> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://respan.ai/docs/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://respan.ai/docs/_mcp/server.

# Create an OpenAI-format chat completion

POST https://api.respan.ai/api/{provider}/v1/chat/completions
Content-Type: application/json

Relay an OpenAI-format chat completions payload to one provider and get that provider's response back byte for byte. Respan authenticates the request, applies your [limits](/docs/documentation/features/gateway/limits), and logs it, but doesn't translate the request or recompute usage. Respan removes `respan_params` and merges a literal `extra_body` object into the body; unknown and provider-only fields are passed through. Streams are relayed frame by frame, and requests time out after 600 seconds.

`{provider}` is a provider with an OpenAI-format API, such as `openai`, `azure_openai`, `xai`, `groq`, `mistral`, `deepseek`, `togetherai`, `fireworks`, or `perplexity`. A provider without an OpenAI-format API returns `404`. A provider with no fixed public endpoint, such as Azure OpenAI, needs the provider URL saved with its key; without it the request returns `400`. Anthropic, Google and OpenRouter have their own endpoints.

Upstream, Respan sends only `accept`, `accept-language`, `content-type`, `user-agent`, and headers that start with `x-` plus the provider ID, with `_` written as `-` (for example `x-azure-openai-`). The response includes `X-Respan-Log-Id`, `X-Respan-Upstream-Request-Id`, and the provider's `x-ratelimit-*` and `retry-after` headers.

Reference: https://respan.ai/docs/apis/gateway/create-openai-format-chat-completion

## Authentication

- `Authorization` header (bearer token, required) — Use your Respan API key for Respan API authentication. Enter only the Respan API key value; clients send Authorization: Bearer \<RESPAN\_API\_KEY>. For /api/responses, provider credentials such as Perplexity, OpenAI, or Azure OpenAI go in Settings -> Providers or respan\_params.credential\_override in the request body, not in this authentication field.

## Request

### Path parameters

- `provider` (string, required) — The provider ID, such as `openai`, `azure_openai`, `xai`, `groq`, `mistral`, `deepseek`, `togetherai`, `fireworks`, or `perplexity`.

### Body (application/json)

This endpoint expects an object.

- `model` (string, required) — The provider's own model ID.
- `messages` (list of map from string to any, required) — Chat messages in OpenAI format.
- `stream` (boolean, optional) — Stream the provider's response as server-sent events.
- `respan_params` (map from string to any, optional) — Respan parameters such as `customer_identifier` or `metadata`. Removed before the request is forwarded.

## Response

### 200

The provider's response, unchanged.

- `map from string to any`

## Errors

### 400 Bad Request Error

No endpoint is known for the provider: save the provider URL with its key. Otherwise, the provider's own `400`.

- `map from string to any`

### 401 Unauthorized Error

No usable key for the provider. The code is `activation_required` when your organization has no credits and no provider key for the model.

- `map from string to any`

### 402 Payment Required Error

The request's customer is over their budget.

- `map from string to any`

### 403 Forbidden Error

The API key is missing, invalid or expired.

- `detail` (string, required)

### 404 Not Found Error

The provider isn't available on this route.

- `map from string to any`

### 429 Too Many Requests Error

Your Respan key's rate limit or an API key limit's block rule, or the provider's own `429`.

- `map from string to any`

## Examples

**Request**

```json
{
  "model": "llama-3.3-70b-versatile",
  "messages": [
    {
      "role": "user",
      "content": "Hello!"
    }
  ]
}
```

**Response**

```json
{}
```

**SDK Code**

```python
import requests

url = "https://api.respan.ai/api/groq/v1/chat/completions"

payload = {
    "model": "llama-3.3-70b-versatile",
    "messages": [
        {
            "role": "user",
            "content": "Hello!"
        }
    ]
}
headers = {
    "Authorization": "Bearer <respanApiKey>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://api.respan.ai/api/groq/v1/chat/completions';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <respanApiKey>', 'Content-Type': 'application/json'},
  body: '{"model":"llama-3.3-70b-versatile","messages":[{"role":"user","content":"Hello!"}]}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.respan.ai/api/groq/v1/chat/completions"

	payload := strings.NewReader("{\n  \"model\": \"llama-3.3-70b-versatile\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello!\"\n    }\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <respanApiKey>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://api.respan.ai/api/groq/v1/chat/completions")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <respanApiKey>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"llama-3.3-70b-versatile\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello!\"\n    }\n  ]\n}"

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://api.respan.ai/api/groq/v1/chat/completions")
  .header("Authorization", "Bearer <respanApiKey>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"llama-3.3-70b-versatile\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello!\"\n    }\n  ]\n}")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.respan.ai/api/groq/v1/chat/completions', [
  'body' => '{
  "model": "llama-3.3-70b-versatile",
  "messages": [
    {
      "role": "user",
      "content": "Hello!"
    }
  ]
}',
  'headers' => [
    'Authorization' => 'Bearer <respanApiKey>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://api.respan.ai/api/groq/v1/chat/completions");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <respanApiKey>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"model\": \"llama-3.3-70b-versatile\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello!\"\n    }\n  ]\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "Bearer <respanApiKey>",
  "Content-Type": "application/json"
]
let parameters = [
  "model": "llama-3.3-70b-versatile",
  "messages": [
    [
      "role": "user",
      "content": "Hello!"
    ]
  ]
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.respan.ai/api/groq/v1/chat/completions")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```