ListSignal

ListSignal MCP Server

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 10s of millions of 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 rows a month, counts free. No card, no sales call. Get a key (Settings → API Keys).

Tools

One filter grammar, shared with the ListSignal dashboard, its CSV export and the REST API: what a company runs (tech all of, tech_any, tech_not, dns_tech, email_provider), who it is (country, business_model, industry, revenue, employees, language, keyword, min_confidence, min_realness), stores (shopify, has_catalog, min_products, max_products, min_price_avg, max_price_avg, min_new_products_30d), SaaS and hiring (has_pricing, hiring, min_job_count, ats), reachability (has_email, has_named_email, has_phone), quality (min_seo_score, max_seo_score), when (first_seen_after, last_checked_after, discovered, freshness) and what changed (changed_field, changed_kind, changed_value, changed_within). Every filter is documented with an example at listsignal.com/data.

Tool	Costs	What it does
listsignal_count	nothing	How many companies match the filters. Call it first: size a segment, tighten it, then pull.
listsignal_search_companies	rows returned	One page of companies in the target ranking (small real businesses with contact details first), up to the plan's rows a page; total=true adds the count.
listsignal_query	rows returned, limit=0 free	Totals, group_by with counts (business model, country, revenue, employees, industry, mail provider, TLD), chosen fields, up to 500 rows on Pro and Scale.
listsignal_get_company	one row	Everything about one domain: 121 fields, the last 20 changes, each email with its kind and a deliverability verdict, the naming pattern, the people found on the site.
listsignal_changes	rows returned	The change feed, newest first: a technology added or removed, hiring started, a revenue band moved, a site down.
listsignal_dataset_stats	nothing	Live dataset statistics, refreshed every 60 seconds. Citable.

Example prompts that work well:

• "How many Shopify stores in Australia with 300+ products run Klaviyo but not Gorgias, with a person's email on the site?"
• "Find UK SaaS companies that are hiring right now and publish an address"
• "Who went from zero to open roles in the last 30 days in the US, UK, Canada or Australia?"
• "What tech stack does gymshark.com run, and what changed there this month?"

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"

Claude on the web (claude.ai)

claude.ai's connector settings accept a URL only, no headers, so put the key in the URL:

1. Settings → Connectors → Add custom connector
2. Name: ListSignal
3. URL: https://listsignal.com/mcp/k/ls_YOUR_KEY
4. Leave the OAuth fields empty, click Add, then enable it in a chat via the tools menu.

Treat that URL like a password. If it leaks, revoke the key in Settings and create a new one.

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; make one per connector so each can be revoked alone.
• Plans meter rows a month on every surface (dashboard CSV, REST, MCP): Free 1,000 / Starter 2,500 / Pro 15,000 / Scale 75,000. A call costs the rows it returns; counts, group-bys with limit=0 and dataset stats are free and keep working when the month is spent. Rate limits are the plan's searches a minute: 10 / 30 / 120 / 300.
• Contact emails and phones 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.