There is a metaphor for the Kin Score I have come to like. When you turn up at a restaurant, you can learn a lot by visiting the bathroom. It gives you an idea of how much attention is being paid to hygiene and detail in the kitchen, the part you cannot see. A vendor’s public API surface works the same way.
I recently watched a room of people work out how they would use that when evaluating partners and vendors. Due diligence and managing risk were two of the themes that came up.
Questions to ask of a score
If you are looking at a vendor, here are some things to work through on its provider page:
- Agent readiness: will your agents be able to use this safely? Check idempotency and error semantics in particular.
- Security and compliance: is the auth model documented? Are scopes published? Is there a regulatory posture to look at, if your industry needs one?
- Discoverability: could your teams and tools find what they need without a sales call?
- Commercial clarity: can you tell what this will cost, and can you read the plans?
- Operational transparency: is there a status page and a changelog you could monitor?
An example
Say you need an SMS provider. The SMS tag gives you a ranked list of 171 providers. Twilio leads at 91.6, followed by Telnyx at 86.1. Further down you find Sinch at 71.5, Bandwidth at 61.0 and Plivo at 38.9. These numbers come from the public provider pages on APIs.io, most of them scored on October 17, 2026. They will move, so click through for the current reading.
That does not mean you should pick the highest score. A lower-scoring provider may have the routes, the price or the support you need. What it gives you is the follow-up questions. For instance, if the facet breakdown shows a provider is low on operational transparency, ask it for its uptime history and how it notifies customers of changes. If the Agent Readiness page shows no idempotency, ask what happens to a message when an agent retries a send.
Renewals are a good moment
I liked the suggestion that this applies to contract renewals as much as to new purchases. You are already at the table, and you have a neutral document to bring. “Your category’s leaders publish machine-readable rate limits and you do not” is a far more useful line than “we would like this to be better.” Add it to the renewal as a specific, dated request.
Giving your procurement team a few of these measures also helps them ask technical questions they would not otherwise think of, without needing an engineer in every meeting.
Being fair to the vendor
Vendors can be scored too low. The public surface does not show everything, particularly with enterprise vendors whose docs sit behind a login. So give them the chance to show you. Providers can also correct their listing on APIs.io, and I want them to. If a score is wrong, tell me.
A good vendor conversation starts with the facts and ends with a better relationship, and that is more valuable than any leverage you might get from a number.
The APIs And MCP Tools For This
You can do all of the above by hand on the site, or have an agent do it. Each of these is a REST operation and an MCP tool:
| Job | REST operation | MCP tool | Plan |
|---|---|---|---|
| Compare vendors and their economics | GET /compare |
compare_providers |
Understanding |
| Check agent safety | GET /providers/{slug}/agent-readiness |
get_agent_readiness |
Understanding |
| Read the plans | GET /plans |
find_plans |
Free |
| Find a stack’s gaps | GET /gaps |
gap_analysis |
Influence |
If a reading of your own company is wrong, report_correction is free and unmetered. Owners can also claim a listing and file disputes through the listing operations.
Paths are relative to https://apis.io/api/v1, and the MCP server is at https://apis.io/mcp. The developer area has getting started, the MCP setup and the plans.
