HTML Email builder

HTML Email Builder

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What is HTML Email Builder

HTML Email Builder is a free browser workspace for editing HTML email, previewing it in client-style layouts, running local QA and compatibility checks, filling merge-tag payloads, and sending a test through your own Mailpit-compatible HTTPS endpoint.

Import .html or .eml, format or minify the source, inline CSS, and review light/dark and desktop/mobile form factors. Download saves email-template.html. Client previews are simulations in your browser — not native Gmail or Outlook rendering engines.

Send test never stores mail on Tools Viewer; it posts to the Base URL you configure (typically Mailpit behind an HTTPS tunnel such as ngrok).

How to use HTML Email Builder

  1. Step 1: Load your email HTML. Paste HTML, Import .html / .htm / .eml / .mime, or start from Templates.
  2. Step 2: Preview across clients and themes. Pick client-style profiles, add side-by-side devices, and switch light/dark plus desktop/mobile form factors.
  3. Step 3: Clean up and personalize. Use Format HTML, Inline CSS, or Minify. Open Payload to supply JSON for {{ variables }} so personalized regions fill in during preview.
  4. Step 4: Check, download, or send a test. Run Check email (HTML, source, text, headers, QA, HTML Check, Link Check). Download email-template.html, or Send test to your Mailpit HTTPS Base URL.

HTML Email Builder Features

  • HTML email editor with live client-style previews
  • Import .html, .htm, .eml, and .mime
  • Format HTML, Inline CSS, and Minify
  • Templates gallery and Payload JSON for merge tags
  • Send test via your Mailpit-compatible HTTPS Base URL
  • Check email: HTML, HTML Source, Text, Headers, QA Report, HTML Check, Link Check
  • Download as email-template.html
  • Light / dark preview and desktop / mobile form factors

Common use cases

  • Proof transactional emails: Review receipts, password resets, and onboarding mail before uploading HTML to an ESP.
  • Open a saved .eml: Import an .eml from support or QA and inspect the rendered body and checks.
  • Merge-tag dry runs: Apply a sample Payload so {{ variables }} show realistic values in preview.
  • QA before launch: Use Check email for QA findings, HTML Check (caniemail data), and link checks.
  • Mailpit send test: Send through your own Mailpit instance exposed with HTTPS (for example ngrok) without Tools Viewer hosting a mailbox.
  • Hand off clean HTML: Format, inline CSS, or minify, then Download email-template.html for your campaign tool.

Examples / supported formats

Inputs and outputs available in HTML Email Builder:

  • HTML email markup in the editor
  • Import: .html, .htm, .eml, .mime
  • Download: email-template.html
  • Payload JSON for {{ variable }} previews
  • Send test to your configured Mailpit-compatible endpoint

Authoring in MJML instead? Use MJML Email Builder. For screenshot or PDF captures of HTML, see HTML to PNG, HTML to JPG, or HTML to PDF. Setup help: Mailpit + ngrok guide.

FAQ

Is HTML Email Builder free?
Yes. Tools Viewer tools are free to use in the browser with no account required.
Do I need to create an account to use HTML Email Builder?
No. Open the tool and start working — signup is not required.
Is my email HTML stored on Tools Viewer servers?
Editing, preview, and checks run in your browser. Send test posts to the Base URL you set (for example Mailpit behind HTTPS). Tools Viewer does not host your mailbox. For MJML authoring, see MJML Email Builder.
Can I export the email as PDF, PNG, or JPG?
Download saves HTML. Check email can print a QA report from the browser print dialog. For image or PDF snapshots, use HTML to PDF, HTML to PNG, or HTML to JPG.
What should I put in the Send test Base URL?
Use an HTTPS URL for your Mailpit (or compatible) instance — typically an ngrok tunnel. See the Mailpit + ngrok setup guide for CORS and Docker details.
Are client previews exact Gmail or Outlook engines?
No. Previews are client-style simulations in your browser. Always send a real test through your ESP or Mailpit before a major send.
What is a good HTML email preview tool?
A strong workflow lets you edit HTML, check multiple layouts, run local QA, preview merge tags, and send a test to infrastructure you control — without forcing an account. That is the focus of HTML Email Builder on Tools Viewer.

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