# Customer.io

> Probe-verified (tier 2 of 3). Last checked 2026-08-22. 4 of 5 capability checks passed.

- host: customer.io
- url: https://customer.io/
- category: customer engagement platform
- type: saas
- language: en

## Probe-verified · tier 2 of 3

Probed live on 2026-08-22 against rubric v1. 4 of 5 checks passed.

- PASS — Markdown negotiation
- fail — Markdown twin at a predictable URL
- PASS — llms.txt
- PASS — API catalog
- PASS — MCP server answers

## Unverified actions

Read from the page's own content, with the wording each was drawn from. Inference is kept separate from tested facts; an agent completing the action is tier 3.

- **book** — "Book a demo"

## Summary

Customer.io is a platform for creating personalized customer journeys across multiple messaging channels using AI and automation.

## Context

7 sites in this index share the category "customer engagement platform"; 2 are transactional.

## How we grade

- tier 1 — **Declared**: The site says agents are welcome in its robots.txt. A permission, not a capability.
- tier 2 — **Probe-verified** (this site): We fetched the site and tested each signal ourselves. Dated, repeatable, re-checked on a schedule.
- tier 3 — **Behaviourally verified**: An agent completed the action end to end — booked, bought, submitted — and it worked.

## About this record

Known-Good probes sites live and publishes what was tested and when.
Method: https://knowngood.sh/about.md · Rubric: https://knowngood.sh/benchmark