mcp-server-apollo

MCP (Model Context Protocol) server for the Apollo.io B2B discovery and enrichment API: company search, people search, contact enrichment (emails/phones), organization firmographics, and API usage stats.

The server wraps Apollo's REST API with one account-level API key kept server-side. It is read-only by design: no sequences, no emailer, no CRM writes, no account management.

Tools

Notes that save you a support ticket:

• People search returns no contact data. Apollo's current mixed_people/api_search endpoint deliberately obfuscates last names and omits emails/phones. Feed the returned person id into apollo_person_enrich to get contact data (that is what costs credits).

• Phone reveals are asynchronous. reveal_phone_number=true requires a public HTTPS webhookUrl; Apollo POSTs the numbers there minutes later. The synchronous response carries a request_id — poll apollo_webhook_result with it if the callback is missed (results kept 30 days).

• Master API key. apollo_people_search and apollo_credit_usage require a master Apollo API key (Apollo returns 403 API_INACCESSIBLE otherwise).

• No credit-balance API. Apollo only exposes per-endpoint rate-limit usage; the remaining credit balance lives in the Apollo UI (Settings → Billing).

• Field projection. Every data tool accepts fields[] dot-paths to shrink responses; company search applies a slim default projection (pass ["*"] for full records).

Related MCP server: apollo-io-mcp-server

Usage

npm install
npm run build

# stdio transport (Claude Desktop, local MCP clients)
APOLLO_API_KEY=... node dist/transports/stdio.js

# streamable HTTP transport on :3000/mcp
APOLLO_API_KEY=... MCP_HTTP_TOKEN=... node dist/transports/http.js

Configuration (see .env.example): APOLLO_API_KEY (required), APOLLO_TIMEOUT_MS, APOLLO_AUDIT_LOG (JSONL audit trail; hashed targets, never raw arguments or secrets), and for HTTP: MCP_HTTP_HOST, PORT, MCP_HTTP_TOKEN (static bearer), MCP_ALLOWED_ORIGINS, MCP_MAX_BODY_BYTES.

There is also an embeddable gateway export (mcp-server-apollo/gateway) that exposes the same tools as plain functions with JSON-schema definitions.

Security

• The API key is read only from the server environment, sent only in the x-api-key header over HTTPS, and redacted from error messages and logs.

• Tool calls pass a policy allowlist; anything unlisted is denied.

• All tools are annotated read-only/non-destructive; credit-consuming tools state their cost in the description so agents confirm spend with the user.

• HTTP transport binds to loopback by default, validates Origin, caps body size, and supports a static bearer token for upstream auth proxies.

• Rate limits: HTTP 429 is retried with jittered backoff honouring retry-after; bulk enrichment runs at low bounded concurrency because Apollo limits bulk_match hard (documented 20/min).

Development

npm run typecheck
npm test
npm run smoke:live   # needs a real APOLLO_API_KEY; uses ~1 credit

License

Apache-2.0