Free AI Models Comparison: OpenRouter vs Together vs Groq

A practical guide to choosing the best free AI API for your project in 2024.

Introduction

With dozens of free AI models available via unified APIs, choosing the right provider saves time and money. This guide compares the three major free-tier providers: OpenRouter, Together.ai, and Groq.

Quick Comparison

Feature	OpenRouter	Together.ai	Groq
Free Models	50+	20+	10+
Rate Limit	20 req/min	60 req/min	30 req/min
Speed	Medium	Medium	Fastest
Model Variety	Best	Good	Limited
API Format	OpenAI-compatible	OpenAI-compatible	OpenAI-compatible

OpenRouter: Maximum Variety

import requests
import os

def openrouter(model: str = "google/gemini-2.0-flash-exp:free"):
    return {
        "url": "https://openrouter.ai/api/v1/chat/completions",
        "headers": {
            "Authorization": f"Bearer {os.getenv('OPENROUTER_API_KEY')}",
            "Content-Type": "application/json"
        },
        "models": {
            "code": "google/gemini-2.0-flash-exp:free",
            "chat": "meta-llama/llama-3.1-8b-instruct:free",
            "fast": "mistralai/mistral-7b-instruct:free",
            "reasoning": "deepseek/deepseek-r1:free"
        }
    }

Best for: Projects needing model variety, easy model switching

Together.ai: Balanced Performance

import requests
import os

def together(model: str = "meta-llama/Meta-Llama-3.1-8B-Instruct-Turbo"):
    return {
        "url": "https://api.together.xyz/v1/chat/completions",
        "headers": {
            "Authorization": f"Bearer {os.getenv('TOGETHER_API_KEY')}",
            "Content-Type": "application/json"
        },
        "models": {
            "general": "meta-llama/Meta-Llama-3.1-8B-Instruct-Turbo",
            "code": "codellama/CodeLlama-7b-Instruct-hf",
            "chat": "mistralai/Mistral-7B-Instruct-v0.3"
        }
    }

Best for: Consistent performance, good open-source model selection

Groq: Maximum Speed

import requests
import os

def groq(model: str = "llama-3.1-8b-instant"):
    return {
        "url": "https://api.groq.com/openai/v1/chat/completions",
        "headers": {
            "Authorization": f"Bearer {os.getenv('GROQ_API_KEY')}",
            "Content-Type": "application/json"
        },
        "models": {
            "fast": "llama-3.1-8b-instant",
            "large": "llama-3.1-70b-versatile",
            "mixtral": "mixtral-8x7b-32768"
        }
    }

Best for: Low-latency applications, real-time chat

Unified Client Pattern

import requests
import os
from typing import Optional

class FreeAIClient:
    def __init__(self):
        self.providers = {
            "openrouter": {
                "url": "https://openrouter.ai/api/v1/chat/completions",
                "key": os.getenv("OPENROUTER_API_KEY"),
                "default_model": "google/gemini-2.0-flash-exp:free"
            },
            "together": {
                "url": "https://api.together.xyz/v1/chat/completions",
                "key": os.getenv("TOGETHER_API_KEY"),
                "default_model": "meta-llama/Meta-Llama-3.1-8B-Instruct-Turbo"
            },
            "groq": {
                "url": "https://api.groq.com/openai/v1/chat/completions",
                "key": os.getenv("GROQ_API_KEY"),
                "default_model": "llama-3.1-8b-instant"
            }
        }

    def chat(self, prompt: str, provider: str = "openrouter", 
             model: Optional[str] = None, **kwargs) -> str:
        p = self.providers[provider]
        if not p["key"]:
            raise ValueError(f"No API key for {provider}")

        response = requests.post(
            p["url"],
            headers={
                "Authorization": f"Bearer {p['key']}",
                "Content-Type": "application/json"
            },
            json={
                "model": model or p["default_model"],
                "messages": [{"role": "user", "content": prompt}],
                "temperature": 0.7,
                "max_tokens": 500,
                **kwargs
            },
            timeout=30
        )
        response.raise_for_status()
        return response.json()["choices"][0]["message"]["content"]

    def with_fallback(self, prompt: str, providers: list = None) -> str:
        """Try providers in order until one succeeds."""
        providers = providers or ["groq", "together", "openrouter"]
        for provider in providers:
            try:
                return self.chat(prompt, provider)
            except Exception as e:
                print(f"{provider} failed: {e}")
        raise Exception("All providers failed")

# Usage
client = FreeAIClient()
print(client.chat("Hello!", "openrouter"))
print(client.with_fallback("Hello!"))

Rate Limit Handling

import time
import requests
from functools import wraps

def rate_limited(max_per_minute: int):
    min_interval = 60.0 / max_per_minute
    last_call = [0.0]

    def decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            elapsed = time.time() - last_call[0]
            if elapsed < min_interval:
                time.sleep(min_interval - elapsed)
            last_call[0] = time.time()
            return func(*args, **kwargs)
        return wrapper
    return decorator

@rate_limited(20)  # OpenRouter limit
def openrouter_call(prompt: str) -> str:
    # ... implementation
    pass

Recommendation by Use Case

Use Case	Recommended Provider	Model
Code generation	OpenRouter	google/gemini-2.0-flash-exp:free
Chat bot	Groq	llama-3.1-8b-instant
Creative writing	Together.ai	mistralai/Mistral-7B-Instruct-v0.3
Reasoning tasks	OpenRouter	deepseek/deepseek-r1:free
High volume	Together.ai	meta-llama/Meta-Llama-3.1-8B-Instruct-Turbo
Low latency	Groq	llama-3.1-8b-instant
Model experimentation	OpenRouter	Any

Getting Started Checklist

• [ ] Get free API keys from all three providers
• [ ] Store in .env file (never commit!)
• [ ] Test each with a simple prompt
• [ ] Implement fallback logic
• [ ] Add rate limiting
• [ ] Monitor usage in provider dashboards

Conclusion

Start with OpenRouter for maximum flexibility — one key gives access to 50+ models. Add Groq for speed-critical paths and Together.ai for volume. The unified client pattern above makes switching trivial.

All three offer generous free tiers sufficient for development and small production workloads.

---

Part of the Free AI APIs series on Dev.to