Codex CLI is on the rise. Big difference from Github Copilot. ~Summary of AI Coding trends in January 2026 as seen through data~
AI Coding Agent January trends
We have been operating a site called AI Coding.Info since July 2025.
This is a site that observes usage trends related to AI Coding Agents such as Claude Code, Codex CLI, Github Copilot, and Gemini from a fixed point from information in Github repositories. To determine the use of AI Coding Agent, we conduct daily surveys under the following conditions.
- Daily inspection of 9,000 public repositories on Github
- TOP 300 Github stars by programming language
- Researched from 30 types of programming languages
- Targets 16 types of AI Coding Agents
- Only when the rule files used by various AI Coding Agents are in the Github repository, it is determined that AI Coding Agent is being used.
Last month's trends
https://qiita.com/kotauchisunsun/items/b11a628124ad3b4bb157
AI Coding Agent usage rate is 6.3%
AI Coding Agent repository utilization rate was 6.3%, an increase of 1.0 percentage points from 5.3% last time. The upward trend remains unchanged. That's about it. In the November article, we estimated the overall growth rate to be roughly less than 0.73%. Therefore, **1.0% increase in usage rate seems like a fairly large month of increase. **
AI Coding Agent usage rate on 2/1/2026
https://ai-coding.info/ja?date=2026-02-01#daily-summary
AI Coding Agent usage rate on January 1, 2026
https://ai-coding.info/ja?date=2026-01-01#daily-summary
Changes in the number of repositories using AI Coding Agent from 2026/1/1 to 2026/2/1
https://ai-coding.info/ja?since=2026-01-01&until=2026-02-01#time-based-bar-chart
Share of AI Coding Agent by product
The share by product is as follows.
| Ranking | Product name | Share rate |
|---|---|---|
| 1st place | Claude Code | 32.2 % |
| 2nd place | Codex CLI | 28.3 % |
| 3rd place | Copilot Agent | 22.3 % |
| 4th place | Cursor | 9.0 % |
| 5th place | Gemini CLI | 6.0 % |
**Codex CLI has surpassed Github Copilot Agent to take second place in industry share. ** In last month's article, Copilot Agent and Codex CLI were close. As a result, at the beginning of January, there was a competition with Copilot Agent at the top and Codex CLI at the top, but by the end of January, Codex had decisively taken the top share.
AI Coding Agent share rate on 2026/2/1
https://ai-coding.info/ja?date=2026-02-01#daily-summary
AI Coding Agent share rate on January 1, 2026
https://ai-coding.info/ja?date=2026-01-01#daily-summary
I think there is another point worth discussing here, and that is that Claude Code's market share is also increasing. Codex CLI increased by 3.3% compared to last month, while Claude Code increased by 3.2%, almost the same amount. That's what it means. Considering the story in the previous section, the usage rate for the market as a whole has increased by 1%. Even with these new customers, Claude Code and Codex CLI are increasing their market share. It seems possible to think that.
Why is this so? I feel like it's a little difficult to discuss. It's now easier to use. That's simple, but I don't think it's a quantitative indicator.
Looking at the Coding Index of the site ArtificalAnalysis, it is as follows.
Considering this, GPT-5.2 and Claude Opus 4.5 have high performance. Therefore, the market share has increased. I think it's hard to say. The reason is that Github Copilot supports both.
https://docs.github.com/ja/copilot/reference/ai-models/supported-models
And if it is true that if the AI model is smart, the market share will increase,'' then Gemini's market share is so low'' is logically inconsistent.
I don't have a very satisfactory answer regarding this. If you think about it, this is the reason why "Codex CLI" and "Claude Code" have grown. This is because I feel that ``elements other than the intelligence of the AI model'' are becoming important. Isn't that the ability to grasp the project of the product itself, or something like that? I think so, but it's still a hypothesis.
AI Coding Agent usage status by programming language
The programming language in which AI Coding Agent is used most is "TypeScript," the second is "Python," the third is "Rust," the fourth is "Go," and the fifth is "C#." Things have stabilized around here. Kotlin'' has grown a little, and there are some areas where it is close to C#''.
AI Coding Agent ranking by programming language on February 1, 2026
https://ai-coding.info/ja?date=2026-02-01#daily-summary
AI Coding Agent ranking by programming language on January 1, 2026
https://ai-coding.info/ja?date=2026-01-01#daily-summary
Monthly trends in the number of repositories used by AI Coding Agent
As of 2026/02/01, the number of repositories used by AI Coding Agent was 836. On January 1, 2026, there were 703 cases, so this is an increase of 123 cases. As of 2025/12/1, there were 619 cases, and the increase from 2025/12/1 to 2026/1/1 was 84 cases. Considering this, the overall usage rate increased by 1%. That's a pretty amazing number, and I think that's what's influencing the increase in the number of repositories. If you look at it this way, the increase is about 1.5 times, so I think it's spreading rapidly.
Changes in the number of repositories using AI Coding Agent from 2026/1/1 to 2026/2/1
https://ai-coding.info/ja?since=2026-01-01&until=2026-02-01#time-based-bar-chart
Usage trends of TypeScript's AI Coding Agent
Currently, TypeScript is the most advanced programming language in terms of AI usage. It's interesting to look at this data.
**Utilization rate has increased from 16.7% as of June 30, 2025 to 35.7% as of February 1, 2026. **
The trends in the number of repositories are as follows.
The scope of crawling was changed in August 2025. Therefore, it is difficult to compare data from earlier periods. However, the logic has remained largely unchanged since then. If you look at this, you can see that Cursor continues to be used a certain number, but the number of Codex CLI has increased abnormally.
If you display it as a percentage, you can see how Codex CLI has increased. Cursor itself is in a downtrend, but Gemini has always remained constant. You might say that.
https://ai-coding.info/ja/languages/typescript?since=2025-06-30&until=2026-02-03#share-trend
thoughts
Now, due to AI development, junior engineers will be weeded out. We've talked about this for a while, but listening to Opus' stories, it seems like even ordinary engineers are in a difficult situation. That's what I feel.
https://x.com/mizchi/status/2015349902080094453
"Being fast" was one value, but I think we've entered a very difficult time when we consider that AI is running in parallel without eating or drinking. For example, what I was doing around this time last year was publishing something called reclineK.
https://x.com/kotauchisunsun/status/1879198181805948942
This is ReCline's kotauchi ver. There is a Coding Agent called Cline. This is still being developed, but I don't think many people are using it today. At that time, VS Code had a new implementation called Github Copilot API. This allowed unlimited use of AI (which is no longer possible). However, at the time, Cline did not have the ability to use this Github Copilot API. ReCline was created as an OSS version of Cline that implemented the bridge function.
https://github.com/julesmons/recline-legacy
However, ReCline only provides source code and is not distributed in a format (vsix) that can be installed directly as a plugin with VSCode. As a result, it was difficult to implement. So, I created a CI and created a mechanism to automatically release plugins using reclineK.
https://github.com/kotauchisunsun/reclineK
Well, there was a story like that, but since the official Cline now supports the Github Copilot API, this repository has become a relic. That's what the level was like a year ago. It feels like time is passing so quickly that AI Coding has become a reality where we take it for granted.
This time, starting in early January, AI Coding.info has been significantly revised and now has a date specification function.
**You can see all usage trend data for AI Coding Agent from June 30, 2025 to the latest update date. **
So, I wonder how it was in the past. If you think so, please select a date and take a look. I think so. Originally, I wanted to create a viewing function, but there was a lack of data, so the priority was lowered. Also, last month I wrote an article called "Hell's Crawler Operation - From the Cloud to a Home Physical Server. But...".
https://qiita.com/kotauchisunsun/items/a6ad9e7c3f6a7fc3ba1e
It's a long story to talk about, but one is that the build time increases due to the increase in data, and unless this is resolved, we will not be able to develop and release this date-specific viewing function. That's what I felt. So, in the article I wrote earlier, I worked hard to increase the speed. So we finally developed the function and released it.
By the way, you can also check the data regarding share trends from June 30, 2025 to the latest date and time. **
On the one hand, it was a pain every time I created a custom build to write this article.
Additionally, there will be an event called "AI Driven Development [Osaka Branch #9] with X Server Co., Ltd." on February 25th.
https://aid.connpass.com/event/382749/
This is a study session on AI-driven systems, and I will be on stage to speak at this event, so if you are interested in anything, please feel free to come and talk to me.
Past trends
https://qiita.com/kotauchisunsun/items/b11a628124ad3b4bb157
https://qiita.com/kotauchisunsun/items/7b32a5f969a6322d66b4
https://qiita.com/kotauchisunsun/items/e294d2cf419c46c02046
https://qiita.com/kotauchisunsun/items/5e5244fdabf577d7c879