, see our Litmus alternative and Email on Acid alternative pages.
Include the checks after the preview
MailSlurp brings that review together with flexible preview capacity, API access, Slack and Teams notifications, Email Audit and inbox placement testing. Start with the dashboard and add automation when the team needs the same checks for every release. Compare current preview plans against your campaigns, client targets and reruns, including busy launch weeks.
Questions before you switch?
What should a Litmus vs Email on Acid comparison include?
Start with the clients your audience uses, including Outlook, Gmail, iPhone and Android, and check the available light and dark modes. Test the same finished campaign, correct a layout issue and compare matching client results. MailSlurp adds prepaid or pay-as-you-go capacity, API access, content audits and separate inbox placement checks. Count the targets and reruns you need when comparing costs. See the review workflow in practice.
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.