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

# Create embeddings (OpenAI-compatible)

> Drop-in compatible with OpenAI's Embeddings API. Requires a model whose `output_modality` is `embedding` (see GET /v1/models); text models return 400. Billed on input tokens only.



## OpenAPI

````yaml /openapi.yaml post /v1/embeddings
openapi: 3.1.0
info:
  title: Impossibl AI API
  version: 0.0.1
  description: >
    The Impossibl AI API is one API for all AI providers, OpenAI-compatible
    across OpenAI,

    Anthropic, Google, xAI, and more (`GET /v1/models` lists the full catalog),

    billed from a prepaid credit balance.


    Provider usage is billed at provider list prices with no usage markup.

    Prepaid credit purchases charge a separate fixed 5% platform fee before tax.


    **Agent quickstart**

    1. `POST /v1/accounts` — create a funded account; you get an API key and a
       signup-bonus balance in one call (no human step required).
    2. Call `POST /v1/chat/completions`, `POST /v1/responses`, or
       `POST /v1/audio/transcriptions` with
       `Authorization: Bearer <key>` and a `provider/model` id from `GET /v1/models`.
    3. Credits are deducted per request by token or audio-duration usage; check
    `GET /v1/account`.
servers:
  - url: https://api.impossibl.com
    description: Production
  - url: http://localhost:8787
    description: Local dev
security:
  - BearerKey: []
paths:
  /v1/embeddings:
    post:
      summary: Create embeddings (OpenAI-compatible)
      description: >-
        Drop-in compatible with OpenAI's Embeddings API. Requires a model whose
        `output_modality` is `embedding` (see GET /v1/models); text models
        return 400. Billed on input tokens only.
      operationId: createEmbedding
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/EmbeddingsRequest'
      responses:
        '200':
          description: A `list` of embedding objects, in the same order as `input`.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/EmbeddingsResponse'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '402':
          $ref: '#/components/responses/InsufficientCredits'
        '404':
          $ref: '#/components/responses/UnknownModel'
        '502':
          $ref: '#/components/responses/UpstreamError'
        '503':
          $ref: '#/components/responses/ProviderNotConfigured'
components:
  schemas:
    EmbeddingsRequest:
      type: object
      required:
        - model
        - input
      properties:
        model:
          type: string
          example: openai/text-embedding-3-small
        input:
          description: >-
            One string, or a batch of them. Pre-tokenized (integer array) input
            is not supported.
          oneOf:
            - type: string
            - type: array
              items:
                type: string
        encoding_format:
          type: string
          enum:
            - float
            - base64
          default: float
          description: >-
            `base64` returns each vector as base64-encoded little-endian float32
            instead of a JSON number array.
        dimensions:
          type: integer
          description: >-
            Shorten the output vector. Defaults to the model's native size (1536
            for 3-small, 3072 for 3-large).
        user:
          type: string
          description: Stable per-user id forwarded to the provider for abuse monitoring.
    EmbeddingsResponse:
      type: object
      properties:
        object:
          type: string
          example: list
        model:
          type: string
          example: openai/text-embedding-3-small
        data:
          type: array
          items:
            type: object
            properties:
              object:
                type: string
                example: embedding
              index:
                type: integer
                description: Position of this vector's value in the request `input`.
              embedding:
                description: >-
                  A number array, or a base64 string when `encoding_format` is
                  `base64`.
                oneOf:
                  - type: array
                    items:
                      type: number
                  - type: string
        usage:
          type: object
          description: Embeddings consume input tokens only, so both fields always match.
          properties:
            prompt_tokens:
              type: integer
            total_tokens:
              type: integer
    Error:
      type: object
      properties:
        error:
          type: object
          properties:
            message:
              type: string
            type:
              type: string
              description: >-
                One of authentication_error, invalid_request_error,
                insufficient_quota, upstream_error, provider_not_configured.
  responses:
    BadRequest:
      description: Malformed request (bad JSON, or missing required fields).
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            error:
              message: '`model` and `messages` are required'
              type: invalid_request_error
    Unauthorized:
      description: Missing or invalid API key.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            error:
              message: Invalid API key
              type: authentication_error
    InsufficientCredits:
      description: The account's credit balance is empty. Top up to continue.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            error:
              message: Insufficient credits. Top up to continue.
              type: insufficient_quota
    UnknownModel:
      description: The requested `model` id is not in the registry (see GET /v1/models).
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            error:
              message: 'Unknown model: foo/bar'
              type: invalid_request_error
    UpstreamError:
      description: The upstream provider returned an error.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            error:
              message: 'permission-denied: ...'
              type: upstream_error
    ProviderNotConfigured:
      description: The provider for this model has no API key configured on the gateway.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            error:
              message: 'Provider not configured: missing OPENAI_API_KEY'
              type: provider_not_configured
  securitySchemes:
    BearerKey:
      type: http
      scheme: bearer
      description: Gateway API key (`imp-rt-...`) from POST /v1/accounts or /v1/keys.

````