seolint
seolint

Your HTML, linted for search.

seolint lints the HTML you build. It finds what search engines trip on.

$ npx seolint public Get started
public/blog/launch/index.html✘ 7⚠ 2
6<title>Our new sourdough is here</title>The title must include the brand name
7<meta name="description" content="Our new sourdough loaf is here…"/>
13<meta property="og:image" content="http://example.com/og/sourdough.png"/>Must be an absolute https:// URL
23<h1>Our new sourdough is here</h1>
24<img src="/sourdough.jpg"/>Must have an `alt` attribute
25…or see the <a href="/Menu.html">full menu</a>Must point to a file that exists, not /Menu.html
26<h3>Ingredients</h3>Must not skip from <h1> to <h3>
28<img src="http://example.com/oven.jpg" alt="Our stone oven"/>Must load "src" over https://

One command, every page.

Point it at your build folder. It lints each page, then the whole site. Errors fail the run. Warnings do not.

This is the real output for the example site in the seolint repository.

79 rules, from <title> to the sitemap.

Each rule has its own page in the rules reference. The page says what the rule checks, why it matters, and how to change it.

On every page

Titles, descriptions, and canonical links.The viewport, headings, robots, and images.Links, mixed content, hreflang, Open Graph, and Twitter cards.

Across the whole site

Titles and descriptions that two pages share.Links to files that do not exist.A robots.txt that blocks every crawler, and pages missing from sitemap.xml.

link13 rules canonical10 rules site9 rules description8 rules title6 rules viewport6 rules hreflang5 rules html5 rules og5 rules image4 rules heading3 rules robots2 rules jsonld1 rule mixed1 rule twitter1 rule

Typed config, your own rules.

Rule names and options are type-checked. Plugins use the same API as the built-in rules. 

import * as config from "seolint/config";
import * as presets from "seolint/presets";

export default config.define({
  host: "https://example.com",
  presets: [presets.strict],
  rules: { "og.*": "warn" },
});

Comments on the pull request.

Run it with --format ci in GitHub, Gitea, or Forgejo Actions. Each failure shows on its file and line.

public/blog/launch/index.html
25 <a href="/Menu.html">full menu</a>
site.link.existsMust point to a file that exists, not /Menu.html

Start strict, or start small.

A preset is a config that yours merges in first. You can also share your own across sites.

strict

Every rule that defaults to a warning becomes an error.

essentials

Only the rules that directly affect search results.

staging

Allows noindex on staging and preview deploys.

Fast enough to run on every push.

Measured on 1,200 real pages, 478 MB of HTML, on an Apple M1 Max. Large sites lint in worker threads.

1.0sBun 1.4.4, whole site
1.5sNode 26.12.1, whole site
9site-wide checks

Get started.

seolint needs Node 22.8 or later, or Bun.

  1. Install it.
    npm install --save-dev seolint
  2. Lint your build.
    npx seolint public --host https://example.com
  3. Add it to CI.
    - run: npx seolint public --format ci

Next, follow the quickstart, set up your config, or browse the rules reference.