HTML Email Checker for Error-Free & Responsive Emails

Q: How do I know if my email HTML is broken?

You can run your HTML through a validator to instantly detect missing tags, CSS errors, and layout issues that may break your email.

Q: How can I test emails before sending campaigns?

By running pre-send HTML checks, you can catch rendering issues, broken code, and formatting errors early before launching your email campaign.

Q: Is automated email testing really necessary?

Yes, automated email testing is important for ensuring consistent and error-free emails at scale, especially for growing campaigns where mistakes can increase.

Q: Who should use an HTML Email Checker?

An HTML Email Checker is useful for email marketers, developers, CRM teams, agencies, and SaaS companies that regularly send email campaigns.

Core Features

Powerful HTML Checker for Better Emails

All that you need is in one place. Time to validate your email code, detect rendering issues, and improve inbox compatibility strongly with our HTML checker.

truesend.io/html-checker

Live Analysis

email-template.html

1 <table role="presentation">

2 <tr><td style="padding:20px">

3 <h1 style="color:#2563eb">Welcome</h1>

4 <div style="display:flex">

5 <img src="hero.png" />

6 <a style="border-radius:8px">

7 </div>

8 </td></tr>

9 </table>

94%

Compatibility Score

Checked against 90+ clients

Gmail

100%

Apple Mail

100%

Outlook

78%

Yahoo

97%

Samsung

95%

flexbox not supported in Outlook

border-radius partial in Outlook

7 of 9 rules fully compatible

HTML Code Validation

You can easily find broken tags, coding errors, unsupported CSS, and layout issues before sending your emails with this feature.

Responsive Email Preview

Act smart and preview first how your emails will appear on desktop, mobile, and different screen sizes. No mistakes for later.

Compatibility Testing

At trueSend, you can easily check if your email is compatible with major inbox providers like Gmail, Outlook, and Yahoo Mail. It keeps every design consistent.

Auto-Fix Recommendations

Get quick suggestions to fix HTML issues, improve deliverability, and optimize email performance.

How It Works

Check Your Email HTML in 3 Simple Steps

Catch coding errors, test inbox compatibility, and launch flawless email campaigns in just three simple steps.

Paste or Upload Your Email HTML

Firstly, upload your email template or code to our HTML checker.

Scan for Errors & Compatibility Issues

The second step is to detect broken HTML, unsupported CSS, and rendering problems across major email clients.

Preview, Fix & Launch Your Campaign

Lastly, optimize your email layout, apply fixes, and send emails with better inbox compatibility.

API Integration

Automate Email HTML Checks with API

Plug HTML validation straight into your workflow and let every email template get checked for errors, layout issues, and inbox compatibility before it ever reaches your audience.

API Reference

// Node.js HTML Checker API
const axios = require('axios');

const response = await axios.post(
  'https://api.truesend.io/v1/html-check',
  {
    html: '<html>...your email...</html>',
    clients: ['gmail', 'outlook', 'apple_mail']
  },
  {
    headers: {
      'Authorization': 'Bearer ts_api_key'
    }
  }
);

console.log(response.data.score);
// → 94.5 (out of 100)
console.log(response.data.issues);
// → [{ client: "outlook", rule: "no-flexbox" }]

# Python HTML Checker API
import requests

response = requests.post(
    'https://api.truesend.io/v1/html-check',
    json={
        'html': '<html>...your email...</html>',
        'clients': ['gmail', 'outlook', 'apple_mail']
    },
    headers={
        'Authorization': 'Bearer ts_api_key'
    }
)

data = response.json()
print(data['score'])
# → 94.5 (out of 100)
print(data['issues'])
# → [{"client": "outlook", "rule": "no-flexbox"}]

// PHP HTML Checker API
$ch = curl_init(
    'https://api.truesend.io/v1/html-check'
);

curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer ts_api_key',
        'Content-Type: application/json'
    ],
    CURLOPT_POSTFIELDS => json_encode([
        'html' => '<html>...email...</html>',
        'clients' => ['gmail', 'outlook']
    ])
]);

$result = json_decode(
    curl_exec($ch), true
);
echo $result['score'];
// → 94.5

Related Tools

Complete HTML Checker Toolkit

A complete set of built-in tools that work together to validate, test, and
refine your email HTML before sending.

HTML Structure Scanner

Now, deep-scanning of your email code is simple. Fix broken tags, missing elements, and structural issues in minutes.

Learn More

Email Rendering Preview Engine

Watch how your email appears across different screen sizes and email clients, and check spot layout issues early.

Learn More

CSS & Compatibility Checker

Analyses CSS support and email client compatibility to tackle rendering problems across major inbox platforms.

Learn More

FAQ

Frequently Asked Questions

Everything you need to know about TrueSend's HTML Email Checker

Why do my emails look different in Gmail and Outlook?

Different email clients render HTML differently. You can use HTML Email Checker to preview and test rendering across all major inboxes before sending.

How do I know if my email HTML is broken?

You can run your HTML through a validator. It will instantly detect missing tags, CSS errors, and layout issues that break your email.

How can I test emails before sending campaigns?

If you run pre-send HTML checks, you can easily catch errors early in the workflow before sending an email campaign.

Is automated email testing really necessary?

Yes, it is highly important to use automated HTML to ensure consistent, error-free emails at scale, especially for scaling campaigns where errors increase.

Who should use an HTML Email Checker?

An HTML checker is useful for email marketers, developers, CRM teams, and SaaS companies who run regular email campaigns.

HTML Email Checker

Send professional-looking
emails with HTML Checker

Powerful HTML Checker for Better Emails

HTML Code Validation

Responsive Email Preview

Compatibility Testing

Auto-Fix Recommendations

Check Your Email HTML in 3 Simple Steps

Paste or Upload Your Email HTML

Scan for Errors & Compatibility Issues

Preview, Fix & Launch Your Campaign

Automate Email HTML Checks with API

Complete HTML Checker Toolkit

HTML Structure Scanner

Email Rendering Preview Engine

CSS & Compatibility Checker

Frequently Asked Questions

Deliver Your Best Work With TrueSend

HTML Email Checker

Send professional-looking emails with HTML Checker

Powerful HTML Checker for Better Emails

HTML Code Validation

Responsive Email Preview

Compatibility Testing

Auto-Fix Recommendations

Check Your Email HTML in 3 Simple Steps

Paste or Upload Your Email HTML

Scan for Errors & Compatibility Issues

Preview, Fix & Launch Your Campaign

Automate Email HTML Checks with API

Complete HTML Checker Toolkit

HTML Structure Scanner

Email Rendering Preview Engine

CSS & Compatibility Checker

Frequently Asked Questions

Deliver Your Best Work With TrueSend

Send professional-looking
emails with HTML Checker