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

# List Fallback LLMs

> List large language models that can be used as fallback models.

<span data-api-safety-label="read-only"><Badge color="gray" size="sm" shape="pill">Read only</Badge></span>

<Info>
  **Recommended.** This endpoint is part of the public `/v1` API reference and is the supported path for new integrations. See the [migration guide](/docs/api-reference/v1/migrating-to-v1) for versioning guidance.
</Info>

Lists the language models that can serve as an agent's fallback LLM. A fallback LLM takes over mid-call when the primary model is slow or unavailable, so the conversation keeps going instead of stalling.

## When to use this

* **Configuring fallbacks**: pick a model from this list, then enable it on the agent with `fallback_llm_enabled`, `llm_fallback_model`, and `llm_fallback_delay_ms` via [Create Agent](/docs/api-reference/v1/agents/create) or [Update Agent](/docs/api-reference/v1/agents/update).
* **Validating configuration**: confirm a previously configured fallback model is still offered before publishing an agent change.

Not every model in the main [List LLMs](/docs/api-reference/v1/llms/list) catalog is eligible as a fallback; this endpoint returns only the eligible set. Choose a fallback from a different provider than the primary model so a provider-wide outage does not take out both.

## Result

The response is a plain JSON array of models, not a paginated envelope. Each entry includes the model's `id` and display metadata; use the response schema on this page for the exact fields. See [Errors](/docs/api-reference/errors) for the standard error format.


## OpenAPI

````yaml GET /v1/llms/fallback
openapi: 3.0.0
info:
  title: DialNexa API
  description: >-
    Public REST API for the DialNexa voice AI platform. Versioned endpoints are
    under /v1; unversioned endpoints are legacy and deprecated.
  version: 1.0.0
servers:
  - url: https://api.dialnexa.com
    description: DialNexa production API
security:
  - bearer: []
tags:
  - name: API Keys
  - name: Agent Functions
  - name: Agents V1
  - name: Agents2
  - name: Batch Calls
  - name: Batch Calls V1
  - name: Call Logs
  - name: Calls
  - name: Calls V1
  - name: Campaign Leads
  - name: Campaigns
  - name: External Webhooks
  - name: Knowledge Base
  - name: Knowledge Base V1
  - name: LLMs
  - name: LLMs V1
  - name: Languages
  - name: Languages V1
  - name: Organization Phone Numbers
  - name: Organization Phone Numbers V1
  - name: Phone Number Pricing
  - name: Phone Number Pricing V1
  - name: Transcribers
  - name: Transcribers V1
  - name: User Webhooks
  - name: User Webhooks V1
  - name: V1
  - name: Voices
  - name: Voices V1
  - name: Webcall
  - name: Workflow Leads
  - name: Workflow Leads V1
  - name: Workflows
  - name: Workflows V1
paths:
  /v1/llms/fallback:
    get:
      tags:
        - LLMs
        - LLMs V1
        - V1
      summary: List Fallback LLMs
      description: Returns large language models that can be selected as fallback models.
      operationId: LlmsV1Controller_getFallback
      parameters:
        - name: page
          required: false
          in: query
          schema:
            type: number
            example: 1
        - name: limit
          required: false
          in: query
          schema:
            example: 20
            type: number
        - name: sortBy
          required: false
          in: query
          schema:
            example: id
            type: string
        - name: sortOrder
          required: false
          in: query
          schema:
            enum:
              - ASC
              - DESC
            type: string
      responses:
        '200':
          description: Fallback LLM returned successfully.
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/Llm'
              examples:
                success:
                  summary: Successful response
                  value: []
        '400':
          description: Bad request - invalid query parameters.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              examples:
                error:
                  summary: 400 Bad Request
                  value:
                    statusCode: 400
                    message: Invalid query parameters
                    error: Bad Request
        '401':
          description: Unauthorized.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              examples:
                error:
                  summary: 401 Unauthorized
                  value:
                    statusCode: 401
                    message: API key is missing or invalid
                    error: Unauthorized
        '403':
          description: Forbidden - API key does not have access to this organization.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              examples:
                error:
                  summary: 403 Forbidden
                  value:
                    statusCode: 403
                    message: You do not have permission to access this resource
                    error: Forbidden
        '500':
          description: Internal server error.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              examples:
                error:
                  summary: 500 Internal Server Error
                  value:
                    statusCode: 500
                    message: Internal server error
                    error: Internal Server Error
      security:
        - bearer: []
components:
  schemas:
    Llm:
      type: object
      properties:
        id:
          type: string
          example: llm_abc123
          description: Signed LLM ID
      required:
        - id
    ErrorResponse:
      type: object
      properties:
        statusCode:
          type: integer
          example: 400
        message:
          oneOf:
            - type: string
            - type: array
              items:
                type: string
          example: phone_number must be a valid E.164 phone number
        error:
          type: string
          example: Bad Request
      required:
        - statusCode
        - message
        - error
  securitySchemes:
    bearer:
      scheme: bearer
      bearerFormat: JWT
      type: http

````