FMCSA API documentation: where to find it.

FMCSA documents QCMobile on its developer site, endpoint by endpoint, with a WebKey required for every call. CarrierOk documents its own API at developers.carrierok.com with a typed OpenAPI spec, per-field definitions and a free sandbox key, so a response can be read before anything is paid.

The official docs

mobile.fmcsa.dot.gov/QCDevsite covers QCMobile's endpoints and the WebKey. It documents raw FMCSA records, which is all QCMobile returns.

What is missing there

No BASIC percentiles, no ISS score, no insurance history and no change feed, because the API does not return them.

CarrierOk's docs

Every endpoint, field, error code and limit, with a typed OpenAPI spec for code generation and a data dictionary defining each field.

Reading a real response

A free sandbox key is issued at signup with no card and returns every endpoint on fixture data from ten evaluation carriers.

Field counts

The full profile returns 300+ fields; the FMCSA mirror returns exactly 236, null where FMCSA has no value, so every response has the same shape.

What you need → where it’s documented.

One request, the full carrier record.

The CarrierOk API authenticates with a Bearer token in the Authorization header and returns a {"items": […], "total_count"} envelope with flat, snake_case fields, 300+ of them per carrier, refreshed throughout the day.

curl "https://api.carrierok.com/v2/profile?dot_number=1234567" \
  -H "Authorization: Bearer YOUR_API_KEY"

{
  "items": [{
    "dot_number": "1234567",
    "legal_name": "APEX TRANSPORT LLC",
    "usdot_status": "Active",
    "iss_value": "82",
    "iss_recommendation": "INSPECT",
    "basic_percentile_unsafe_driving": 0.84,
    "basic_percentile_vehicle_maintence": 0.83,
    "...": "300+ fields per carrier"
  }],
  "total_count": 1
}

The sandbox returns fixture data for 10 evaluation carriers with no card required.

What the CarrierOk developer docs cover.

Getting a key takes a minute; the walkthrough is at how to get an FMCSA API key. Evaluating the official API instead? Start with the QCMobile API guide or the side-by-side comparison.