What we tested
Probed live on 23 Aug 2026 against rubric v1. 3 of 5 checks passed.
PROBE-VERIFIEDtier 2 of 3
✓Markdown negotiationAccept: text/markdown
—Markdown twin at a predictable URL/page.md
✓llms.txt/llms.txt
✓API catalogRFC 9727
—MCP server answers/.well-known/mcp/server-card.json → tools/list
What an agent could do here
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.
UNVERIFIED
register“SIGN UP FREE →”https://accounts.useinbox.com/signup?culture=en-US
contact“Contact Us — Write Us”https://useinbox.com/contact-us
query_api“Check our API documentation”https://developers.useinbox.com/
Context
13 sites in the index share the category email marketing platform, of which 11 are transactional.
How we grade
Three tiers. Every listing shows which one it has reached, and when. The rubric.
tier 1Declared
The site says agents are welcome in its robots.txt. A permission, not a capability.
tier 2Probe-verified
We fetched the site and tested each signal ourselves. Dated, repeatable, re-checked on a schedule.
tier 3Behaviourally verified
An agent completed the action end to end — booked, bought, submitted — and it worked.
Own this site?
2 checks did not pass when we last looked: Markdown twin at a predictable URL, MCP server answers. Each is a small, specific fix; the rubric says exactly what we look for.
Behavioural verification — an agent completing your booking, purchase or contact flow end to end, with the date published here — opens to a small founding cohort first. Leave an email to be in it.
Related verified sites
NudgenNudgen provides AI-assisted email marketing workflows with campaign controls and API acces
email marketing platform Dreamlit AIDreamlit AI is an AI email marketing platform that creates transactional, lifecycle, and m
email marketing platform SureContactSureContact is an email marketing and contact management platform for WordPress businesses
email marketing platform MailcoachMailcoach is an email marketing platform for sending newsletters, drip campaigns, and tran
email marketing platform LTV.aiLTV.ai is an AI-powered email marketing platform for ecommerce brands to drive repeat purc
email marketing platform SequenzySequenzy is an email marketing platform for developers offering subscriber management, aut
email marketing platform é»åè±¹ NewsleopardNewsleopard provides an automated email and SMS marketing platform with API integration an
email marketing platform Ecomail.czEcomail.cz is a Czech marketing platform for newsletters, SMS, customer data management, a
email marketing platform Record generated from a live database query. Method: about the index.