Email preview tools compared: 6 that render on real devices

An email preview tool has one job: show you what your message looks like in Outlook on Windows, Gmail on a Pixel, or Apple Mail on an iPhone in dark mode. Most tools with "preview" in the name don't do it. They resize your HTML in a phone-shaped frame or check your CSS against a support table, and neither shows you what Outlook actually did to your layout.

The six tools below render on real clients and return screenshots. Prices are from each vendor's pricing page in September 2026, except Litmus, which no longer publishes any. Vendors name the unit differently (Litmus "previews," Mailchimp "tokens," Parcel "inbox previews," Unspam "device previews"), but wherever it's documented, one unit is one screenshot from one client. A run against 8 clients costs 8. Where a vendor doesn't publish its unit, the table says so.

Quick picks:

• Courier for any HTML email: real-device screenshots from inside the editor or the API, on the exact message you send, from $20 a month.
• Litmus if you need the longest client list and have budget for a sales-negotiated contract. There's no self-serve plan anymore.
• SendForensics if you want unlimited previews bundled with deliverability monitoring for $49 a month.
• Parcel if you hand-code email and want previews next to the code.

Courier Cross-Device Email Preview

Cross-Device Email Preview is Courier's real-device email preview, built into the Design Studio editor and available through the API. Click the device icon, pick your clients, and screenshots come back from the real apps: Outlook itself on Windows, Apple Mail on an iPhone, Gmail on a Pixel.

Coverage: 96 clients across 21 apps, most in light and dark mode. Apple Mail on macOS and iOS 16 through 26, every Outlook desktop version from 2016 through 2024 plus Microsoft 365, Gmail on iPhone and Pixel 6 through 10, and webmail including Gmail.com, Outlook.com, Yahoo, AOL, GMX, and Web.de.

Pricing: a monthly add-on, enabled in Settings under Billing. One preview is one client screenshot.

Ease of use: no export step. The draft you're editing is what gets rendered, variables filled, unpublished changes included. Runs take 10 to 60 seconds, screenshots stream in as each client finishes, and every one shows the full inbox view, so you check the subject line and sender name in the same pass. Target sets are shared across your workspace, and Courier keeps every run for a year with the template version that was live.

API: yes, both directions. Send HTML or point at a template, trigger a run against a target set from a script or CI step, and pull the screenshots back when they're done.

Any HTML works. A Courier template is HTML. Build it in Design Studio, paste it in, or send it through the API from the platform you already use. The preview runs the same way.

Litmus

Litmus is the incumbent, with the longest client list ("100+ popular email clients," dark mode included) and a builder, checklist, analytics, and personalization bundled around it. Since 2025 it's sold as part of Validity Engage.

Pricing: there isn't a price. There's a sales call. The pricing page is now a Validity contact form, with no self-serve plan and no rate card, so you pay whatever the rep thinks you'll pay.

The last published number was Core at $500 per month for 5 users and 2,000 previews (Capterra, September 2026), already the result of an August 2025 reprice that killed the $79 and $199 plans. Real contracts run higher: Vendr's data (February 2026) puts the median buyer at $17,500 a year, with deals from $8,000 to over $30,000.

Each screenshot is one preview. Litmus's default run is 35 clients, so one test plus one rerun burns 70. At $500 for 2,000 that's $0.25 per preview if you use every one, and unused previews don't roll over.

Ease of use: send from your ESP to a Litmus test address, paste HTML into the Litmus builder, or use the Chrome extension. Then pick clients, wait, fix the template wherever you actually build it, and repeat. Litmus renders the HTML you gave it, not what your platform sends after variables and tracking are injected, unless you're on Salesforce Marketing Cloud, Marketo, or Responsys.

API: exists, but "access to Litmus APIs is evaluated on a case-by-case basis." Don't plan on it.

Parcel

Parcel is a code editor for email with real-inbox previews attached: 89 inboxes (26 mobile, 45 web, 16 desktop, 2 tablet), dark mode selectable per preview.

Pricing: previews are an add-on to a paid seat. Pro is $29 per user per month, Business $56. The Inbox Previews add-on "starts at $49/month and includes 500 previews," with overage at an unpublished rate, and "each load and refresh counts towards your plan's usage." On your own, that's $78 a month, about $0.16 per preview at full use. The free tier has no inbox previews.

Ease of use: good if you live in the editor. Your HTML or MJML is already there, so you click Inbox Previews, filter, pick dark mode, and get a grid. Two gaps: previews show only the body, not the subject line or sender, and there's no published run time.

API: none for previews.

Mailosaur

Mailosaur is a test-inbox product for QA teams with real-device previews added. Its wording is the clearest in the category: previews are "fully native," showing "how emails actually render in the inboxes your customers use," in light and dark mode.

Pricing: Core from $50 a month billed annually (5 seats), plus email previews "from $25 per month." What one preview is and how many $25 buys aren't published, so there's no honest per-preview figure. Minimum realistic spend is $75 a month. No client count is published; a third-party test in 2023 counted 85.

Ease of use: send-then-preview. Your app sends to a Mailosaur address, and you generate previews from the received message. Good for fidelity, since personalization is already resolved. Slow if you're iterating on a design, since every change means another send.

API: the platform is API-first, but automating previews is Enterprise only.

SendForensics

SendForensics is a deliverability platform (inbox placement, DMARC) with client previews included: "60+ clients to choose from, with light and dark modes where supported."

One caveat on method. An earlier version of its previews page said it "only tests using live devices," sending each email "to an actual device" and screenshotting it. That page has been archived, and the current one doesn't say how previews are captured. Confirm before you rely on it.

Pricing: Brand $49 a month (2 users), Company $79 (5), Agency $199 (10), Enterprise from $349 (20), about 20% less annually. Every plan includes unlimited client previews, the cheapest unlimited option here if you'll also use the deliverability tooling.

Ease of use: thinly documented. ESP plugins suggest a send-a-test flow, but the vendor doesn't publish how HTML gets in, run time, or whether previews show the inbox view. It's a deliverability suite that includes previews, not a preview-first tool.

API: none found.

Unspam.email

Unspam is a small spam-and-preview tester with the plainest real-device statement in the category: "your email opened in an actual copy of the client and device, not a mockup or a browser simulation." Coverage is 50+ clients, each in light and dark mode.

Pricing: Free with 3 device previews a month, Basic $9 for 10, Business $19 for 50, Agency $29 for 250. No overage; quotas don't roll over. The headline prices look cheap, but the previews aren't: Basic is $0.90 per screenshot and Business $0.38, the highest rates here. A full run across its lineup is "more than 100 renders," which no tier below Agency ($0.12) can afford. Its separate "real email previews" quota is a different, undefined feature.

Ease of use: paste HTML or send a real email, results "in about a minute." No inbox view documented.

API: none found.

Previews built into your email platform

If you send from a marketing platform, it may have a real-device preview built in. Nearly all are white-labeled Litmus or Email on Acid, sold as a small token allowance. From vendor help centers, September 2026:

Most allowances are tiny: 25 previews a month on Mailchimp is three runs against an 8-client set. And among notification platforms, Courier is the only one with real-device previews on a self-serve plan. Knock gates them to Enterprise; Customer.io and OneSignal simulate.

Side-by-side comparison

Why Courier comes out ahead

Courier wins on price and on ease of use, for any HTML email. Litmus has a longer client list and SendForensics has an unlimited plan; nothing else puts real-device screenshots, the exact rendered send, and an open API in one place at a self-serve price.

On price: $100 for 1,000 previews is a fifth of Litmus's last published price ($500 for 2,000), before the sales call raises it, and cheaper per preview at every tier. Against ESP-embedded previews, $20 buys four times Mailchimp's monthly allowance, with no Enterprise contract required.

On ease of use: every other tool needs the email brought to it. Paste, upload, send to a test address, or install an extension, then carry the fix back to where you build. Courier renders the draft you have open, variables filled, in one click, and the screenshot is the message your users will receive. Only Mailosaur matches that fidelity, and only by making you send first. Add the inbox view, shared target sets, a year of history, and an API that runs previews and returns the screenshots, and the choice is made.

If a renewal quote has you searching for a Litmus alternative, the math is $20 to $100 a month with no round trip against $500 and a negotiation.

Evaluation criteria

• Real capture or simulation. Only a screenshot from the actual client shows what Outlook did to your table widths. Every tool here states it on a current page except SendForensics.
• Price at your real volume. Clients tested, times reruns, against included previews. Unlimited plans win at high volume; per-preview plans win for a focused 8-client set a few times a week.
• Distance from your editor. Every step between "I changed it" and "I see it" gets skipped on a busy day. Tools inside the editor get used.
• Fidelity to the real send. The HTML you pasted, or the message your platform sends with variables and tracking in place? Only Courier and Mailosaur render the real thing by default.
• Inbox view. Subject line and sender name are part of the render. Only Courier and Litmus document showing them.
• API access. For previews in CI or on every publish. Most tools here don't have one, or gate it.
• Coverage that matches your recipients. 100+ sounds better than 96. The question is whether your top eight clients are covered in both color modes.

Frequently asked questions

What is a real-device email preview?

A screenshot of your email opened in an actual email client on real hardware or a real OS install, such as Outlook 2019 on Windows 10 or Apple Mail on an iPhone 17. It differs from a browser simulation, which resizes your HTML in a frame, and from CSS analysis, which checks your code against a support table without rendering it.

Is there a cheaper alternative to Litmus for email previews?

Yes. Courier's Cross-Device Email Preview starts at $20 a month for 100 real-client screenshots and works with any HTML email, and SendForensics includes unlimited previews from $49. Litmus has no self-serve plan; its last listed price was $500 a month (Capterra, September 2026), and real contracts run far higher.

How much does Litmus cost in 2026?

Litmus no longer publishes prices or sells a self-serve plan; every deal is a sales negotiation. The last listed figure was Core at $500 per month for 5 users and 2,000 previews (Capterra, September 2026), after Litmus retired its $79 to $199 plans in August 2025. Vendr's contract data puts the median buyer at $17,500 a year.

Do Mailchimp, Klaviyo, or HubSpot have real email previews?

Yes, mostly white-labeled. Mailchimp's Inbox Preview is Litmus-powered with 25 tokens a month. Klaviyo's inbox testing is Mailgun-powered with 100 tests per user per month. HubSpot's is Litmus-powered and limited to Marketing Hub Professional (500 tests per 30 days) and Enterprise (1,500).

Can I run email previews from an API?

Courier exposes previews through its API, both to trigger runs and to retrieve screenshots. Litmus has an Instant API but grants access case by case. Mailosaur automates previews on Enterprise plans only. Parcel, SendForensics, and Unspam don't publish a preview API.

What counts as one preview?

One screenshot from one client, wherever the vendor documents it: Courier, Litmus, Unspam, Mailchimp, Klaviyo, HubSpot, and Constant Contact all count that way. A run against 8 clients uses 8 previews. Parcel also counts each refresh. Mailosaur and SendGrid don't publish their unit.

Related resources:

• Cross-Device Email Preview docs
• Introducing Cross-Device Email Preview
• Dark mode email design