Nous Research Models API

openapi: 3.1.0
info:
  title: Nous Research Inference API (Nous Portal) Chat Models API
  version: v1
  description: 'OpenAI-compatible inference API served by Nous Research at https://inference-api.nousresearch.com/v1. Exposes a model catalog and a chat-completions endpoint aggregating Nous Research''s own Hermes models alongside a broad catalog of third-party open and frontier models (OpenRouter-style routing). Requests authenticate with a Nous Portal API key (Bearer token). The API additionally supports the x402 HTTP payment protocol: an un-authenticated request returns HTTP 402 with an `accepts` envelope describing an exact Solana USDC micropayment, enabling pay-per- request agentic access without a pre-provisioned account. This specification was DERIVED by probing the live public API (GET /v1/models returns 200 with the model catalog; POST /v1/chat/completions returns 402 with an x402 payment envelope when unauthenticated). Only endpoints observed on the live host are described here; other OpenAI- compatible routes may exist but were not verified.'
  x-source: https://inference-api.nousresearch.com/v1
  x-derived-by: api-evangelist enrichment pipeline (live probe)
servers:
- url: https://inference-api.nousresearch.com/v1
  description: Nous Research inference API (production)
security:
- bearerAuth: []
tags:
- name: Models
  description: Model discovery and catalog.
paths:
  /models:
    get:
      tags:
      - Models
      operationId: listModels
      summary: List available models
      description: Returns the catalog of models available through the Nous Research inference API, including id, pricing, context length, architecture (input/output modalities), and supported parameters. Public — no authentication required (verified 200 without credentials).
      security: []
      responses:
        '200':
          description: The list of available models.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ModelList'
components:
  schemas:
    ModelList:
      type: object
      properties:
        data:
          type: array
          items:
            $ref: '#/components/schemas/Model'
      required:
      - data
    Model:
      type: object
      description: A model available through the inference API.
      properties:
        id:
          type: string
          example: nousresearch/hermes-4-405b
        canonical_slug:
          type: string
        hugging_face_id:
          type: string
        name:
          type: string
        description:
          type: string
        context_length:
          type: integer
        architecture:
          type: object
          properties:
            modality:
              type: string
            input_modalities:
              type: array
              items:
                type: string
            output_modalities:
              type: array
              items:
                type: string
            tokenizer:
              type: string
        pricing:
          type: object
          description: Per-token prices in USD (string decimals).
          properties:
            prompt:
              type: string
            completion:
              type: string
            input_cache_read:
              type: string
        supported_parameters:
          type: array
          items:
            type: string
      required:
      - id
      - name
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: 'Nous Portal API key supplied as: Authorization: Bearer <key>'