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Retell AI Create Retell Llm API

The Create Retell Llm API from Retell AI — 1 operation(s) for create retell llm.

Retell AI Create Retell Llm API is one of 78 APIs that Retell AI publishes on the APIs.io network, described by a machine-readable OpenAPI specification and an AsyncAPI event-driven specification.

Tagged areas include Create Retell Llm. The published artifact set on APIs.io includes an OpenAPI specification, API documentation, an AsyncAPI specification, and pricing.

This API exposes 1 operation across 1 path, and defines 44 schemas. It is described by OpenAPI 3.2.0, at version 3.0.0.

Requests are made against a single base URL, https://api.retellai.com.

1 operations 1 paths 44 schemas 1 POST

Metadata

The identity and technical contract details declared by the specification.

Specification
OpenAPI 3.2.0
API Version
3.0.0
Base URL
https://api.retellai.com
Authentication
HTTP Bearer
License
Resource Areas
1

Authentication & Security 1

Retell AI Create Retell Llm API declares 1 security scheme for authenticating requests. It accepts HTTP bearer tokens (string) (api_key). By default, every request must be authenticated.

  • api_key — Authentication header containing API key (find it in dashboard). The format is "Bearer YOURAPIKEY"

Paths & Operations 1

Across 1 path, the API surfaces 1 operation — 1 POST. Each is listed below with its method, path, parameters, and response codes.

Create Retell Llm 1
POST
/create-retell-llm
Create a new Retell LLM Response Engine that can be attached to an agent. This is used to generate response output for the agent.
createRetellLLM body → 201400401500

Schemas 44

The contract defines 44 schemas that model the data the API accepts and returns. The most detailed are CustomTool (16 properties), AgentSwapTool (12 properties), CodeTool (11 properties), MCPTool (11 properties). Each schema is shown below with its type and property counts.

PostCallAnalysisSetting
string
CustomTool
object
16 properties 3 required
CodeTool
object
11 properties 3 required
MCPTool
object
11 properties 3 required
AnalysisData
CancelTransferTool
object
6 properties 2 required
StateEdge
object
3 properties 2 required
BookAppointmentCalTool
object
6 properties 4 required
WarmTransferPrompt
object
2 properties
EnumAnalysisData
object
6 properties 4 required
NumberAnalysisData
object
5 properties 3 required
MCP
object
5 properties 2 required
SendSMSTool
object
7 properties 3 required
AgentSwapWebhookSetting
string
SmsContent
EndCallTool
object
6 properties 2 required
Tool
SmsContentInferred
object
2 properties
ExtractDynamicVariableTool
object
4 properties 4 required
SmsContentTemplate
object
2 properties 2 required
AgentSwapTool
object
12 properties 4 required
StringAnalysisData
object
6 properties 3 required
BooleanAnalysisData
object
5 properties 3 required
State
object
4 properties 1 required
TransferOptionColdTransfer
object
4 properties 1 required
SmsContentPredefined
object
2 properties
KBConfig
object
2 properties
TransferOptionWarmTransfer
object
10 properties 1 required
PressDigitTool
object
4 properties 2 required
TransferDestinationPredefined
object
3 properties 2 required
RetellLLMResponse
AgentVersionReference
Agent version reference. Supports a numeric version (for example 3) or a tag/environment name (for example "prod"). When a tag is provided, resolution uses tha…
TransferCallTool
object
10 properties 4 required
BridgeTransferTool
object
6 properties 2 required
TransferOptionAgenticWarmTransfer
object
7 properties 2 required
TransferDestination
TransferOption
TransferDestinationInferred
object
2 properties 2 required
ToolParameter
object
The parameters the functions accepts, described as a JSON Schema object. See [JSON Schema reference](https://json-schema.org/understanding-json-schema/) for do…
3 properties 2 required
RetellLlmOverride
object
Override properties for Retell LLM configuration in agent override requests.
10 properties
CheckAvailabilityCalTool
object
6 properties 4 required
NullableLLMModel
stringnull
Available LLM models for agents.
RetellLlmRequest
WarmTransferStaticMessage
object
2 properties

Specification

The full machine-readable OpenAPI contract behind this narrative.

Source

retell-ai-create-retell-llm-api-openapi.yml Raw ↑

Other APIs Retell AI publishes across the network.

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Retell AI Clone Voice API
Retell AI Create Agent API
Retell AI Create Agent Version API
Retell AI Create Batch Call API
Retell AI Create Batch Test API
Retell AI Create Chat Agent API
Retell AI Create Chat API
Retell AI Create Chat Completion API
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Where this information came from

This is an independent, third-party profile of Retell AI Create Retell Llm API, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.

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