Emailens vs MailHog

Emailens previews HTML email rendering across 21 email clients and checks compatibility across 298 CSS and HTML features. It scores compatibility from 0 to 100 per client and provides rendered screenshots and simulated dark mode variants. Inputs include HTML, React Email JSX, MJML, and Maizzle. Developers can use a web app, REST API, MCP server, GitHub Action, or standalone @emailens/engine package. Campaign HTML can be imported from a view-in-browser link; Mailchimp URL import is marked verified, while other listed platforms require pasted HTML. Emailens discusses merge tags for Mailchimp, Klaviyo, HubSpot, Braze, and Salesforce Marketing Cloud. The free plan costs nothing and includes 30 simulated previews per day, all 21 clients, one monitored domain, seven-day audit history, and three AI Fixes. Paid plans are Dev at $9 a month, Pro at $19 a month, and Team at $49 a month. Emailens says unsaved previews are processed in memory and authenticated previews and screenshots are purged after 30 days.

MailHog is a free email testing tool for developers. Applications send mail to it over SMTP, after which users can inspect messages in a web interface or retrieve them through a JSON API. The interface displays plain text, HTML or source, supports encoded headers and updates in real time. The API can list, retrieve and delete messages, and download complete messages or individual MIME parts. Messages may also be released to real SMTP servers. MailHog supports ESMTP RFC5321, SMTP AUTH and PIPELINING, and includes a Chaos Monkey feature for failure testing. Storage defaults to memory, with MongoDB and Maildir also available. It can run from the command line, as a daemon, in Docker or on AWS Elastic Beanstalk. Its default SMTP and HTTP ports are 1025 and 8025. In-memory storage limits Elastic Beanstalk deployments to one instance; load-balanced deployments require MongoDB-backed storage. MailHog is released under the MIT license.