Mailgun Inspect lets you test your email before you send it. You can preview it across 100+ email clients and devices, catch broken links, missing images and accessibility issues, check code support, and see how spam filters handle your content. You can also fix your HTML, re-test and comment with your team, all in one place.
This guide covers setting up your account, adding your team, running your first test, reviewing results, and working with your team on fixes.
Before you begin
| Requirement | Notes |
|---|---|
| A Mailgun account with Inspect access |
New to Mailgun? Start a free trial and get 20% off for 3 months. Already have a Mailgun account? Add an Inspect free trial to your account. |
| Your email content | Your HTML, a URL that hosts your email, or access to your ESP so you can send a test email. |
Plans and features
| Basic | Premium | Contract | |
|---|---|---|---|
| Price | $99/month | $199/month | Custom |
| Previews included | 1,000/month | 2,000/month | Custom |
| Overage per preview | $0.15 | $0.15 | Custom |
| Email previews across 100+ clients and devices | Yes | Yes | Yes |
| Comments on previews | Yes | Yes | Yes |
| Link and image validation | No | Yes | Yes |
| Accessibility testing | No | Yes | Yes |
| HTML code analysis | No | Yes | Yes |
| Spam testing | No | Yes | Yes |
| HTML editor and version history | No | Yes | Yes |
| Access to integrations | Yes | Yes | Yes |
All plans come with unlimited user seats.
Subscription plans go up to 2,000 previews per month. If you need more, contact sales about a contract.
1. Sign In
- Go to Mailgun and sign in.
- If you land on the general Mailgun dashboard, click Inspect in the sidebar. All of Inspect is on that one page.
2. Add Your Team
Invite anyone involved in email QA or approvals early, so they can review tests and leave comments with you.
- Click on your name at the top right of the page.
- Scroll down to Inspect Settings and choose User Accounts.
- Do not go to the User Management page under the general Account Settings - Inspect users need to be added separately from regular Mailgun users.
- Click New User.
- Enter their email address and assign a role - this role is for all of Mailgun (details).
- Send the invite. Your teammate will get an email inviting them to join your account.
Set Mailgun Inspect User Profiles: A user's role controls their access across all of Mailgun. User profiles set permissions for Inspect only. To create or edit profiles, click Manage user profiles on the Inspect User Accounts page.
NOTE: All other account management exists across all of Mailgun. That information can be found here.
3. Understand usage
Inspect usage is based on the number of previews you run. One preview = one client rendering. If you test against 100 clients, that uses 100 previews, not one.
- Your current usage and allotment are shown in the top right of the main Inspect page. You can also find them by clicking your name and selecting Plan & Billing.
- Usage on subscription plans resets every month. Usage on contract plans is tracked every year.
- QA checks, code analysis and spam testing come with every test and don't have separate limits.
- Retesting, or saving a new version in the HTML editor, uses previews again.
Tip: Choose the clients your audience actually uses. A focused set of 30 to 50 clients catches the most important rendering problems and makes your allotment last 2 to 3 times longer.
4. Run your first test
Click New Test and choose how to add your email:
| Method | Description |
|---|---|
| Send from your ESP |
Best for long term workflow. Submit your test from your ESP. We generate a custom email address connected to your account that you can send to, and the test will show up in your account. Note: You can select a folder to route your email to or a pre-set list of which previews you want (preview profile) when you create this email address, which will add tags to the email address. Once you create this email address, it will not change. |
| Paste your HTML directly | This is the simplest - just copy in subject line and HTML. |
| Upload from a URL | This is the simplest option if you host your HTML on a webpage. |
| Upload via zipfile | Upload a zipfile with your HTML and images. |
| Upload Mailgun template | If you use Mailgun templates, you can directly upload them. |
Best practice: If you're testing a production email, use the exact HTML you plan to send.
Enter details
Enter a Test Name you'll recognize later. If you use folders, you can also choose a folder for the test. Folders are optional, but they help if you have many teams or campaign types.
Choose previews
Select which email clients to include by using a preview profile. A preview profile is a pre-set list of which previews you want to include. You can:
- Start with all previews. This is the most thorough option but uses the most previews.
- Choose an existing preview profile, if someone on your account has created one.
- Click Create new below the dropdown to build your own preview profile.
Note: If you set a profile as the default, it becomes the default for everyone on your account.
Add your content
- Send from your ESP: Copy the email address shown, then send your email to it from your ESP. Your email will appear in about 5 minutes.
- Paste your HTML directly: Enter a subject line and your HTML, then click Test email.
- Upload from a URL: Enter a subject line and the URL of your email, then click Test email.
- Upload from a zipfile: Upload the zipfile containing the HTML and elements you need, then click Test email.
- Upload Mailgun Template: Choose your template, enter in the test details, then click Test email.
5. Review your results
When your test is ready, click it to open the results. Results are organized into three tabs.
Previews
Previews show how your email renders across the clients and devices you chose, including dark mode versions. Look for layout shifts, broken formatting and missing elements.
Fix issues (Premium and Contract)
- QA runs automated checks for broken links, missing images and accessibility issues. Click an issue to see it highlighted on a rendering of your email and in the HTML.
- Code analysis flags HTML and CSS that key email clients don't support or only partly support. Use the filters to focus on specific inbox providers or issue types.
Spam check (Premium and Contract)
The Spam check tab shows how major mailbox providers and B2B spam filters handled your content. Inspect sends your email from one of its high-reputation IPs. That way the results reflect your content, not your sender reputation.
Export and share
- Click Export to download screenshots or a summary of the issues found on the Fix issues tab.
- Click the share icon to create a link to your results. Anyone with the link can view the results, so share it carefully. Comments aren't included on share links.
6. Comment on previews
Comments let your team discuss issues and approvals right on the email. They're available on every plan.
- Open a test and go to the Previews tab.
- Open the preview you want to comment on.
- Leave a comment on the whole preview, or click a spot on the preview to pin your comment there.
Things to know:
- Comments are only visible to users on your account. People viewing a share link won't see them.
- @mentions and comment notifications are coming soon.
7. Fix issues and retest with the code editor
On Premium and Contract plans, you can edit your HTML directly on the Fix issues tab. Click in the HTML editor, make your changes, then click Save. You can then choose one of these options:
- Update current version saves your changes without re-running previews or checks. It doesn't use previews, but it replaces the current HTML.
- Save as new version creates a new version (Version 2, Version 3, and so on) and automatically re-runs previews and checks. It uses previews.
To switch between or restore earlier versions, click the clock icon next to Save. You can also click Retest at the top of the page to test updated or new HTML.
For full details, see Edit and retest email HTML with the Inspect live editor.
Common workflow: Test → Review and comment → Fix → Save as new version → Export → Send
Other ways to use Inspect
| Tool | What it does | Get started |
|---|---|---|
| Chrome extension | Test emails right inside your ESP's editor, with results in a side panel. | Install from the Chrome Web Store · Setup guide |
| VS Code extension | Test emails from your code editor. Available on VS Code desktop. | Setup guide |
| Salesforce Marketing Cloud | Test emails from SFMC. | Setup guide |
| API | Everything in Inspect is available through the API. | API documentation |
Change your plan
To upgrade or downgrade a subscription plan, click your name in the top right and select Plan & Billing. If you need more than 2,000 previews per month, contact sales about a contract.
Troubleshooting
I can't access Fix issues or Spam check tabs.
These are available on Premium and Contract plans. On Basic, you'll see only Previews.
My teammate can't access Inspect.
Make sure you added them from Inspect Settings > User Accounts, not from User Management under Account Settings.
My ESP test hasn't shown up.
Tests can take about 5 minutes to appear. Check that you sent the email to the exact address shown when you created the test.
Someone I shared a link with can't see our comments.
Comments aren't included on share links. To see them, the person needs to be added as a user on your account.
My results say they may be outdated.
You (or someone else) updated the HTML without creating a new version. Click Retest to see latest to get fresh previews and checks.
I'm using previews faster than expected.
Every client you select uses one preview each time you test, retest or save a new version. Build a preview profile with only the clients your audience uses. Read this article to better understand how to manage usage.