curl -sS "$FIDDLER_URL/v3/cost/evaluators" \
  -H "Authorization: Bearer $FIDDLER_TOKEN" \
  | jq '.data'

{
  "data": {
    "items": [
      {
        "project_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "project_name": "my-genai-project",
        "application_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "application_name": "my-assistant",
        "application_creator": {
          "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
          "email": "jsmith@example.com",
          "full_name": "<string>"
        },
        "evaluator_rule_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "evaluator_rule_name": "faithfulness-judge",
        "tokens": {
          "input": 12400,
          "output": 3100,
          "total": 15500
        },
        "cost_usd_estimated": 0.0034
      }
    ],
    "meta": {
      "time_range": {
        "start": "2026-08-01T00:00:00Z",
        "end": "2026-09-01T00:00:00Z"
      },
      "earliest_available_data": "2026-07-01T00:00:00Z",
      "disclaimer": "Cost estimates are based on LiteLLM open-source pricing tables, may lag provider changes, and should not be treated as exact billing.\n"
    },
    "page_size": 10,
    "item_count": 10,
    "total": 100,
    "page_count": 10,
    "page_index": 1,
    "offset": 0
  },
  "api_version": "3.0",
  "kind": "PAGINATED"
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

Evaluator Costs

Get evaluator cost roll-ups

Returns a paginated list of per-evaluator LLM cost and token-usage totals for the requested time window.

Data source. All figures are sourced from Fiddler’s evaluator cost pipeline, which aggregates LLM call records hourly. Results are pre-aggregated totals for the requested window; individual call-level records are not returned by this endpoint.

What appears in items[]. Only evaluator rules that have made at least one billable LLM call within the requested window appear. Non-LLM-backed evaluators (embedding, PII detection, FTL trust models, etc.) never write cost rows and are silently absent — omission is semantically distinct from a zero. Deleted rules are included with both evaluator_rule_id and evaluator_rule_name null (cost is a spend ledger; deletion does not retract it).

cost_usd_estimated. Present on every item; null when unpriced (provider did not return pricing information). A null value is not the same as zero.

UTC-hour snapping. Cost data is collected at hourly boundaries, so start_time is snapped down to the containing UTC hour and end_time is snapped up. The effective, snapped window is echoed back in data.meta.time_range.

RBAC. Org Admins see every application in the organization. All other callers see only applications in projects they can read (APPLICATION: READ, held by Project Admin, Writer, and Viewer roles). A caller with no project access receives an empty 200 for any well-formed project_id or application_id, including unknown and cross-organization ones — the access filter runs before the ID check. An unknown or cross-organization ID for a caller who can read projects returns 400 — not 403 — to avoid acting as an existence oracle. A same-organization ID the caller cannot read returns an empty 200; a malformed ID is still 400.

Availability. The endpoint returns 503 when the evaluator cost feature is not enabled on your Fiddler instance. Contact your Fiddler Customer Success Manager if you receive this status.

GET

cost

evaluators

curl -sS "$FIDDLER_URL/v3/cost/evaluators" \
  -H "Authorization: Bearer $FIDDLER_TOKEN" \
  | jq '.data'

{
  "data": {
    "items": [
      {
        "project_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "project_name": "my-genai-project",
        "application_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "application_name": "my-assistant",
        "application_creator": {
          "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
          "email": "jsmith@example.com",
          "full_name": "<string>"
        },
        "evaluator_rule_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "evaluator_rule_name": "faithfulness-judge",
        "tokens": {
          "input": 12400,
          "output": 3100,
          "total": 15500
        },
        "cost_usd_estimated": 0.0034
      }
    ],
    "meta": {
      "time_range": {
        "start": "2026-08-01T00:00:00Z",
        "end": "2026-09-01T00:00:00Z"
      },
      "earliest_available_data": "2026-07-01T00:00:00Z",
      "disclaimer": "Cost estimates are based on LiteLLM open-source pricing tables, may lag provider changes, and should not be treated as exact billing.\n"
    },
    "page_size": 10,
    "item_count": 10,
    "total": 100,
    "page_count": 10,
    "page_index": 1,
    "offset": 0
  },
  "api_version": "3.0",
  "kind": "PAGINATED"
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

{
  "api_version": "3.0",
  "kind": "ERROR",
  "error": {
    "code": 400,
    "message": "Resource Not Found",
    "errors": [
      {
        "reason": "ResourceNotFoundException",
        "message": "Resource Not Found",
        "help": "<string>"
      }
    ]
  }
}

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Query Parameters

start_time

string<date-time>

Inclusive lower bound, ISO 8601 with timezone offset or Z (a naive timestamp returns 400). Defaults to end_time − 30 days when omitted. Snapped down to the containing UTC hour before querying. A range longer than 366 days returns 400. Either bound may be supplied alone.

end_time

string<date-time>

Exclusive upper bound, ISO 8601 with timezone offset or Z (a naive timestamp returns 400). Defaults to now (UTC) when omitted. Snapped up to the next UTC hour boundary before querying. The current partial hour is always empty — cost rows are written at the close of each hour. start_time >= end_time returns 400.

group_by

enum<string>

default:both

Controls the grouping granularity of items[]. One of:

both (default) — one item per (application, evaluator rule).
application_id — one item per application, costs summed across all evaluator rules in that application.
project_id — one item per project, costs summed across all applications and evaluator rules in that project.

Available options:

project_id,

application_id,

both

project_id

string<uuid>

Filter results to a single project. A project in your organization that you cannot read returns an empty 200. An unknown or other-organization ID returns 400, except for a caller who can read no projects, who gets an empty 200 for any well-formed ID.

application_id

string<uuid>

Filter results to a single application. An application in your organization that you cannot read returns an empty 200. An unknown or other-organization ID returns 400, except for a caller who can read no projects, who gets an empty 200 for any well-formed ID.

limit

integer

default:100

Page size. Defaults to 100. Maximum 500 — requests above 500 return 400.

Required range: 1 <= x <= 500

offset

integer

Offset for the pagination

Response

Paginated evaluator cost items for the requested window. Returns an empty items array (not an error) when there is no data or the caller has no authorized applications.

Response object for paginated API responses.

data

object

required

Paginated evaluator cost roll-up. Extends the standard PaginatedApiResponse data envelope with an items array and a meta block.

Show child attributes

api_version

enum<string>

default:3.0

API version of the response.

Available options:

2.0,

3.0

kind

enum<string>

default:PAGINATED

Type of response, indicating a paginated response.

Available options:

PAGINATED