About: why the Evlio team built Evlio · Evlio

About Evlio
We
documented
APIs
for
20,000
companies.
Docs were never the hard part.
Thousands of teams arrived at Evlio ready to publish, then found nobody could say what their API surface was, who called it, or what would break.
20,000
COMPANIES ON EVLIO
YC
Y COMBINATOR BACKED
Atlassian
VENTURES INVESTOR
Fortune 500
IN PRODUCTION TODAY
TEAMS THAT TRUST EVLIO WHERE APIS CANNOT GO DOWN
Ticketmaster, FIS, Corpay, SimilarWeb. They run on Evlio, and Evlio is the layer they kept asking us for.
2021
Evlio launches
API docs that write themselves
2023
20,000 catalogs
The same six questions, every time
2025
Agents arrive
The human buffer disappears
Now
Evlio
The layer they kept asking for
Why we built it
Why we built Evlio: six questions we could never answer
Teams arrived at the last mile, docs blocking the launch. Then the questions started, and none of them were about docs.
ASKED IN ONBOARDING, AGAIN
01
/
06
“How many endpoints do we actually have?”
“Can we deprecate this one?”
“Is this safe to give a partner?”
“Who broke the integration?”
“Is this API any good?”
“Can an agent use this?”
answer
Nobody knew. The spec covered a third; the rest lived in code three teams had touched.
Unanswerable without grepping every frontend. So it stayed in production forever.
Decided in a meeting, from memory, with no record of which fields they would receive.
A field vanished from a response. Finding the commit and the consumer took days.
No definition of good, no score to argue with. Only opinions, held with varying confidence.
The newest question, and the one that made every question above urgent instead of annoying.
THE QUEUE
How many endpoints do we have?
Can we deprecate this one?
Is this safe to give a partner?
Who broke the integration?
Is this API any good?
Can an agent use this?
Docs were the symptom. The disease is that almost nobody has a system of record for their own APIs.
What agents changed
What agents changed: same bad field name, two very different Tuesdays
A developer, 2019
reads the error, stops
POST
/payouts
{ amount, currency }
← 400
"fee_mode" is required
reads the error
greps the codebase, finds an enum
fixes it once, ships
CALLS
1
DAMAGE
none
An agent, today
incident
POST
/payouts × 60
args mutating
← 400
"fee_mode" is required
guesses fee_mode: "standard"
→
201
no idempotency key, retries anyway
14 duplicate payouts created
reports success to its user
CALLS
60
DUPLICATE PAYOUTS
14
P95
2.4s
Evlio brings your APIs into view, ready for developers and AI agents.
Who is building it
Who is building Evlio: people who have carried the pager for an API
ex-MSFT
Built at Microsoft scale
Where one bad schema decision reaches millions of callers before anyone notices.
ex-GOOG
Operated at Google scale
Thousands of internal services, and the versioning discipline that survives them.
20,000
API catalogs seen
The good, the undocumented, and the ones held together by one engineer’s memory.
∞
Pages carried
Platform leads who ran the gateways and know which parts should never have been manual.
MANIFESTO
four opinions the product is built on
01
The code is the only honest source
A document a human maintains is a document that will be wrong by Thursday.
02
Quality has to be a number
Scoring every endpoint turns an argument into a task list.
03
Governance that cannot say no is theater
A report about a breaking change is not governance. A publish that gets blocked is.
04
Agents are consumers, not a feature
If an agent can call your API, it deserves the same auth, limits, and logs as any partner.
FAQ
Who is behind Evlio?
The team at Evlio, the API documentation platform used by 20,000 companies. Evlio is their answer to what API management needs to become when agents join the consumer list.
Why did we build Evlio?
Years of making API docs readable for humans made the gap obvious: AI agents do not read prose, they read schemas and act on them. Evlio gives APIs the catalog, contracts, and governed access that agents require.
Who operates Evlio?
Evlio is operated by Evlio Inc. The platform lives at evlio.xyz, with documentation at evlio.xyz/docs.
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