Web Validator by DigestSEO — Claude Code MCP server: how to install
Validates HTML and CSS against W3C standards, audits SEO metadata, checks broken links, tests JSON-LD markup, and captures responsive screenshots.
claude mcp add --transport http mcp-web-validator https://web-validator-mcp.digestseo.com/mcpWhat Web Validator by DigestSEO does
The server provides two distinct integration surfaces: a local npm package executed over stdio and a remote Streamable HTTP endpoint hosted at https://web-validator-mcp.digestseo.com/mcp. Local runs require Node.js 22.12.0 or newer.
When operating locally, the package accesses workspace files directly. Tools like html.local and css.local pass file contents to external W3C Nu and Jigsaw validators, while seo.metadata evaluates headings and Open Graph tags locally. The screenshot.capture utility fetches a browser into Puppeteer storage during its initial invocation. You can redirect this storage by setting PUPPETEER_CACHE_DIR.
The hosted endpoint isolates operations inside a worker environment without local filesystem access. It can audit supplied markup or crawl up to eight sitemap pages while respecting robots.txt rules, skipping browser rendering and JavaScript execution altogether.
What it helps with
- validate local HTML and CSS markup against W3C checkers
- detect syntax problems in JSON-LD structured data
- audit Open Graph tags, canonical URLs, and heading hierarchy
- identify broken external links found inside page markup
- generate viewport screenshots across mobile and desktop sizes
Example prompts for the agent
- Run W3C validation on
index.htmland report any syntax errors. - Audit the SEO meta tags and JSON-LD markup inside
template.html. - Take mobile and desktop screenshots of
index.htmland save them to./screenshots.
How to install Web Validator by DigestSEO
1Platform CLI: remote server
claude mcp add --transport http mcp-web-validator https://web-validator-mcp.digestseo.com/mcp2Platform CLI
claude mcp add web-validator-by-digestseo -- npx -y mcp-web-validator1Platform CLI: remote server
codex mcp add web-validator-by-digestseo --url https://web-validator-mcp.digestseo.com/mcp2Platform CLI
codex mcp add web-validator-by-digestseo -- npx -y mcp-web-validatorConfig file
{
"mcpServers": {
"web-validator-by-digestseo": {
"url": "https://web-validator-mcp.digestseo.com/mcp"
}
}
}{
"mcpServers": {
"web-validator-by-digestseo": {
"command": "npx",
"args": [
"-y",
"mcp-web-validator"
]
}
}
}Config file
{
"servers": {
"web-validator-by-digestseo": {
"type": "http",
"url": "https://web-validator-mcp.digestseo.com/mcp"
}
}
}{
"servers": {
"web-validator-by-digestseo": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"mcp-web-validator"
]
}
}
}1Platform CLI: remote server
gemini mcp add -t http web-validator-by-digestseo https://web-validator-mcp.digestseo.com/mcp2Platform CLI
gemini mcp add web-validator-by-digestseo npx -y mcp-web-validatorStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about Web Validator by DigestSEO
How to install Web Validator by DigestSEO in Claude Code?
Add the remote HTTP endpoint by running claude mcp add --transport http web-validator-by-digestseo https://web-validator-mcp.digestseo.com/mcp. Alternatively, configure a local stdio server with claude mcp add web-validator-by-digestseo -- npx -y mcp-web-validator.
What does Web Validator by DigestSEO do?
It audits web code for W3C compliance, inspects JSON-LD blocks, and checks links for HTTP errors. The package also evaluates on-page search metadata and captures PNG screenshots across multiple viewports.
What are the dependencies for taking screenshots?
Capturing screenshots requires the local stdio runner and Puppeteer. Puppeteer downloads its headless browser automatically during the first screenshot call, using PUPPETEER_CACHE_DIR if you set a custom folder.
