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

# Set global fallback chain

> Set or clear the account-level fallback chain. When set, this chain is used as the default fallback for all rewrite requests that do not include an x-lava-fallbacks header. Pass null to clear the setting. Maximum 5 entries.



## OpenAPI

````yaml /openapi.json patch /account/fallback
openapi: 3.0.0
info:
  title: Lava API
  description: >-
    Lava API enables businesses to implement usage-based billing for AI
    services. This API allows tracking, managing, and billing for third-party AI
    API usage through a forwarding system.
  version: 1.0.0
  contact:
    name: Lava support
    url: https://www.lava.so/contact
servers:
  - url: https://api.lava.so/v1/
    description: Lava API v1
security: []
tags:
  - name: Authentication
  - name: Core Endpoints
  - name: Models
  - name: Services
  - name: Requests
  - name: Wallet
  - name: Payment Methods
  - name: Spend Keys
  - name: Usage
  - name: Checkout Sessions
  - name: Customers
  - name: Plans
  - name: Subscriptions
  - name: Meters
  - name: Webhooks
  - name: Secret Keys
  - name: Credit Bundles
  - name: Gateway Settings
  - name: Skills
  - name: News Data
  - name: Search
  - name: Enrich
paths:
  /account/fallback:
    patch:
      tags:
        - Gateway Settings
      summary: Set global fallback chain
      description: >-
        Set or clear the account-level fallback chain. When set, this chain is
        used as the default fallback for all rewrite requests that do not
        include an x-lava-fallbacks header. Pass null to clear the setting.
        Maximum 5 entries.
      operationId: setAccountFallback
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                fallback_chain:
                  nullable: true
                  type: array
                  description: Fallback chain entries, or null to clear
                  items:
                    type: object
                    properties:
                      url:
                        type: string
                        example: api.openai.com/v1/chat/completions
                        description: Scheme-less provider URL
                      model:
                        type: string
                        example: gpt-4o-mini
                        description: Model name to inject
                    required:
                      - url
                      - model
              required:
                - fallback_chain
      responses:
        '200':
          description: Fallback chain updated
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: true
        '400':
          description: Invalid fallback chain
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '401':
          description: Unauthorized
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
      security:
        - Auth: []
components:
  schemas:
    Error:
      type: object
      properties:
        error:
          type: object
          properties:
            message:
              type: string
              description: Human-readable error message describing what went wrong
              example: Invalid authentication credentials
            code:
              type: string
              description: Machine-readable error code describing what went wrong
              example: forward_token_json_invalid
            status:
              type: integer
              description: HTTP status code of the error
              example: 400
            issues:
              type: array
              items:
                type: object
                properties:
                  path:
                    type: array
                    items:
                      type: string
                    description: Path to the field that caused the validation error
                  message:
                    type: string
                    description: Error message describing the validation issue
                required:
                  - path
                  - message
              description: >-
                Optional array of specific validation issues with their paths
                and messages
              example:
                - path:
                    - model
                  message: 'Missing required field: model'
                - path:
                    - messages
                    - '0'
                    - content
                  message: Invalid message content format
          required:
            - message
            - code
            - status
      required:
        - error
  securitySchemes:
    Auth:
      type: http
      scheme: bearer
      description: >-
        Bearer token authentication used for standard API calls. Format: 'Bearer
        YOUR_API_KEY'

````