Choose Your AI Brain: A Complete Comparison of 4 LLM Options
OpenClaw needs an LLM to work. Understand the differences between ChatGPT subscriptions, OpenRouter, and various APIs to pick the best option for you.
卡住很正常——點段落旁的 😵 卡關 讓我們知道，或直接往下滾到問答區發問。
也可以用 👍 看懂 / 😢 看不懂 告訴我們哪裡寫得好、哪裡要改。
First, Let’s Clear Something Up: OpenClaw ≠ AI
This LaunchDock tutorial helps you understand LLM options — after installing OpenClaw, the next step is picking a brain for it.
Many beginners think that once they install OpenClaw, they can start chatting with AI. Not quite.
OpenClaw is a framework — it helps you manage tools, automate workflows, and connect services. But it doesn’t “think” on its own.
You need to connect it to a “brain,” and that brain is an LLM (Large Language Model).
🧠 Simple analogy: OpenClaw is a car; the LLM is the engine. Without an engine, the car can’t move.
What Is an LLM?
An LLM is the core technology behind ChatGPT, Claude, and Gemini. It has been trained on massive amounts of text data and learned to understand and generate language.
The services you’ve been using are all powered by different companies’ LLMs:
| Service you’ve used | Underlying LLM | Developer |
|---|---|---|
| ChatGPT | GPT-4o, GPT-4o mini | OpenAI |
| Claude | Claude Opus, Sonnet, Haiku | Anthropic |
| Gemini | Gemini 2.0 Flash, Gemini Pro |
OpenClaw can connect to any of these LLMs. And you can switch anytime.
Complete Comparison of 4 Options
Overview
| Option | Monthly Cost | Billing | Difficulty | Best For |
|---|---|---|---|---|
| A. Google AI Studio | Free to start | Pay-per-use | ⭐ Easy | 🏆 Best for beginners |
| B. OpenRouter | Free to start | Pay-per-use | ⭐ Easy | People who want to try multiple models |
| C. OpenAI API | Pay-per-use | Pay-per-use | ⭐⭐ Medium | People who mainly use GPT |
| D. Anthropic API | Pay-per-use | Pay-per-use | ⭐⭐ Medium | People who want the best quality |
Option A: Google AI Studio (Gemini API) 🏆 Recommended for Beginners
| Item | Details |
|---|---|
| Cost | Very generous free tier (15 requests per minute), charges only after exceeding |
| Credit card required | ❌ No |
| Supported models | Gemini 2.0 Flash (fast and cheap), Gemini Pro (more powerful) |
| Key format | Starts with AIzaSy... |
Why is it recommended for beginners?
- Free tier is enough for several weeks of use
- No credit card required — no risk of surprise bills
- Gemini Flash is fast with good quality
- Easiest application process (done in 3 minutes)
Note: This is NOT the same as Google Cloud Console API!
🚨 Common confusion: Google AI Studio is for using Gemini models (i.e., getting an AI brain). Google Cloud Console API is for connecting Google Drive, Gmail, and similar services. They’re completely different, with different application processes.
- Gemini AI brain → Apply at Google AI Studio → This article teaches you how
- Connect Google Drive/Gmail → Apply at Google Cloud Console → See Google API Key Guide
Option B: OpenRouter
| Item | Details |
|---|---|
| Cost | Small free credit on signup, then pay-per-use |
| Credit card required | Not for free tier; required to add funds |
| Supported models | GPT-4o, Claude Sonnet, Gemini, Llama… all of them |
| Key format | Starts with sk-or-... |
Pros: One key gives you access to dozens of models. Want to try Claude? Just change the model name. No need to register separately with each provider.
Best for: People who want to experiment with different models, or don’t want to manage multiple keys.
Option C: OpenAI API
| Item | Details |
|---|---|
| Cost | Pay-per-use, minimum top-up $5 USD |
| Credit card required | ✅ Yes |
| Supported models | GPT-5-mini, 5.3-Codex |
| Key format | Starts with sk-... |
Pros: The GPT ecosystem is the most mature, with the most examples available online.
Note: The API and ChatGPT Plus subscription are billed separately. Having ChatGPT Plus doesn’t mean you have API credits.
Option D: Anthropic API
| Item | Details |
|---|---|
| Cost | $5 free credit on first signup |
| Credit card required | Not for free tier; required afterwards |
| Supported models | Claude Opus, Sonnet, Haiku |
| Key format | Starts with sk-ant-... |
Pros: Claude excels at long-form comprehension, writing quality, and code. Many developers consider Opus to be the strongest all-around model available.
Best for: People who want the best response quality, or who need help with coding.
How Does Pricing Actually Work?
All API plans are billed by Tokens. A Token is the smallest unit of text that AI processes:
- English: roughly 4 characters = 1 Token
- Chinese: roughly 1 character = 1–2 Tokens
Real-World Cost Reference
| Use Case | Approx. Tokens | Gemini Flash Cost | Claude Opus Cost |
|---|---|---|---|
| Ask a simple question | ~500 | < $0.001 | ~$0.02 |
| Organize a page of notes | ~2,000 | < $0.001 | ~$0.08 |
| Write a full report | ~5,000 | < $0.001 | ~$0.20 |
| Normal daily usage | ~20,000 | ~$0.003 | ~$0.80 |
| Normal monthly usage | ~600,000 | ~$0.10 | ~$24.00 |
For a deep dive, check out Token Economics.
How to Avoid Bill Shock?
You won’t. Every provider lets you set a spending limit:
- OpenAI: Settings → Billing → Usage limits → Set a Hard cap
- Anthropic: Settings → Plans & Billing → Usage limit
- Google AI Studio: The free tier has built-in limits and won’t auto-charge
Once you hit the limit, it automatically stops — no further charges.
So Many Models — How to Choose?
For beginners, just remember this quick reference:
| Your Need | Recommended Model | Reason |
|---|---|---|
| Just trying it out, don’t want to spend money | Gemini 2.0 Flash | Largest free tier |
| Daily Q&A, simple tasks | GPT-4o mini / Gemini Flash | Cheap and fast |
| Writing reports, analysis, coding | Claude Sonnet / GPT-4o | Best quality |
| Processing very long documents | Gemini 1.5 Pro | ~1 million Token context window |
Make Your Choice
By now, you should have a plan in mind. If you’re still unsure:
- Complete beginner, don’t want to spend money → Choose A. Google AI Studio
- Want to try different things → Choose B. OpenRouter
- Already have a preferred model → Choose C or D
Made your decision? Next step — let’s go get your API Key 👉 Apply for an API Key
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