Changelog

We've expanded the Email Campaigns API with two new endpoints, so you can list your campaigns and pull performance data programmatically instead of checking the dashboard.

Endpoints:

• List email campaigns – GET /api/email_campaigns returns a paginated list of your account's campaigns, newest first. Supports search to filter by campaign name, plus token/per_page for pagination (up to 100 per page).

• Get campaign statistics – GET /api/email_campaigns/{email_campaign_id}/stats returns aggregated performance metrics for a single campaign: counts and rates for deliveries, opens, clicks, bounces, spam complaints, and unsubscriptions. By default, it covers the full period since the campaign was last started — narrow it with the optional start_date and end_date query parameters.

A few things worth knowing:

• Stats are aggregated asynchronously, so numbers for a just-sent campaign may lag slightly behind real-time.

• Both endpoints are rate-limited to 150 requests per 10 seconds per API token.

For full request/response details, see the Email Campaigns and Campaign Stats API docs.

Mailtrap can now render captured HTML emails across a catalog of real email clients and devices, so you can see exactly how your HTML will look before it ever reaches a real inbox.

How it works: Capture an email in Sandbox, then open it in Device Previews and select the clients you want to test against. Mailtrap then generates one screenshot per selected configuration (Gmail, Outlook, Apple Mail, and a mix of mobile, desktop, and web setups).

What you can do with Device Previews

• See how each client renders your email – Get a screenshot per selected configuration, so you're comparing the actual rendered output, not guessing from a single preview.

• Check light and dark modes – Compare available light- and dark-mode variants side by side to catch unexpected changes to colors, backgrounds, logos, icons, and CTAs.

• Catch client-specific layout issues – Check stacking, spacing, font, image, button, background, and text-wrapping problems before sending the email to recipients.

• Focus each test on relevant clients – Choose from 100+ configurations and only test the ones relevant to your audience and your email.

• Test Templates, Campaigns, and Automation emails – Use Send Test to capture any Template, Campaign, or Automation email in Sandbox, then open it directly in Device Previews.

For more details, please check out our official Knowledge Base article.

Mailtrap now offers an official Terraform/OpenTofu provider and a Go SDK, so teams can manage Mailtrap setup as Infrastructure-as-Code and integrate in Go.

What's new:

• Official Go SDK (mailtrap-go) – Official Go library for Email API/SMTP, Email Marketing, and Email Sandbox. Go developers get the same “official SDK” experience as other languages, not only raw SMTP/REST samples.

• Official Terraform / OpenTofu provider – Official way to create/update/delete Mailtrap configuration resources from Terraform or OpenTofu. OpenTofu compatibility supports open-source and enterprise IaC stacks.

All in all, DevOps and platform teams can version, review, and repeat Mailtrap setup the same way they manage cloud infra.

It is quite common for one domain to send emails on behalf of several different companies or brands. For example, a freelancer or agency may manage email communication for multiple clients, an umbrella brand may send messages for its individual products or sub-brands, and a white-label platform may send emails on behalf of its customer accounts. These are legitimate business models, but without additional ownership verification, they can resemble phishing or brand impersonation.

To help with this, Mailtrap now offers a way to verify ownership of additional domains or brands referenced in your email content. 

How it works:

• Request verification through support – Contact the support team to request verification for an additional domain or brand (referred to as a company domain).

• Support adds the domain via the internal admin panel – Multiple company domains can be added to a single account.

• Mailtrap generates a unique verification token – You add it as a dedicated DNS TXT record (safe and purpose-specific, with no impact on your existing email setup).

• Automatic verification – Mailtrap checks the record automatically and marks the domain verified once it finds an exact match.

This process does not require SPF or DKIM changes, does not affect the customer’s email infrastructure, and does not allow the verified domain to send emails. It simply provides a reliable, auditable proof of ownership.

Important: The added domains do NOT count against the sending domains limit. Thus, even free plan accounts can request to add multiple company domains.

This feature helps Support distinguish legitimate multi-brand customers from potential phishing attempts, make more consistent decisions, and reduce unnecessary suspensions.

You can now set an expiration date when creating an API token, giving your team more control over how long credentials stay valid.

How it works: Set a token to expire in 1, 7, 30, 90, 180, or 365 days, pick a custom date, or configure it never to expire at all. We'll then send you both email and in-app notifications before your token expires. And once it does, it will no longer be able to authenticate API requests, but it will remain in your token list for up to 90 days along with its expiration date so you can see what happened and reissue it if needed.

This is another step toward making Mailtrap safer by default. It gives your team control over credential lifecycles and encourages stronger security practices, without adding unnecessary complexity to how tokens are managed.

Note: Existing tokens are unaffected. Any API token created before this update continues to work exactly as it did before, with no expiration. 

For more information, please consult our official Knowledge Base article.

From now on, you can ask our support team to restrict your email sending to approved recipient domains only. It’s ideal if you use Mailtrap for internal communication, ensuring emails are sent only to employees and never to external recipients.

What it means: In case your credentials get stolen, attackers cannot use them to send spam outside the allowlist. This protects your sender reputation and controls unwanted volume and costs.

You can request up to 20 allowlisted recipient domains per account.

Mailtrap has introduced Automated Domain Reputation Monitoring, giving you a centralized view of your domain health so you can identify deliverability and security issues before they impact your email performance. Instead of checking multiple tools, you can monitor key reputation signals, detect potential problems early, and take action from a single dashboard.

What you can monitor

• Sending performance - Track delivery rates, opens, clicks, bounces, spam complaints, and unsubscribe metrics.

• Bounce categories - Identify the types of delivery failures affecting your emails and monitor trends over time.

• Google Postmaster data - Monitor Gmail-specific reputation metrics, spam rates, and deliverability trends.

• Domain setup - Verify your domain configuration, including DNS records, authentication, dedicated IPs, and tracking settings.

• Security & abuse - Detect abnormal sending behavior, abuse attempts, phishing, malware, and other security risks.

• Blocklist status - Check whether your domains appear on known email blocklists that may affect deliverability.

Stay informed automatically

Configure automated email notifications to receive:

• Critical alerts - Immediate email notifications when high-priority issues are detected.

• Weekly summaries - Regular email reports highlighting your overall domain health, warnings, and positive trends.

Mailtrap Local is now available - a free, open-source email sandbox you run on your own machine. It catches every email your app sends during local development so nothing reaches real recipients, and gives you a web interface to inspect each message's HTML, text, headers, raw source, and attachments. When you're ready to collaborate or check real delivery, you can promote captured emails to Mailtrap Email Sandbox or relay them through an external SMTP provider.

What you can do with Mailtrap Local

• Capture emails locally - Intercept every email your application sends during local development.

• Inspect email content - Review HTML and plain-text versions, headers, raw source, and attachments in a built-in web interface.

• Send to Cloud - Promote any captured email to Mailtrap Email Sandbox so teammates can review it without shell access.

• Auto Relay - Forward captured emails through Mailtrap SMTP or an external SMTP provider, such as SendGrid, Mailgun, Amazon SES, or Postmark, to verify delivery in a real inbox.

For more information and installation instructions, visit the Mailtrap Local GitHub repository.