Create chat completion

curl https://api.lumenfall.ai/openai/v1/chat/completions \
  -H "Authorization: Bearer $LUMENFALL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3-flash-preview",
    "messages": [
      {"role": "user", "content": "Why are capybaras so chill?"}
    ]
  }'

{
  "id": "chatcmpl-abc123",
  "object": "chat.completion",
  "created": 1702345678,
  "model": "google/gemini-3-flash-preview",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Capybaras are remarkably calm animals for several reasons. As the largest rodents in the world, they have few natural predators in their South American habitats, which means they haven't evolved a strong flight-or-fight response. They're also highly social and semi-aquatic, spending much of their time lounging in warm water - which would make anyone relaxed!"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 14,
    "completion_tokens": 71,
    "total_tokens": 85
  }
}

POST

openai

chat

completions

curl https://api.lumenfall.ai/openai/v1/chat/completions \
  -H "Authorization: Bearer $LUMENFALL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3-flash-preview",
    "messages": [
      {"role": "user", "content": "Why are capybaras so chill?"}
    ]
  }'

{
  "id": "chatcmpl-abc123",
  "object": "chat.completion",
  "created": 1702345678,
  "model": "google/gemini-3-flash-preview",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Capybaras are remarkably calm animals for several reasons. As the largest rodents in the world, they have few natural predators in their South American habitats, which means they haven't evolved a strong flight-or-fight response. They're also highly social and semi-aquatic, spending much of their time lounging in warm water - which would make anyone relaxed!"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 14,
    "completion_tokens": 71,
    "total_tokens": 85
  }
}

Modern media applications don’t just generate images and videos — they also make dozens of LLM calls for prompting, captioning, moderation, and orchestration. Instead of juggling a separate provider or router for text, you can use the same Lumenfall SDK, API key, and base URL you already use for media generation. One platform, one bill, no context-switching.

Powered by OpenRouterText completions are routed through OpenRouter, giving you access to all hundreds of models available on their platform — from OpenAI, Google, Anthropic, Meta, Mistral, and many more providers. All OpenRouter features are fully supported. Use any model by passing its OpenRouter model identifier (e.g., google/gemini-3-flash-preview). You can optionally prefix with openrouter/ (e.g., openrouter/google/gemini-3-flash-preview), but it is not required.

OpenAI compatibilityThis endpoint implements the OpenAI Chat Completions API. You can use any OpenAI SDK by changing the base URL to https://api.lumenfall.ai/openai/v1.

Request body

You can include additional parameters not listed here. They will be passed through to the underlying provider.

model

string

required

The model to use. Pass any OpenRouter model identifier — for example, google/gemini-3-flash-preview or openai/gpt-5.4.

messages

array

required

A list of messages comprising the conversation. Each message has a role and content.

Show Message object

role

string

required

The role of the message author. One of system, user, assistant, or tool.

content

string | array | null

required

The content of the message. Can be a string, an array of content parts (for multimodal input), or null (for assistant messages with tool calls).Content parts support text and image_url types:

[
  { "type": "text", "text": "What's in this image?" },
  { "type": "image_url", "image_url": { "url": "https://example.com/image.png" } }
]

name

string

An optional name for the participant.

tool_calls

array

Tool calls generated by the model (assistant messages only).

tool_call_id

string

The ID of the tool call this message is responding to (tool messages only).

stream

boolean

default:"false"

If true, the response is sent as server-sent events (SSE). Partial message deltas are sent as data: {json} lines, ending with data: [DONE].

temperature

number

default:"1"

Sampling temperature between 0 and 2. Higher values make output more random, lower values make it more focused.

max_tokens

integer

The maximum number of tokens to generate.

top_p

number

default:"1"

Nucleus sampling parameter. Only consider tokens with cumulative probability up to this value.

frequency_penalty

number

default:"0"

Penalizes tokens based on their frequency in the text so far. Range: -2.0 to 2.0.

presence_penalty

number

default:"0"

Penalizes tokens based on whether they appear in the text so far. Range: -2.0 to 2.0.

stop

string | array

Up to 4 sequences where the model will stop generating.

tools

array

A list of tools the model may call. Currently only function type tools are supported.

Show Tool object

type

string

required

The type of tool. Currently only function is supported.

function

object

required

name

string

required

The name of the function.

description

string

A description of what the function does.

parameters

object

The parameters the function accepts, described as a JSON Schema object.

tool_choice

string | object

Controls which tool the model calls. Options:

"none" - Do not call any tool
"auto" - Model decides whether to call a tool
"required" - Model must call a tool
{"type": "function", "function": {"name": "my_function"}} - Call a specific function

response_format

object

The format of the response. Set {"type": "json_object"} to enable JSON mode.

seed

integer

A seed for deterministic generation. Not all models support this.

user

string

A unique identifier representing your end-user.

logprobs

boolean

default:"false"

Whether to return log probabilities of the output tokens.

top_logprobs

integer

Number of most likely tokens to return at each position (0-20). Requires logprobs: true.

stream_options

object

Options for streaming responses.

Show Stream options

include_usage

boolean

If true, an additional chunk is sent with usage information when streaming.

Response

string

A unique identifier for the chat completion.

object

string

Always chat.completion.

created

integer

Unix timestamp of when the completion was created.

model

string

The model used for the completion.

choices

array

A list of chat completion choices.

Show Choice object

index

integer

The index of the choice.

message

object

The generated message.

Show Message object

role

string

Always assistant.

content

string | null

The generated text content, or null if the model called a tool.

tool_calls

array

Tool calls made by the model, if any.

finish_reason

string

The reason the model stopped generating. One of stop, length, tool_calls, or content_filter.

usage

object

Token usage statistics for the request.

Show Usage object

prompt_tokens

integer

Number of tokens in the prompt.

completion_tokens

integer

Number of tokens in the generated completion.

total_tokens

integer

Total number of tokens used.

Streaming

When stream: true is set, the response is sent as server-sent events. Each event contains a chat.completion.chunk object with a delta field instead of message:

data: {"id":"chatcmpl-abc123","object":"chat.completion.chunk","created":1702345678,"model":"google/gemini-3-flash-preview","choices":[{"index":0,"delta":{"role":"assistant"},"finish_reason":null}]}

data: {"id":"chatcmpl-abc123","object":"chat.completion.chunk","created":1702345678,"model":"google/gemini-3-flash-preview","choices":[{"index":0,"delta":{"content":"Capybaras"},"finish_reason":null}]}

data: {"id":"chatcmpl-abc123","object":"chat.completion.chunk","created":1702345678,"model":"google/gemini-3-flash-preview","choices":[{"index":0,"delta":{},"finish_reason":"stop"}]}

data: [DONE]

curl https://api.lumenfall.ai/openai/v1/chat/completions \
  -H "Authorization: Bearer $LUMENFALL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3-flash-preview",
    "messages": [
      {"role": "user", "content": "Why are capybaras so chill?"}
    ]
  }'

{
  "id": "chatcmpl-abc123",
  "object": "chat.completion",
  "created": 1702345678,
  "model": "google/gemini-3-flash-preview",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Capybaras are remarkably calm animals for several reasons. As the largest rodents in the world, they have few natural predators in their South American habitats, which means they haven't evolved a strong flight-or-fight response. They're also highly social and semi-aquatic, spending much of their time lounging in warm water - which would make anyone relaxed!"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 14,
    "completion_tokens": 71,
    "total_tokens": 85
  }
}

Cancel video List models

​Request body

​Response

​Streaming

Request body

Response

Streaming