Apollo.io MCP Server

FastMCP server exposing the full operational surface of the Apollo.io REST API to Claude Code. 27 tools covering sequences, campaign health, mailbox warmup, people/org enrichment, CRM contacts, tasks, labels, credit tracking, AND programmatic template/sequence/mailbox-cap editing with audit logging.

Most existing Apollo MCPs only expose people search and enrichment. This one is built for teams running outbound at scale — daily health digests, sequence management, mailbox deliverability monitoring, programmatic contact enrollment, and end-to-end sequence authoring without touching the Apollo UI.

Quick reference

apollo_campaign_health                — daily digest (start here)
apollo_messages_search days_back=1    — raw send/open/reply/bounce log
apollo_mailbox_warmup                 — per-mailbox deliverability state
apollo_sequences_list                 — all sequences + labels + stats
apollo_sequence_add_contacts ...      — enroll contacts into a sequence
apollo_template_update ...            — update template body + subject (with audit log)
apollo_sequence_create ...            — author a new sequence end-to-end
apollo_step_create ...                — add a step + template to a sequence
apollo_mailbox_update_cap ...         — change daily send cap
apollo_credits_remaining              — monthly credit budget check
apollo_health                         — self-check (also probes master key)

Tool inventory (27)

Campaign health

• apollo_campaign_health(days_back=1) — digest across all sequences + mailboxes
• apollo_mailbox_warmup() — per-mailbox warmup status and daily limits
• apollo_sequence_get(sequence_id) — one-sequence deep-dive

Sequences

• apollo_sequences_list() — list all sequences with stats
• apollo_sequence_add_contacts(sequence_id, contact_ids, send_email_from_email_account_id?)
• apollo_sequence_remove_contacts(sequence_id, contact_ids)
• apollo_sequence_set_active(sequence_id, active) — activate or pause

Messages / analytics

• apollo_messages_search(days_back, sequence_ids?, stats?, per_page, max_pages)

People / orgs

• apollo_people_search(...) — free (no credit burn)
• apollo_person_enrich(...) — 1 credit per revealed email
• apollo_bulk_person_enrich(people, reveal_personal_emails?) — up to 10/call
• apollo_org_search(...)
• apollo_org_enrich(domain)
• apollo_org_job_postings(organization_id)

CRM

• apollo_contacts_search(...)
• apollo_contact_create(...)
• apollo_contact_update(contact_id, fields)
• apollo_contact_stages()

Tasks / labels / credits

• apollo_task_create(...)
• apollo_labels_list()
• apollo_label_create(name)
• apollo_credits_remaining()

Template + sequence authoring (destructive writes)

• apollo_template_get(template_id) — fetch current template state
• apollo_template_update(template_id, subject?, body_text?, body_html?, audit_label?) — update template subject + body. Snapshots current state to APOLLO_AUDIT_LOG_PATH (if set) BEFORE the write so any breakage is reversible from the diff
• apollo_sequence_create(name, label?, permissions?, active?) — create a new sequence (paused by default)
• apollo_step_create(sequence_id, position, wait_days, subject, body_text, body_html?, step_type?, include_signature?) — create a step + touch + template in one call
• apollo_mailbox_update_cap(mailbox_id, daily_send_limit, audit_label?) — change daily send cap on a mailbox. Audits before/after.

Diagnostics

• apollo_health() — probes API key validity + master-key hint

Configuration

Copy config.example.yaml to config.yaml and fill in your values:

cp config.example.yaml config.yaml

config.yaml is gitignored. Key fields:

Env vars:

Install

Open Claude Code, paste:

/plugin marketplace add adelaidasofia/apollo-mcp
/plugin install apollo-mcp@apollo-mcp

Then set APOLLO_API_KEY (must be a master key) in your environment and restart Claude Code.

pip3 install -r requirements.txt
python3 -c "import server; print('OK')"

{
  "mcpServers": {
    "apollo": {
      "command": "python3",
      "args": ["/path/to/apollo-mcp/server.py"],
      "env": {
        "APOLLO_API_KEY": "your-master-key-here"
      }
    }
  }
}

Known gotchas

1. MASTER key required for /emailer_campaigns, /emailer_messages/search, /email_accounts, /usage_stats/*. Standard keys return 403. apollo_health probes for this automatically.

2. Rate limit ~60 req/min. Built-in jittered exponential backoff handles 429s transparently.

3. Pagination hard-capped at 50 pages × 100/page = 5,000 records per call. Slice by date for deeper queries.

4. Credit burn — apollo_person_enrich(reveal_personal_emails=True) and the bulk variant each burn 1 credit.

5. 5-minute in-memory cache for sequences_list, email_accounts, labels, contact_stages. Force-refresh by restarting Claude Code.

6. Cloudflare 1010 on default Python UAs. apollo.io returns HTTP 403 with body error code: 1010 when it sees python-urllib/* or python-httpx/* user-agents. The server spoofs apollo-mcp/1.0 (curl/8.0.0) to bypass. If you build any adjacent scripts hitting apollo.io, add the same User-Agent header or you'll debug a phantom 403 that looks like a missing master key.

7. No working sequence-scoped unenroll endpoint. POST /emailer_campaigns/{id}/remove_contact_ids returns 404. The no-ID variant POST /emailer_campaigns/remove_contact_ids returns 200 but is a silent no-op regardless of payload. The only reliable unenroll path is DELETE /contacts/{id}, which cascades all campaign enrollments. Destructive: the contact record is marked deleted: true. apollo_sequence_remove_contacts wraps this.

8. GET /emailer_campaigns creates an empty sequence. Use POST /emailer_campaigns/search to list sequences. The server does this correctly — just be careful if you hit the API directly.

9. Sequence activation uses PUT, not a sub-resource. The correct endpoint to activate or pause a sequence is PUT /emailer_campaigns/{id} with body {"emailer_campaign": {"active": true/false}}. Sub-resource paths like /check_contacts return 404.

Scripts

• scripts/daily_digest.py — standalone script that pulls yesterday's stats and prepends them to a markdown dashboard. Run via cron or manually.
• scripts/bootstrap_sequences.py — create sequences programmatically from code. Useful for version-controlling email copy. Includes the undocumented POST /emailer_touches/{id}/approve endpoint needed to move steps out of draft state.

Related MCPs

Same author, same architecture pattern (FastMCP, draft+confirm on writes where applicable, vault auto-export, MIT):

• slack-mcp — multi-workspace Slack
• imessage-mcp — macOS iMessage
• whatsapp-mcp — WhatsApp via whatsmeow
• google-workspace-mcp — Gmail / Calendar / Drive / Docs / Sheets
• substack-mcp — Substack writing + analytics
• luma-mcp — lu.ma events
• parse-mcp — markitdown / Docling / LlamaParse router
• rescuetime-mcp — RescueTime productivity data
• graph-query-mcp — vault knowledge graph queries
• graph-autotagger-mcp — wikilink suggestions from the graph
• investor-relations-mcp — seed-raise pipeline tracker
• vault-sync-mcp — bidirectional vault sync

Telemetry

This plugin sends a single anonymous install signal to myceliumai.co the first time it loads in a Claude Code session on a given machine.

What is sent:

• Plugin name (e.g. slack-mcp)
• Plugin version (e.g. 0.1.0)

What is NOT sent:

• No user identifiers, names, emails, tokens, or API keys
• No file paths, message content, or anything from your work
• No IP address is stored after dedup processing

Why: Helps the maintainer know which plugins people actually install, so attention goes to the ones that get used.

Opt out: Set the environment variable MYCELIUM_NO_PING=1 before launching Claude Code. The hook will skip the network call entirely. Already-pinged installs leave a sentinel at ~/.mycelium/onboarded-<plugin> — delete it if you want to reset state.

License

MIT

Built by Mycelium AI. Full install or team version at diazroa.com.