iPhone and Android
Check narrow screens, responsive columns, image scaling and buttons your readers need to tap.
Your Mailgun Inspect alternative for campaign previews.
Catch the broken layout before your customers do. MailSlurp shows your delivered campaign on real email clients and devices, ready for your team to review. Keep the email platform you already use.
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
Constant ContactOpen Constant Contact device preview guide
GetResponseOpen GetResponse device preview guide
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 guideChoose MailSlurp for the whole campaign review
Check the clients your customers use, compare a corrected send and let your team know when the previews are ready.
Review results as they arrive
Start with completed client screenshots while the remaining targets finish. Compare Gmail with Outlook, then place your corrected campaign beside the previous run to see what changed. Save the client selection as a profile so the next campaign gets the same checks. Follow the side-by-side comparison workflow.
Get preview updates in Slack or Teams
Notify reviewers in Slack or Microsoft Teams when a render status changes. Open the linked result to check the available client previews, then share the corrected run with colleagues before launch. The email review guide helps your team agree who checks what before sending.
Buy previews around your campaign calendar
A launch week and a quiet month need different amounts of testing. Start free, then choose prepaid capacity or pay-as-you-go usage. Allow for the clients you test and the reruns after a fix when comparing plans and preview allowances. For a larger team's workload, talk to us about the right package.
Moving from Email on Acid or evaluating Inspect?
Make the decision with a campaign your team already knows.
Keep your ESP. Get more from the review.
Mailgun's migration guide describes the move from Email on Acid to Inspect for previews and pre-send QA. Use that moment to try MailSlurp's device coverage, light and dark modes, revision comparisons and flexible billing with your own campaign. Our HubSpot campaign example includes seven saved desktop results from an actual test send, so you can see what a review involves before starting.
Follow up on sender issues
If a placement test raises a concern, use domain health monitoring to investigate SPF, DKIM, DMARC, MX and blocklist findings. Keep appearance, content checks and sender health in the same MailSlurp workspace, with a clear result for each question.
Bring in automation when the team needs it
Campaign reviewers can start in the dashboard. Developers can use the device render API to create runs and retrieve results, then add email and SMS journey testing for verification codes, password resets and customer notifications.
Questions before your first preview?
What to know when choosing MailSlurp as your Mailgun Inspect alternative.
Is MailSlurp an alternative to Mailgun Inspect for email previews?
Yes. Send a test campaign to MailSlurp and preview the delivered email across supported desktop and mobile clients. Compare light and dark modes, review a revised campaign beside an earlier run, and share the results with your team. You can do it in the dashboard without writing code. Explore device previews.
How are Email on Acid and Mailgun Inspect related?
Mailgun provides a migration path from Email on Acid to Inspect for previews and pre-send checks. If you are reviewing your options during that move, try your next campaign in MailSlurp: keep your existing ESP, test the clients your audience uses, and review the results with your team. Compare MailSlurp for an Email on Acid switch.
Do I need to move my campaigns or change my email provider?
No. Keep creating and sending campaigns in HubSpot, Mailchimp, Klaviyo or your existing provider. Send a test to a MailSlurp render address to review the delivered message. You can also start with HTML or import an exported .eml email file. Follow the Mailchimp preview guide.
How should I compare email preview costs?
Count the campaigns, client targets and reruns you expect to review. MailSlurp offers prepaid capacity and pay-as-you-go usage, so you can match preview spending to your campaign schedule. Check the current plans for allowances and the options your team needs. See current preview plans.
Can reviewers use Slack or Microsoft Teams?
Yes. Configure render-status notifications for Slack or Microsoft Teams, then use the result link to open the previews. Add comments to a run or a particular client screenshot in MailSlurp, compare a corrected version and resolve the comments after review. Your team decides when the campaign is approved to send. Set up review notifications.
Does a good preview mean the campaign will reach the inbox?
Appearance and placement need separate checks. Pair MailSlurp previews with an inbox placement test sent from your own email provider to the supplied test addresses. Review the inbox, promotions and spam results for those mailboxes, and use domain health monitoring to investigate sender configuration. A test result is evidence for that send, not a guarantee for every recipient. Check inbox placement.
Send your next campaign with a clearer view.
Start free with one test email. See it on the clients your customers use, fix the surprises and bring your team into the review.