🔌 AI APIs - Developer's Comparison Guide
Every major AI provider offers an API - a way to call AI models programmatically from your own code. This guide compares the top options: pricing, strengths, and when to use each.
🟣
Best for complex tasks
Anthropic API
Claude Opus 5, Sonnet 5, Haiku 4.5 (Fable 5.1 for the hardest agentic work)
Best reasoning and agent tooling, 1M context on Sonnet and up, safest for production
Sonnet: $2/$10 per 1M tokens (in/out)
🟢
Most popular
OpenAI API
GPT-5.6 Sol / Terra / Luna (GPT-6 Astra in limited preview)
Widest ecosystem, best plugin/tool support, most integrations
GPT-5.6 Sol: $5/$30 per 1M tokens
🔵
Best free tier
Google AI (Gemini API)
Gemini 3.1 Pro, Gemini 3.8 Flash
1M context, multimodal, generous free tier, Search grounding
Flash: Free tier + $0.75/$3.75 per 1M
🔴
Best value API
Mistral API
Mistral Large, Medium, Small
Fast, affordable, European (GDPR-friendly), good for coding
Small: $0.20/$0.60 per 1M tokens
⭐
Fastest inference
Groq API
Llama 3.1 70B, Mixtral, Gemma
Extremely fast inference (LPU chips), great for real-time apps
Llama 70B: $0.59/$0.79 per 1M tokens
🤗
Most model variety
Hugging Face Inference API
700K+ open-source models
Access to any open-source model via one API, flexible
Free tier + pay-per-use from $0.06/hr
⚡ Hello World - Your First API Call
Every AI API follows the same pattern: authenticate with an API key, send a message, receive a response. Here is the same call in Python for the three most popular APIs:
Anthropic (Claude)
pip install anthropic
import anthropic
client = anthropic.Anthropic(api_key="sk-ant-...")
message = client.messages.create(
model="claude-sonnet-5",
max_tokens=1024,
messages=[{"role": "user", "content": "Hello!"}]
)
print(message.content[0].text)
OpenAI (GPT)
pip install openai
from openai import OpenAI
client = OpenAI(api_key="sk-...")
response = client.chat.completions.create(
model="gpt-5.6-sol",
messages=[{"role": "user", "content": "Hello!"}]
)
print(response.choices[0].message.content)
Ollama - Local (no API key!)
pip install ollama
import ollama
response = ollama.chat(
model='llama3.1',
messages=[{'role': 'user', 'content': 'Hello!'}]
)
print(response['message']['content'])
💰 Cost Calculator - Rough Guide
APIs charge per token (roughly 1 token ≈ 0.75 words). Here is what typical usage costs:
| Task | Tokens (approx) | Claude Sonnet 5 | GPT-5.6 Sol |
|---|
| Single Q&A | 500 | $0.003 | $0.009 |
| Code review (1 file) | 2,000 | $0.01 | $0.04 |
| Summarize 10-page doc | 5,000 | $0.03 | $0.09 |
| 1,000 Q&As per month | 500,000 | $3.00 | $8.75 |
| Small app (10K API calls) | 5,000,000 | $30.00 | $87.50 |
Prices above are estimates as of September 7, 2026, assuming a 50/50 input/output split. Always check current pricing at each provider's website. API costs are generally very low for individual developers.