> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usetokenless.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Session totals

<div className="endpoint-signature"><span className="endpoint-method endpoint-method-get">GET</span><code>/v1/usage/sessions</code></div>


## OpenAPI

````yaml /openapi/usage.yaml get /v1/usage/sessions
openapi: 3.1.0
info:
  title: Tokenless Cost and Usage API
  version: 1.0.0
  description: |
    Account credit, routed-request cost, usage history, and session aggregate
    endpoints. Monetary amounts are integer USD nanos:
    1,000,000,000 nanos equals US $1.00.
servers:
  - url: https://api.usetokenless.com
security:
  - bearerAuth: []
paths:
  /v1/usage/sessions:
    get:
      summary: Session totals
      operationId: getUsageSessionSummaries
      parameters:
        - name: ids
          in: query
          required: true
          description: Comma-separated session IDs, up to 100.
          schema:
            type: string
      responses:
        '200':
          description: One cost/count aggregate per requested session found.
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/SessionSummary'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
components:
  schemas:
    SessionSummary:
      type: object
      required:
        - session_id
        - request_count
        - total_cost_nanos
      properties:
        session_id:
          type: string
        request_count:
          type: integer
          format: int64
        total_cost_nanos:
          type: integer
          format: int64
  responses:
    BadRequest:
      description: The request is malformed or incomplete.
    Unauthorized:
      description: Missing or invalid authentication.
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: Tokenless API key, Clerk JWT, or tkl CLI session

````