Customer.io MCP server. Query people, segments, campaigns, and message deliveries; send transactional email or broadcasts.
Add to your MCP config, then reload & authorize:
{
"mcpServers": {
"customerio": {
"url": "https://customerio.usefulapi.io/mcp"
}
}
}| Tool | Type | What it does |
|---|---|---|
customerio_search_customers | read | Search customers Search or list people in your workspace by a Customer.io filter — segment membership or attribute conditions — with cursor pagination. |
customerio_get_customer_attributes | read | Get customer attributes Fetch a single person's full attribute profile (every stored profile field) by their id, cio_id, or email. |
customerio_get_customer_segments | read | Get customer segments List every segment a specific person currently belongs to, so you can see exactly how they are being targeted. |
customerio_get_customer_messages | read | Get customer messages List the messages (deliveries) that have been sent to a single person, with cursor pagination. |
customerio_list_segments | read | List segments List all segments in the workspace with their id, name, and type. |
customerio_list_campaigns | read | List campaigns List every campaign in the workspace along with its configuration and status. |
customerio_get_campaign | read | Get campaign Retrieve a single campaign by id with its full configuration. |
customerio_get_campaign_metrics | read | Get campaign metrics Get delivery and engagement metrics for a campaign over time, bucketed by hour, day, week, or month and filterable by channel. |
customerio_list_messages | read | List messages List sent messages (deliveries) across the workspace, filterable by channel type, campaign, or newsletter. |
customerio_list_exports | read | List exports List the data exports that have been created in the workspace. |
customerio_list_collections | read | List collections List the reusable data collections available in the workspace. |
customerio_send_transactional_email | write | Send transactional email Send a real transactional email from a transactional message template, delivered immediately to the recipient with optional Liquid message data and sender/subject overrides. |
customerio_trigger_broadcast | write | Trigger broadcast Trigger an API-triggered broadcast, delivering to the resolved recipient set with optional Liquid data and recipient-filter overrides. |
customerio_usage_status | Usage status (free-tier meter) Report the caller's current free-tier usage this month: calls used, monthly limit, remaining, and whether the cap is reached. Read-only; does not count against the meter. | |
customerio_upgrade | Upgrade to Pro (unlimited) Subscribe to the Pro plan for UNLIMITED Customer.io tool calls (the free tier caps monthly usage). Choose monthly ($9/month) or yearly ($90/year — 2 months free) billing. Returns a Stripe Checkout link to open in your browser; after payment your account upgrades automatically. Read-only; does not count against the meter. |
| Plan | Price | Limit |
|---|---|---|
| Free | $0 | 100 tool calls / month |
| Pro | $9/mo · $90/yr | Unlimited |
This is a Model Context Protocol endpoint — meant to be connected from an AI client, not opened in a browser. An invalid_token response at the URL is the auth gate working as designed; clients authenticate automatically.