Chat Completions
Create OpenAI-compatible chat completions through LLM Gateway. Route requests to any supported model across OpenAI, Anthropic, Google, and 20+ providers.
Create a completion for the chat conversation
Authorization
bearerAuth AuthorizationBearer <token>
Bearer token authentication using API keys
In: header
Request Body
application/json
TypeScript Definitions
Use the request body type in TypeScript.
Response Body
curl -X POST "https://api.llmgateway.io/v1/chat/completions" \ -H "Content-Type: application/json" \ -d '{ "model": "gpt-5", "messages": [ { "role": "user" } ] }'{
"id": "string",
"object": "string",
"created": 0,
"model": "string",
"choices": [
{
"index": 0,
"message": {
"role": "string",
"content": "string",
"reasoning": "string",
"tool_calls": [
{
"id": "string",
"type": "function",
"function": {
"name": "string",
"arguments": "string"
}
}
],
"images": [
{
"type": "image_url",
"image_url": {
"url": "string"
}
}
]
},
"finish_reason": "string"
}
],
"usage": {
"prompt_tokens": 0,
"completion_tokens": 0,
"total_tokens": 0,
"reasoning_tokens": 0,
"prompt_tokens_details": {
"cached_tokens": 0,
"cache_write_tokens": 0,
"cache_creation_tokens": 0,
"cache_creation": {
"ephemeral_5m_input_tokens": 0,
"ephemeral_1h_input_tokens": 0
},
"audio_tokens": 0,
"video_tokens": 0
},
"completion_tokens_details": {
"reasoning_tokens": 0,
"image_tokens": 0,
"audio_tokens": 0
},
"cost": 0,
"cost_details": {
"upstream_inference_cost": 0,
"upstream_inference_prompt_cost": 0,
"upstream_inference_completions_cost": 0,
"total_cost": 0,
"input_cost": 0,
"output_cost": 0,
"cached_input_cost": 0,
"cache_write_input_cost": 0,
"request_cost": 0,
"web_search_cost": 0,
"image_input_cost": 0,
"image_output_cost": 0,
"audio_input_cost": 0,
"data_storage_cost": 0
},
"info": "string"
},
"metadata": {
"request_id": "string",
"requested_model": "string",
"requested_provider": "string",
"used_model": "string",
"used_provider": "string",
"used_region": "string",
"underlying_used_model": "string",
"routing": [
{
"provider": "string",
"model": "string",
"region": "string",
"status_code": 0,
"error_type": "string",
"succeeded": true,
"apiKeyHash": "string",
"logId": "string"
}
]
}
}{
"error": {
"message": "string",
"type": "string",
"param": "string",
"code": "string"
}
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