Preview your HTML email in desktop, mobile, and dark mode.
Paste your email’s HTML or drop a .eml file and see it rendered instantly — flip between desktop and mobile widths, apply any of 20 client lenses (Gmail, Outlook, Apple Mail, Yahoo, Samsung, Thunderbird — per browser and per OS), and catch Gmail clipping before you send.
100% free · no signup · your HTML never leaves your browser · Updated July 2026
Paste it, drop it, or load a sample
Three ways in, zero setup — and everything renders locally in a sandboxed frame, so nothing you paste is ever uploaded.
- 1
Paste or drop your email
Paste raw HTML from your ESP’s code view, or drop a .html or .eml file — inline cid: images in .eml exports are resolved automatically.
- 2
Flip device, client, and dark mode
Switch desktop and mobile widths, rotate to landscape, apply any of 20 client lenses, and simulate per-client dark mode.
- 3
Catch issues before you send
Size and Gmail clipping, links and UTMs, missing alt text, http:// images — flagged instantly, with a full scored report one click away.
Every client renders your email differently
Dark mode and rendering quirks are where designed emails fall apart. Both simulations are modelled on documented client behavior — and both explain every change they make.
Dark mode, simulated per client
Apple Mail honors the dark-mode styles you author. Gmail and Outlook force-invert your colors — and no client ever inverts your images, which is exactly how bright logos end up glowing on dark backgrounds. This tool models each client's behavior with a CIELAB luminance transform, so what you see here is the mismatch your subscribers would have seen.
- Apple Mail, Gmail, and Outlook dark-mode models
- Images stay untouched — like they do in real clients
- Authored prefers-color-scheme styles are respected in the Apple model
See what each client takes away
“Gmail” isn't one target: Gmail in Chrome, Gmail in Safari, and the Gmail Android app are three different rendering engines. Classic Outlook for Windows still uses Word's engine (no border-radius, no box-shadow, no flexbox, no media queries at all), while Outlook.com is a normal web app that rewrites your class names. Pick any of 20 combinations and the lens applies that engine's documented limits to your email, then tells you exactly what changed and why — not a mystery screenshot, an explanation.
- 20 client, browser, and OS combinations — each mapped to the engine that renders it (Blink, WebKit, Gecko, or Word)
- A plain-English note for every transform applied, and an honest “unverified” note where behaviour isn’t documented
- Side-by-side compare for light vs dark or any two setups
Will Gmail clip your email?
Gmail hides everything past 102KB of HTML behind a “View entire message” link — including your unsubscribe footer. This tool measures your email the moment you paste it.
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Claim your 15% codeYour products, your story, and the unsubscribe link all fall past the cut, hidden behind a link most people never tap.
One year of cozy. Thank you.
You have been with us a whole year, and for a four-person studio that means the world. Here is 15% off your next order, on us.
Claim your 15% codeThe scents you loved most
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Email preferences Unsubscribe
Under the limit, so every section arrives at once. The CTA, the products, and your unsubscribe link all stay visible.
Preview emails from Mailchimp, Klaviyo, HubSpot, or Braze
Every major ESP lets you copy the rendered HTML or export the email — paste or drop it here to check rendering outside the editor’s comfort zone.
From Mailchimp
Open the campaign, choose Preview, then use your browser’s "Save page as" on the preview — or copy the HTML from the code editor and paste it here.
From Klaviyo
In the template editor choose Preview & test, view the HTML source, and copy it in — or export the template and drop the file here.
From HubSpot
Open the email’s Actions menu, choose Export as HTML (or copy from the source view), then paste or drop the file here.
From Braze
Copy the HTML body from the message composer’s source view and paste it here to check rendering before you launch.
When a preview needs a sign-off
A preview tells you the email renders. It doesn't get your client's approval on the record. Proofel takes the same email, gives you one link to share, and lets clients comment, annotate, and formally approve — no reviewer accounts, full version history, and an audit trail for every sign-off.
- One review link per email or whole campaign folder
- Pixel-pinned comments and annotations from anyone
- Approvals logged with version, reviewer, and timestamp
HTML email preview, answered
- Is this HTML email preview tool really free?
- Yes. Paste HTML or drop a .eml file and preview it in desktop, mobile, and dark mode with no signup and no usage limits. The full pre-send report (scored checks, link audit, spam score) unlocks with a free Proofel account, which includes every feature free for 14 days.
- Does my email HTML get uploaded anywhere?
- No. The preview, device simulation, dark-mode simulation, and all checks run entirely in your browser — your HTML never leaves your machine. The one exception is the optional spam check, which sends your email to SpamAssassin only when you explicitly click "Run spam check".
- Which email clients does the dark-mode simulation model?
- Apple Mail, Gmail, and Outlook. Apple Mail honors dark-mode styles you author with prefers-color-scheme; Gmail and Outlook force-invert colors. The simulation inverts luminance in the CIELAB color space per client model and never inverts images — exactly the mismatch that catches real emails out.
- Why does Gmail clip emails, and at what size?
- Gmail clips any email whose HTML exceeds 102KB, hiding the rest behind a "View entire message" link — including your unsubscribe footer. This tool measures your HTML and warns as you approach the limit; the Proofel app can also compress an email to fit.
- Can I preview a .eml file exported from my ESP?
- Yes. Drop a .eml file (from Mailchimp, Klaviyo, HubSpot, Braze, Outlook, or any ESP’s export/download option) and it is parsed in your browser, inline cid: images included. That makes this tool a free online .eml viewer too.
- Why don’t some of my images load in the preview?
- Images served over plain http:// are blocked by this page’s security policy — and most real email clients block or proxy them the same way. Serve every image over https. The insights strip flags any http:// image it finds.
- How accurate is the client simulation?
- It is a rules engine over documented behavior, not a screenshot from a real device — so we publish no accuracy percentage. Each of the 20 lenses is mapped to the engine that actually renders that client (Blink, WebKit, Gecko, or Word) and applies only transforms traceable to a documented limitation, with a plain-English note for every change. Where a behavior genuinely isn’t documented — a resizable reading pane, per-account Gmail differences — the lens says so instead of guessing. Treat it as a fast first pass and test important sends on real devices.
- How do I share a preview with a client for approval?
- That is Proofel itself: upload the email, send one link, and clients comment, annotate, and approve in the browser with no account. Reviewers are unlimited and the trial includes every feature for 14 days.
Preview is step one. Approval is the job.
Share the same email for client review and sign-off — one link, no reviewer accounts, every version on the record.
14-day all-access trial · no credit card required · reviewers never need an account