Migrating from Grok 3 to Grok 4: A Developer's Guide
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Zack Saadioui
8/14/2025
So, you’ve been working with Grok 3, and now the shiny new Grok 4 is here. The buzz is real, & for good reason. Elon Musk & the xAI team have been busy, & Grok 4 is a MONSTER of an upgrade. But with great power comes… well, the need to figure out how to actually use the thing without breaking all your existing projects.
If you're wondering how to make the jump from Grok 3 to Grok 4 without pulling your hair out, you've come to the right place. I've been digging through the docs, playing with the API, & figuring out all the little details so you don't have to. Think of this as your friendly, no-nonsense guide to a seamless transition. We'll cover everything from the cool new features that will make you want to upgrade yesterday, to the nitty-gritty technical details for a smooth migration.
Honestly, it’s a pretty exciting time in the world of AI, so let's get into it.
What's the Big Deal with Grok 4 Anyway?
First off, let's talk about why you should even bother upgrading. Grok 4 isn't just a minor update; it's a fundamental leap forward. xAI has thrown a TON of resources at this, & it shows. They used their massive 200,000 GPU cluster, "Colossus," to train Grok 4, which is a massive step up in terms of computing power. This has resulted in some seriously impressive capabilities.
Here’s a quick rundown of the head-turning new features:
Always-On Reasoning for Deeper Thinking
Remember how in Grok 3 you could toggle the "reasoning mode"? Well, in Grok 4, that's a thing of the past. It's always in reasoning mode. This means it doesn't just spit out the first thing that comes to its digital mind. Instead, it takes a "first-principles" approach, breaking down problems & thinking them through before giving you an answer. This leads to more accurate, reliable, & well-thought-out responses, which is a HUGE plus for complex tasks.
It's Got Eyes! Multimodality is Here
This is a big one. Grok 4 is now multimodal, meaning it can understand more than just text. Right now, it can process images, with voice & video capabilities on the horizon. You can literally show it a picture & ask questions about it. This opens up a whole new world of possibilities, from analyzing charts & diagrams to getting help with visual-based coding problems.
A HUGE Memory Upgrade: The 256k Context Window
If you've ever felt limited by the context window of previous models, you're going to love this. Grok 4 boasts a massive 256,000-token context window. That's double Grok 3's 131,072 tokens. This means you can feed it much larger documents, have longer & more coherent conversations, & it will remember what you were talking about from the beginning. It's a game-changer for tasks that require a lot of context, like summarizing a book or analyzing a large codebase.
Grok 4 Heavy: The "Multi-Agent" Powerhouse
For those who need even more power, there's Grok 4 Heavy. This premium version uses a multi-agent system where several AI agents work together in parallel to tackle a problem. This not only improves accuracy but also helps to reduce hallucinations. It's designed for the most demanding tasks in research, coding, & analysis.
Native Tool Use & Real-Time Web Access
Grok 4 comes with "native tool use," which means it can use tools like a code interpreter & web browser to help it solve problems. Its "DeepSearch" feature allows it to access real-time information from the web & X (formerly Twitter), so you're not limited to the static data it was trained on. This is HUGE for getting up-to-the-minute information on just about anything.
A Dedicated Coding Companion: Grok 4 Code
Developers, rejoice! There’s a specialized version called Grok 4 Code. It’s built specifically for programming tasks & has shown some impressive performance on benchmarks like SWE-Bench. It can help you write clean code, find bugs, & even integrate with your existing development tools.
The Developer's Guide to a Seamless Transition
Alright, now for the part you've probably been waiting for: how to actually migrate your projects from Grok 3 to Grok 4 without causing a digital meltdown. The good news is, it's not as scary as it sounds. But there are some key changes you NEED to be aware of.
The Breaking Changes: What to Watch Out For
Let's get the "uh-oh" stuff out of the way first. There are a few parameters from the Grok 3 API that are no longer supported in Grok 4. If you try to use them, you'll get an error. So, the first thing you need to do is a find-and-replace in your code to get rid of them.
Here are the deprecated parameters:
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presencePenalty
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frequencyPenalty
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stop
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reasoning_effort
These parameters are no longer needed because of Grok 4's new architecture. As we mentioned, it's always in reasoning mode, so there's no need to toggle it. The other parameters have also been made redundant by the new model's improved capabilities.
Updating Your API Calls: The Nitty-Gritty
Now, let's get into the code. The core of the transition involves updating how you make your API calls.
The New API Endpoint
The first thing you'll need to do is change the base URL for your API requests. The new endpoint for Grok 4 is:
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https://api.x.ai/v1
The New Python SDK
xAI has released a new Python SDK to make interacting with the Grok 4 API easier. You can install it via pip: