Emailens

Emailens previews how HTML email content renders across 21 email clients and checks compatibility across 298 CSS and HTML features. It assigns a compatibility score from 0 to 100 for each 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 engine package. Emailens can import campaign HTML from a view-in-browser link; Mailchimp URL import is marked verified, while other listed platforms require pasted HTML. It also discusses merge tags for Mailchimp, Klaviyo, HubSpot, Braze and Salesforce Marketing Cloud. The Free plan includes 30 simulated previews per day across all 21 clients and seven-day audit history. Paid plans start at $9/mo: Dev is listed 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. It states that connections use TLS 1.3 and storage uses AES-256 encryption at rest.

Emailens combines cross-client rendering previews with compatibility checks and several developer integrations. The Free plan is limited to 30 daily previews, while paid plans begin at $9/mo.

Emailens suits developers and email creators who need to check rendering across multiple clients before sending HTML email. The free plan is described as suited to hobbyists and individual developers, while Dev is aimed at freelance developers, indie hackers and creators.

Emailens is a rendering and compatibility checker for HTML email, aimed chiefly at developers building or reviewing campaigns. Its client-by-client scores and developer integrations make it a practical choice for implementation checks, though the lower tiers’ preview quotas limit how often teams can use it.

Overview

Emailens checks how email may appear across 21 clients and scores compatibility from 0 to 100 for each, based on 298 CSS and HTML features. Pairing screenshots with compatibility analysis gives developers more to work with than visual review alone: the score can help focus attention on implementation risks across clients.

It accepts HTML, React Email JSX, MJML, and Maizzle, and generates simulated dark-mode variants. Those formats make it useful across several email-building workflows, but the previews are simulated; they should not be mistaken for proof of rendering in a live inbox. Spam, accessibility, link, and inbox checks broaden the review beyond appearance.

Key features

• Rendering and compatibility: Screenshots show likely presentation while per-client scores offer a separate compatibility signal. This is useful when a developer needs to investigate more than whether a message looks right in one view.
• Workflow integrations: The web app, REST API, MCP server, GitHub Action, and standalone @emailens/engine package offer manual and developer-oriented ways to run checks. CI/CD and GitHub Action are included on Pro, making that tier the clearer fit for teams wanting checks in a build workflow.
• Campaign imports: Emailens can import campaign HTML from a view-in-browser link. Mailchimp URL import is verified; for other supported ESPs—Klaviyo, HubSpot, Braze, and Salesforce Marketing Cloud—the instructions are to paste HTML. Merge-tag support is discussed for those platforms, but the distinction matters if a workflow depends on importing a campaign directly.
• Security and privacy: Unsaved previews are processed in memory, while authenticated previews and screenshots are purged after 30 days. Connections use TLS 1.3 and stored data is encrypted with AES-256 at rest. Email HTML, templates, and prompts processed through AI Fix and AI Builder are not used to train foundation models. Users can sign in with email and password, Google, or GitHub, and can request data rights through [email protected].

Pricing

Emailens has a free plan and three paid tiers, with no free trial. The free plan is a useful starting point for hobbyists and individual developers, but its 30 simulated previews per day and seven-day audit history are restrictive for sustained campaign work.

• Free — $0 forever: 30 simulated previews per day, all 21 clients, one monitored domain, seven-day audit history, and three AI Fixes. It suits occasional checks, but the daily quota and short history leave little room for frequent review or longer-term comparison.
• Dev — $9/mo or $90 a year: 100 simulated previews per day, one API key, three monitored domains, 30-day audit history, 10 AI Fixes per month, and three Builder runs per month. It is built for freelance developers, indie hackers, and creators; the higher quota and API key support regular work, though the single key and limited Builder runs constrain broader team or automation use.
• Pro — $19/mo or $180 a year: Unlimited previews, 10 API keys, 10 monitored domains, one-year audit history, CI/CD and GitHub Action, and 30 Builder runs per day. This is the stronger fit for heavier workloads and integrated checks, at a substantial step up from Dev.
• Team — $49 / mo or $490 / yr: 100 AI Builder runs per day, centralized team billing, and a 365-day audit archive. It addresses shared billing and longer audit retention, but its stated inclusions focus on team administration and Builder capacity rather than preview or API quotas.

Paid plans renew according to their monthly or annual billing term; no free trial is offered. The annual prices are lower than paying the corresponding monthly rate for a full year: Dev is $90 a year rather than $108, Pro is $180 rather than $228, and Team is $490 rather than $588.

Platforms

Emailens is available as a web app, API, and extension. Its REST API and standalone engine add developer-facing access alongside the web workflow. The supported client set covers 21 email clients, with both device types represented.

Who it's for

Emailens is best suited to developers who need to check email rendering and compatibility across clients, especially those already working in HTML, React Email JSX, MJML, or Maizzle. The Free plan can serve occasional individual checks; Dev is a better match for ongoing solo development. Pro makes more sense when preview volume is high or checks need to run in CI/CD. Teams chiefly seeking centralized billing and a long audit archive may value Team, while occasional users who need real-world rendering rather than simulated previews should consider whether Emailens fits their testing needs.

Pros and cons

• Pro: Compatibility scores accompany screenshots across 21 clients, helping developers examine both likely appearance and feature support.
• Pro: Support for four input formats and several developer integrations can accommodate different authoring and review workflows.
• Pro: The Free plan includes all 21 clients and three AI Fixes, so a new user can assess core checks without a paid subscription.
• Con: Free is capped at 30 simulated previews per day and seven days of audit history, which can be limiting for frequent checks or longer review cycles.
• Con: Dev limits users to one API key and three Builder runs per month; automated or team workflows may need the more expensive Pro tier.
• Con: Direct campaign URL import is verified for Mailchimp; other supported ESP workflows require pasting HTML.

Alternatives

For a broader selection of tools in the category, browse Email Testing Software.

• EmailQA is worth considering when its free allowance of 25 real-device renders per month, three projects, and two team members better fits a small team’s needs; its Pro plan is $20.00 per month.
• Mailpit is a free alternative for users who want a self-hosted option, with a single static binary or Docker images and retention of the most recent 500 emails.
• Postdrop may suit users looking for a web-based plan with templates, exports, daily test emails, and dark-mode preview; its free plan has no live client preview credits.
• MailSlurp may fit workflows centered on receiving and sandboxing email, with 500 emails received and 1,000 sandbox sends per month on its free plan, though that plan includes only one device render per month.
• Mailtrap Email Sandbox is another free API and web option, with 50 test emails per month, one user, and one sandbox on its Free plan.
• GlockApps is an alternative to consider for users whose needs align with its free spam-test credits and DMARC monitoring allowances.
• Mailinator is another freemium option for users comparing email-testing tools.
• Twilio Segment is a freemium web, iOS, and Android option to consider as a separate alternative.

Verdict

Choose Emailens if you are a developer who needs simulated email previews plus per-client compatibility analysis, with a path from occasional web checks to API and CI/CD workflows. Its clearest advantage is combining screenshots with compatibility scores across 21 clients; look elsewhere if you need verified live-inbox rendering or if the free and Dev quotas cannot accommodate your review volume.