ListSignal

ListSignal MCP Server

[MCP] [API] [Free tier]

B2B data intelligence for AI agents. ListSignal is a business intelligence / sales intelligence MCP server: technographics, technology detection, Shopify app detection, company and domain enrichment, firmographics (revenue and employee estimates), hiring signals with posting dates, SEO scores, and contact data for 16M+ online businesses. Discovery runs on Certificate Transparency (CT) logs, so new companies appear within hours of going live.

Questions this server answers directly:

• What technology does a website use? (tech stack lookup for any domain)
• Find companies using [technology] (Shopify, Klaviyo, HubSpot, 230+ more)
• Detect Shopify apps on a store (260+ apps tracked)
• Domain to company data (revenue bracket, employees, industry, country)
• Which companies matching my ICP are hiring right now?

This is the official, first-party MCP server for ListSignal, hosted at https://listsignal.com/mcp (remote Streamable HTTP, no install needed).

Free tier: 1,000 calls/month. No card, no sales call. Get a key (Settings → API Key).

Tools

Example prompts that work well:

• "Find SaaS companies in France using HubSpot that are hiring"
• "What tech stack does gymshark.com run, and are they hiring?"
• "Build me a list of US Shopify stores using Klaviyo with $1M-$10M revenue"

Setup

Claude (Desktop / Code)

{  "mcpServers": {    "listsignal": {      "type": "http",      "url": "https://listsignal.com/mcp",      "headers": { "Authorization": "Bearer ls_YOUR_KEY" }    }  }}

Claude Code one-liner:

claude mcp add --transport http listsignal https://listsignal.com/mcp \  --header "Authorization: Bearer ls_YOUR_KEY"

Cursor

Settings → MCP → Add server, or .cursor/mcp.json:

{  "mcpServers": {    "listsignal": {      "url": "https://listsignal.com/mcp",      "headers": { "Authorization": "Bearer ls_YOUR_KEY" }    }  }}

Clients without native HTTP support (stdio bridge)

{  "mcpServers": {    "listsignal": {      "command": "npx",      "args": ["-y", "mcp-remote", "https://listsignal.com/mcp",               "--header", "Authorization: Bearer ls_YOUR_KEY"]    }  }}

Auth, limits, errors

• Auth: Authorization: Bearer ls_... (or X-API-Key). Keys are created in Settings after free signup.
• Quotas: Free 1,000 / Starter 5,000 / Pro 25,000 calls per month. Only successful calls count. Rate limits: 30/60/120 per minute.
• Contact emails are returned on paid plans; the free tier gets contactability and counts.
• Tool errors are returned in-band with actionable messages, so agents self-correct in one retry.

REST API

The same data is available as a plain REST API, documented at listsignal.com/developers with an OpenAPI 3.1 contract at listsignal.com/openapi.json.

Keywords / what this is for

MCP server, Model Context Protocol, B2B data, sales intelligence, business intelligence, domain intelligence, technographics, technology detection, tech stack lookup, Shopify app detection, company enrichment, domain enrichment, competitive intelligence, firmographics, lead generation, Certificate Transparency, ai-agents, llm-tools, Claude, Cursor, agent tools.

About the data

ListSignal discovers businesses from Certificate Transparency logs (so it finds companies the moment they go live), then enriches each domain with technology detection (230+ technologies, 260+ Shopify apps), revenue and employee estimation, business classification, hiring signals from 14,000+ job boards (Greenhouse, Lever, Workday, Personio and more, with posting dates), SEO scoring, and published contact data. Methodology: listsignal.com/scoring/revenue-estimation.