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How a Free AI Model Beat Every Frontier Model I Tried

AI CodingxAIGrokCursorClaudeGPT-5Developer ToolsLLMs

I am an AI coding abuser. I won't deny it. I shell out ~$200/month on Claude, Codex, and Cursor subscriptions every month, and I still burn through my credits faster than the dry Christmas tree my dad threw it in the fireplace (pro tip: don't do that). AI is part of my daily workflow now. All that is to say, that I am accustomed to being out of credits and staring dejectedly at my usage dashboard. But this past week was different, almost all of my coding came from xAI’s free grok-code-fast-1 model, and it completely changed my perspective on “frontier” models.

Despite having plenty of credits left, even now I'm barley using them. Stark contrast to my normal behavior. And when I have been using them lately, I find myself growing increasingly frustrated and impatient. So what changed? Let me explain.

So there I was, just a solo dev with a project far beyond one person’s scope, deep in a full refactor, and out of inference. Naturally, I did what any budget-conscious, AI-abusing developer would do: I turned to free models, specifically grok-code-fast-1.

When grok-code-fast-1 was first released, I was very impressed, but dismissed it as just another mistake prone small model. I put it in the same bucket as Gemini flash, ultra fast and accurate, but not very intelligent. It did show clear signs of strong reasoning however and was clearly in its own category. Its main problem, at least at the time, was that it didn't spend time learning my codebase before generating code, and often lead to full rollbacks. Since then, two important things have changed:

  • The model is updated weekly
  • Cursor added a planning mode

Just in time to save me from the great inference drought (waiting till Tuesday), Cursor released its planning mode. If you’ve used Claude Code, you know how big this is. It not only lets you fine-tune and structure a model’s task, it also spends much more of its inference analyzing your codebase instead of just generating output.

So I pushed forward. I wrote a huge and complex plan that would've take a person 8 weeks, Claude at least a half an hour with dozens confirmations along the way, and created a new branch. Ready and expecting utter failure, I sent it to grok-code-fast-1. What happened next genuinely surprised me.

It’s was shockingly good and roughly 15 times faster than even Sonnet. Every few seconds it generated a complete ~500-line class, perfectly aligned with my stack, and correcting its own mistakes inside the loop. Seriously, I was expecting to sit there for a while and micro manage it, but before I knew it I had to think of something new to work on. What’s even more impressive is its size: it’s a 100-billion-parameter model, compared to GPT-5’s trillions. If you take the time to write a detailed plan, it executes the entire thing in minutes with near-perfect accuracy.

During this time, I grew increasingly impressed with its phenomenal debugging. I honestly believe it’s the best in the world right now. It interacts with my terminal in ways I didn’t know were possible, while other models like Sonnet and GPT-5 often struggle to perform basic commands such as grepping for a keyword. When I run into a particularly difficult bug, I’ll sometimes use grok-code-fast-1 just to see how it diagnoses the issue. Then I’ll copy those commands and give them to a frontier model. There's no denying that larger models have deeper reasoning and a wider corpus, but they get in their own way so often. Too much context is almost as bad as too little context. So after last week, I will be using a mixture of both.

Here’s the workflow that’s been working for me:

  1. I use Cursor Auto Mode to generate an initial plan, since it has the clearest view of my codebase.
  2. I paste that plan into GPT-5 and/or Grok 4 to get a broader, macro-level critique and iterate until I'm happy.
  3. I go back to Cursor and have it double check the new plan against the codebase and fix any incompatibilities.
  4. Once I’m happy with the final plan, I create a new branch and tell grok-code-fast-1 to build it.

All of this, for free.

And that’s the real breakthrough. Because it’s free right now, and will likely remain very affordable once pricing begins, I can experiment aggressively without worrying about burning through credits. It’s democratizing high-end coding assistance for any budget, and it genuinely feels revolutionary.