curl --request GET \
--url https://api.usenexio.com/api/v1/engines/{engine_slug}/versions \
--header 'Authorization: Bearer <token>'import requests
url = "https://api.usenexio.com/api/v1/engines/{engine_slug}/versions"
headers = {"Authorization": "Bearer <token>"}
response = requests.get(url, headers=headers)
print(response.text)const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};
fetch('https://api.usenexio.com/api/v1/engines/{engine_slug}/versions', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));{
"versions": [
{
"version": "1.0",
"released_at": "2026-07-10T12:00:00Z",
"changelog": "Initial generic fixture-engine contract.",
"request_schema_hash": "ddb18d50ae06c1a59bcfed45357bde5e11d323bff873420beca76069106bf8d5",
"response_schema_hash": "71a63e58737dbb2debe6d162dcac7bee729b4a24de2d25106887339f3d485ef2",
"is_breaking_from_previous_major": false,
"gate_verified": true
}
]
}List engine versions
List an engine’s released versions, newest first.
curl --request GET \
--url https://api.usenexio.com/api/v1/engines/{engine_slug}/versions \
--header 'Authorization: Bearer <token>'import requests
url = "https://api.usenexio.com/api/v1/engines/{engine_slug}/versions"
headers = {"Authorization": "Bearer <token>"}
response = requests.get(url, headers=headers)
print(response.text)const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};
fetch('https://api.usenexio.com/api/v1/engines/{engine_slug}/versions', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));{
"versions": [
{
"version": "1.0",
"released_at": "2026-07-10T12:00:00Z",
"changelog": "Initial generic fixture-engine contract.",
"request_schema_hash": "ddb18d50ae06c1a59bcfed45357bde5e11d323bff873420beca76069106bf8d5",
"response_schema_hash": "71a63e58737dbb2debe6d162dcac7bee729b4a24de2d25106887339f3d485ef2",
"is_breaking_from_previous_major": false,
"gate_verified": true
}
]
}Authorizations
Send the key as Authorization: Bearer <key>. Two kinds of key exist.
Organization keys are issued in the portal (Settings, then API keys),
each bound to one environment, shaped nx_<environment slug>_<64 hex>. They carry
no capabilities and pass every capability check, with one exception:
routes under /records, /actions, /operations,
/api/v1/engines/{id}/opportunities, /api/v1/graph and
/api/v1/catalog/documents accept an
organization key only when its environment is live, and refuse any
other with 403 scoped_key_required. Revocation takes effect within 60
seconds.
Scoped keys are issued by Nexio on request, shaped
nxsk_v1_<24 hex key id>_<43 character secret>. Each is bound to one
org, one environment, a set of engines and a set of capabilities. A
malformed, unknown or revoked nxsk_ key fails with 401 and is never
retried as an organization key. Revocation takes effect on the next
request. A scoped key without a route's capability gets 403
insufficient_capability; a scoped key not bound to the engine gets 403
engine_binding_forbidden.
Key-grantable capabilities: engines:read, runs:write, runs:read,
runs:defensibility:read, runs:test, catalog:read,
catalog:documents:read, webhooks:manage, conversations:use,
conversations:export, records:read, records:opportunities:run,
actions:write, actions:read, graph:read, records:analyze.
Routes that accept organization keys only (every scoped key gets 403
insufficient_capability): environment management, engine create,
update, configuration and publish, and conversation instance
authoring. Each operation description names the capability a scoped
key needs.
Path Parameters
Engine identifier slug (e.g. default).
Response
Versions, newest first.
Hide child attributes
Hide child attributes
Two-tier major.minor identifier (e.g. 1.0, 1.3, 2.0).
^\d+\.\d+$When the version row was created.
Operator-supplied human-readable summary of what changed.
True only when this is a *.0 row AND a prior major ((major-1).*)
also exists for the same engine. The first-ever release of an
engine reports false.
True only on an engine's first release when the eval gate verified the candidate against a labeled evaluation set. Later releases report false.
SHA-256 of the exact normalized released request schema bytes.
^[0-9a-f]{64}$SHA-256 of the exact normalized released response schema bytes.
^[0-9a-f]{64}$Actor recorded at publish: a dashboard user ID for dashboard
publishes, api_key:<id> for API publishes. Omitted on
backfilled rows with no recorded actor.
The evaluation set that verified the release. Present only when gate_verified is true.