# Retell AI Retell SDK API

> Retell AI Retell SDK API on Apizie: 19 endpoints (Register Call To Get CallId To Establish Connection, Retrieve details of a specific call, Retrieve call details, Create a new agent, …) returned as clean JSON through one API key. Send your own provider key in the x-upstream-key header. Call it over REST at https://apizie.tech/v1/communication:retell-ai/{endpoint} or from Claude, ChatGPT and Cursor through the Apizie MCP server. Free plan: 1,000 requests a month.

- Project key: `communication:retell-ai`
- Category: Communication
- Status: byok
- Source: https://retellai.com
- Page: https://apizie.tech/api/communication/retell-ai
- OpenAPI: https://apizie.tech/api/communication/retell-ai/openapi.json

API for voice AI. Effortlessly integrate human-like Voice AI into your product. | We are building an API that enables your product to provide an intuitive and engaging way for user interaction - through voice.

## Endpoints

### Register Call To Get CallId To Establish Connection
`POST https://apizie.tech/v1/communication:retell-ai/call-establish-connection` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| body | object | yes | JSON request body |

### Retrieve details of a specific call
`GET https://apizie.tech/v1/communication:retell-ai/call-get-details` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| call_id | string | yes | The call id to retrieve call history for. |

### Retrieve call details
`GET https://apizie.tech/v1/communication:retell-ai/call-get-details-2` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| filter_criteria | object | no |  |
| sort_order | string | no | The calls will be sorted by `start_timestamp`, whether to return the calls in ascending or descending order. |
| limit | integer | no | Limit the number of calls returned. |

### Create a new agent
`POST https://apizie.tech/v1/communication:retell-ai/agent-create-new-agent` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| body | object | yes | JSON request body |

### Retrieve details of a specific agent
`GET https://apizie.tech/v1/communication:retell-ai/agent-get-details` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| agent_id | string | yes | Unique id of the agent to be retrieved. |

### List all agents
`GET https://apizie.tech/v1/communication:retell-ai/agent-get-all` (byok)

### Update an existing agent
`POST https://apizie.tech/v1/communication:retell-ai/agent-update-existing-agent` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| agent_id | string | yes | Unique id of the agent to be updated. |
| body | object | yes | JSON request body |

### Delete an existing agent
`POST https://apizie.tech/v1/communication:retell-ai/agent-delete-existing-agent` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| agent_id | string | yes | Unique id of the agent to be deleted. |

### Create a new Retell LLM
`POST https://apizie.tech/v1/communication:retell-ai/retell-new-llm` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| body | object | yes | JSON request body |

### Retrieve details of a specific Retell LLM
`GET https://apizie.tech/v1/communication:retell-ai/retell-get-llm-details` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| llm_id | string | yes | Unique id of the Retell LLM to be retrieved. |

### List all retell LLM
`GET https://apizie.tech/v1/communication:retell-ai/retell-llm-list-all` (byok)

### Update an existing Retell LLM
`POST https://apizie.tech/v1/communication:retell-ai/retell-update-llm` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| llm_id | string | yes | Unique id of the Retell LLM to be updated. |
| body | object | yes | JSON request body |

### Delete an existing Retell LLM
`POST https://apizie.tech/v1/communication:retell-ai/retell-delete-llm` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| llm_id | string | yes | Unique id of the Retell LLM to be deleted. |

### Buy a new phone number & Bind an agent
`POST https://apizie.tech/v1/communication:retell-ai/phone-number-purchase-number-and-bind-agent` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| body | object | yes | JSON request body |

### Retrieve details of a specific phone number
`GET https://apizie.tech/v1/communication:retell-ai/phone-number-get-details` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| phone_number | string | yes | BCP 47 format of the number (+country code, then number with no space, no special characters), used as the unique identifier for phone… |

### List all phone numbers
`GET https://apizie.tech/v1/communication:retell-ai/phone-number-get-all-numbers` (byok)

### Update an existing Retell LLM
`POST https://apizie.tech/v1/communication:retell-ai/phone-number-update-retell-llm` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| phone_number | string | yes | BCP 47 format of the number (+country code, then number with no space, no special characters), used as the unique identifier for phone… |
| body | object | yes | JSON request body |

### Delete an existing phone number
`POST https://apizie.tech/v1/communication:retell-ai/phone-number-remove-phone-number` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| phone_number | string | yes | BCP 47 format of the number (+country code, then number with no space, no special characters), used as the unique identifier for phone… |

### Create a new phone call
`POST https://apizie.tech/v1/communication:retell-ai/call-make-connection` (byok)

| Parameter | Type | Required | Description |
|---|---|---|---|
| body | object | yes | JSON request body |

## Example
```
curl "https://apizie.tech/v1/communication:retell-ai/call-establish-connection" \
  -H "x-api-key: $APIZIE_KEY" \
  -H "x-upstream-key: $PROVIDER_KEY"
```

## FAQ

### How do I call the Retell AI Retell SDK API?
Create a free Apizie key, then send POST https://apizie.tech/v1/communication:retell-ai/call-establish-connection with the header x-api-key. Every endpoint returns { project, data, timestamp }.

### Is the Retell AI Retell SDK API free on Apizie?
Yes. The Free plan includes 1,000 requests a month at 100 requests a minute, no credit card. Retell AI Retell SDK itself also needs your own key from api.retellai.com.

### Can AI agents use the Retell AI Retell SDK API?
Yes. Add the Apizie MCP server (https://apizie.tech/mcp) to Claude, ChatGPT, Cursor or VS Code, then ask in plain language. The agent calls run_scraper with project key communication:retell-ai.

### What is the status of the Retell AI Retell SDK API?
Needs your own provider key (bring your own key)