What LLM models are available through the ModelsLab Chatbot API?

ModelsLab provides access to Llama 3.1 (8B, 70B, 405B), Mistral, DeepSeek R1, DeepSeek V3, Qwen 2.5 (7B, 32B, 72B), and dozens of other open-source and fine-tuned LLM models. You can switch between models by changing the model_id parameter in your API request.

Is the API compatible with OpenAI format?

Yes, the ModelsLab Chatbot API follows the OpenAI chat completions format. Existing code built for OpenAI can migrate by changing the base URL and API key. This includes streaming, function calling, JSON mode, and conversation history management.

Does the API support streaming responses?

Yes, the API supports real-time streaming via server-sent events (SSE). Set stream: true in your request to receive token-by-token responses, reducing perceived latency for chat applications.

What is the response latency?

First-token latency is typically under 1 second for most models. Total generation time depends on the model size and max_tokens parameter. Streaming mode delivers tokens in real-time as they are generated.

Imagen

Chatbot API - Build AI Chatbots with LLMs

Name: Chatbot API
Brand: ModelsLab
Rating: 4.6 (7 reviews)

Build intelligent chatbots with ModelsLab's chatbot API. Access powerful LLM models to create conversational AI experiences for customer support, content generation, and more.

Build Your Chatbot Now API Documentation

What Is the ModelsLab Chatbot API?

A Unified API for Conversational AI

The ModelsLab Chatbot API provides developers with a single REST endpoint to access multiple large language models including Llama 3.1, Mistral, DeepSeek R1, Qwen, and specialized fine-tuned variants. Instead of managing separate integrations for each model provider, you send requests to one API and switch models by changing a single parameter — the model_id.

The API follows an OpenAI-compatible chat completions format, which means existing codebases built for OpenAI can migrate to ModelsLab by changing the base URL and API key. This compatibility extends to streaming responses via server-sent events, function calling, JSON mode for structured output, and conversation history management.

Access Llama, Mistral, DeepSeek, Qwen, and other open-source LLMs through one endpoint
OpenAI-compatible format — migrate existing code by changing base URL
Streaming responses with server-sent events for real-time chat UX
Function calling and JSON mode for structured data extraction
System prompts for chatbot personality and behavior control
Pay-per-token pricing starting at $1.50 per million tokens

How Does ModelsLab Compare to Other Chatbot APIs?

ModelsLab differentiates from direct model providers (OpenAI, Anthropic) by offering access to open-source models without infrastructure management. Compared to platforms like Together AI and Groq, ModelsLab provides a broader model catalog including image, video, and audio models alongside LLMs — enabling multimodal chatbot experiences through a single API key.

Pricing is competitive: DeepSeek R1 costs $2.40 per million tokens on ModelsLab, Qwen models range from $2.00 to $3.60 per million tokens, and Llama models start at $1.50 per million tokens. There are no minimum commitments — you pay only for tokens consumed.

When Should You Use This API?

The ModelsLab Chatbot API is designed for developers building conversational features into applications — customer support bots, AI assistants, content generation tools, and interactive tutoring systems. It is particularly suited for teams that need access to multiple LLM options without locking into a single provider, or teams building multimodal AI products that combine chat with image generation or voice synthesis.

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Available AI APIs

How Do You Send a Chat Request?

Build a working chatbot in minutes with these code examples. The API follows an OpenAI-compatible format for easy migration.

cURL — Chat Completion

bash

1curl -X POST https://modelslab.com/api/v6/llm/chat \
2  -H "Content-Type: application/json" \
3  -d '{
4    "key": "your_api_key",
5    "model_id": "deepseek-r1",
6    "messages": [
7      {"role": "system", "content": "You are a helpful assistant."},
8      {"role": "user", "content": "Explain how transformers work in 3 sentences."}
9    ],
10    "max_tokens": 512,
11    "temperature": 0.7
12  }'

Python — Streaming Chat

python

1import requests
2
3response = requests.post(
4    "https://modelslab.com/api/v6/llm/chat",
5    json={
6        "key": "your_api_key",
7        "model_id": "llama-3.1-70b",
8        "messages": [
9            {"role": "system", "content": "You are a customer support agent."},
10            {"role": "user", "content": "How do I reset my password?"}
11        ],
12        "stream": True,
13        "max_tokens": 1024
14    },
15    stream=True
16)
17
18for line in response.iter_lines():
19    if line:
20        print(line.decode("utf-8"))

JavaScript — Function Calling

javascript

1const response = await fetch("https://modelslab.com/api/v6/llm/chat", {
2  method: "POST",
3  headers: { "Content-Type": "application/json" },
4  body: JSON.stringify({
5    key: "your_api_key",
6    model_id: "qwen-2.5-72b",
7    messages: [
8      { role: "user", content: "What's the weather in San Francisco?" }
9    ],
10    tools: [{
11      type: "function",
12      function: {
13        name: "get_weather",
14        description: "Get current weather for a location",
15        parameters: {
16          type: "object",
17          properties: {
18            location: { type: "string", description: "City name" }
19          },
20          required: ["location"]
21        }
22      }
23    }]
24  })
25});
26
27const data = await response.json();
28console.log(data);

What LLM Models Can You Access?

Access multiple LLM models through a single API endpoint. Deploy chatbots with streaming responses, context management, and custom system prompts.

Multiple LLM Models

Choose from a range of open-source large language models including Llama 3.1, Mistral, DeepSeek R1, and specialized fine-tuned variants. Switch models with a single parameter change — no infrastructure changes needed.

Streaming Responses

Deliver real-time, token-by-token responses to your users with server-sent events. Reduce perceived latency and create responsive chat experiences that feel natural.

Custom System Prompts

Define your chatbot personality, tone, and behavior with system prompts. Create specialized assistants for customer support, sales, onboarding, or any domain-specific use case.

Chat Options

Access models without content restrictions for creative writing, roleplay, fiction, and research applications. Full control over content filtering at the API level.

Everything you need to build production-ready chatbots and conversational AI applications.

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How to Build a Chatbot with Our API

Deploy your first AI chatbot in minutes, not weeks.

STEP 01

Step 1: Get Your API Key

Create a free account on ModelsLab and generate your chatbot API key from the dashboard. Start with the free tier — no credit card required.

STEP 02

Step 2: Configure Your Chatbot

Choose your LLM model, set a system prompt to define your chatbot personality, and configure parameters like temperature, max tokens, and response format.

STEP 03