The use of AI Coding is accelerating unpredictably - Summary of AI Coding trends in April 2026 based on data -
AI Coding Agent trends in April 2026
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/ab78bb338500b4c71103
AI Coding Agent usage rate is 10.0%
AI Coding Agent repository utilization rate is 10.0%, an increase of 1.3% from 8.7% last time. **Usage rate has increased by 1% since January 2026. Penetration is progressing at an astonishing rate. ** [As of December 2025] (https://qiita.com/kotauchisunsun/items/b11a628124ad3b4bb157), the monthly usage rate increase was still 0.5%, but since then, the usage rate has always increased by more than 1%.
AI Coding Agent usage rate on May 1, 2026
https://ai-coding.info/ja?date=2026-05-01#adoption-rate
AI Coding Agent usage rate on April 1, 2026
https://ai-coding.info/ja?date=2026-04-01#adoption-rate
Trends in AI Coding Agent usage rate from April 1, 2026 to May 1, 2026
https://ai-coding.info/ja?date=2026-04-01&since=2026-04-01&until=2026-05-01#share-trend
Share of AI Coding Agent by product
The share by product is as follows.
| Ranking | Product name | Share rate |
|---|---|---|
| 1st place | Codex CLI | 35.1% |
| 2nd place | Claude Code | 32.8% |
| 3rd place | Copilot Agent | 18.0% |
| 4th place | Gemini CLI | 5.8% |
| 5th place | Cursor | 5.8% |
I wonder if the overall atmosphere has changed. That's the impression. This month too, Codex is in first place, Claude Code is in second place, and Copilot is in third place, making stable movements. However, there seems to be a convergence with these three products, or with the top two products; as of March 2026, the usage rate of Cursor was 11.0% and Gemini was 6.6%. This month, Gemini and Cursor have swapped places, and for the first time, Gemini is now in 4th place. However, this is also difficult, and if anything, the usage rate of Cursor is gradually decreasing, while Gemini is doing well. That view may be more correct. Copilot is also in 3rd place, but considering that it had a 19.0% share last month, it has either decreased slightly or stayed the same. Is that the form?
AI Coding Agent share rate on 5/1/2026
https://ai-coding.info/ja?date=2026-05-01&since=2026-04-01&until=2026-05-01#agent-share
AI Coding Agent share rate on April 1, 2026
https://ai-coding.info/ja?date=2026-04-01&since=2026-04-01&until=2026-05-01#agent-share
AI Coding Agent usage status by programming language
The programming language in which AI Coding Agent is used the most is "TypeScript," the second is "Python," the third is "Rust," the fourth is "Go," and the fifth is "C#." Previously, Python had a stable position in second place. However, since February of this year, the difference between Go and Rust has become less and less. So this time around, Python happens to be back in second place. That's the impression I get. As a result, "Python," "Rust," and "Go" continue to compete in terms of the number of AI Coding Agents used. That's the impression I get.
AI Coding Agent ranking by programming language on May 1, 2026
https://ai-coding.info/ja?date=2026-05-01&since=2026-04-01&until=2026-05-01#language-agent-rank
AI Coding Agent ranking by programming language on April 1, 2026
https://ai-coding.info/ja?date=2026-05-01&since=2026-04-01&until=2026-05-01#language-agent-rank
Monthly trends in the number of repositories used by AI Coding Agent
The number of repositories was 1,234 as of 2026/04/01, but has increased to 1,436 as of 2026/05/01, and the number of repositories using AI Coding Agent has increased by 202. Considering that there was an increase of 154 cases last month, you can see that the number of users is increasing even more.
Changes in the number of repositories using AI Coding Agent from April 1, 2026 to May 1, 2026
https://ai-coding.info/ja?date=2026-04-01&since=2026-04-01&until=2026-05-01#time-based-bar-chart
Strong deviation from long-term forecast
The article was published on December 31, 2025.
https://qiita.com/kotauchisunsun/items/b11a628124ad3b4bb157
At this time, we fitted the data from July 1, 2025 to December 31, 2025 to predict the usage rate of AI Coding Agent in 2026. At that time, the results were as follows. We defined the function as below and performed fitting to the usage rate of the entire AI Coding Agent.
The result is as below.
K = 7.7575e-02
A = 2.8346e+00
B = 9.6907e-03
t0 = -4.4439e+00
決定係数 (R^2) = 0.9852
σ: 0.0012
If we draw a forecast line until the end of 2026, it will look like this:
at that time,
**AI Coding Agent usage rate across programming languages at the end of 2026 is expected to be between 7.29% and 8.01%. **
I concluded. However, **The usage rate of AI Coding Agent this month was 10.0%. It's completely unexpected. ** From here,
**A structural change in the use of AI Coding Agents occurred in 2026. **
You might say that. This is difficult to answer, but I think there are two main points at issue. The first point is that the prediction formula is wrong in the first place. At the end of the year, we performed fitting using a logistic curve. However, this may be wrong in the first place. That is undeniable. However, since the coefficient of determination was 0.98, we believe that the model was not that bad at the time of prediction. (Also, there is the problem that such long-term predictions are inherently difficult.) I wrote about this in an article in March, but for a certain period of time, the usage rate of AI Coding Agent in specific languages was rapidly increasing.
https://qiita.com/kotauchisunsun/items/ab78bb338500b4c71103
This March article suggests that the release of Codex may be the culprit. I concluded. Going back to the December article, at that time we also performed fitting of usage rates for multiple programming languages. Compare this value with the current usage rate.
| Language | Upper limit predicted usage rate (K) | Usage rate (as of 5/1) |
|---|---|---|
| TypeScript | 100.0% | 46.0% |
| Python | 100.0% | 23.0% |
| Rust | 13.4% | 27.3% |
| Go | 12.4% | 25.4% |
| C# | 12.3% | 20.2% |
It was expected that TypeScript and Python would have a usage rate of 100% at the extreme. However, for Rust, even the predicted upper limit was 13.4%. However, Rust's usage rate has more than doubled to 27.3% as of May 1st. Current usage rates for other languages are observed to be approximately double the upper limit. In the March article, the languages likely to be affected by the release of Codex were Go, C++, and Rust, and as a result, there was a large fluctuation in the usage rate of AI. I concluded. The period of change was around February 16, 2026. The original forecast only had data up to December 31, 2025, so such a sudden rise in usage rates could not have been predicted. It is possible. Therefore, ``it is correct not to get it right'', but I don't think you will be convinced. Regarding TypeScript and Python, I think December's predictions were relatively accurate. That's what I think.
As you can see by reading the graph, the usage rate of AI Coding Agent in TypeScript is around 37-42% as of April 18th. As for Python, it's around 16% to 24%. Considering that, the value as of May 1st is not that far off. I have a feeling that. There is an explanation for this, and it can be said that ``In the first place, the use of AI Coding was very advanced in TypeScript and Python.'' Therefore, even with the release of Codex, replacements may have progressed, but it did not have a major impact on the usage rate. You might say that. In fact, "languages with little use of AI Coding," such as Rust and Go, are making an impact in this year's releases, and are the main reason why predictions are off. You can think about it.
thoughts
We report on trends in the usage rate of AI Coding Agent every month, but the discrepancy from what we predicted at the end of last year has become large. That's what I felt. As of last month, the overall usage rate started to exceed 8%, so I think I need to change my mind. Therefore, it was time to look back and explore the cause. As a result of looking back, I realized that it is difficult to predict the future. That's what I thought, but when it came to TypeScript and Python, I was able to make predictions more accurately than I expected. That was a surprise. This time, I didn't have time to do the fitting, so I didn't re-predict, but I wonder if AI Coding.Info can provide a predicted usage rate like this as one of its functions. I thought about it for a while. Also, recent topics include the announcement of Claude Mythos and GPT 5.5.
https://forbesjapan.com/articles/detail/95537
https://openai.com/ja-JP/index/introducing-gpt-5-5/
As for Mythos, it was stopped from being published because it was too clever and dangerous. There were also stories like this. Now, Codex has become the number one market share. This is AI Coding.Info's opinion, but it seems necessary to pay attention to how Claude's movements will affect future market share.