The State of C 2025
This report on the state of C development is based on data from the JetBrains Developer Ecosystem Survey 2025, which gathered responses from almost 900 C developers from 23 countries.
We asked professional and student developers about the tools, standards, and practices they use when working with C, including their preferred compilers, IDEs, testing frameworks, and build systems. We also explored how C developers use AI-powered tools, the benefits they gain, and their concerns about AI adoption.
From embedded systems and legacy modernization to high-performance applications, C continues to shape the software world. This report offers a snapshot of the current C landscape and a look at where the language and its community are heading next.
Which C standard(s) do you regularly use?
| 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | |
|---|---|---|---|---|---|---|---|
| – | – | – | – | 4% | 6% | 17% | C23 |
| – | – | 9% | 17% | 20% | 20% | 21% | C17/C18 |
| 51% | 52% | 46% | 44% | 45% | 42% | 42% | C99 |
| 39% | 43% | 37% | 33% | 33% | 32% | 36% | C11 |
| 21% | 21% | 17% | 15% | 18% | 23% | 21% | Embedded C |
| – | – | 18% | 17% | 17% | 16% | 16% | I'm not sure |
| 2% | 2% | 3% | 2% | 2% | 1% | 1% | Other |
C99 remains the most common standard (42%), followed by C11 (36%), Embedded C (21%), and C17/C18 (21%). C23 adoption has increased from a modest 4% at release to 17% this year, showing steady growth.
Which IDE or editor do you use the most for C development?
Note: Despite all the measures we've taken to secure a representative pool of respondents, the results may be slightly skewed toward users of JetBrains products, as they may have been more likely to participate in the survey.
Which unit testing frameworks do you regularly use?
About one-third of C developers don’t write tests, and one in five tests without frameworks. GoogleTest (13%) is the most popular framework, followed by CUnit (7%).
Which project models or build systems do you regularly use?
CMake adoption keeps climbing, with 56% of developers now using it. Makefiles remain in second place at 37%, followed by Visual Studio projects at 29%.
Which dependency manager(s) do you use in your projects?
Half of C developers don’t use a dependency manager. Among those who do, system package managers are most common (28%), with vcpkg (9%), Conan (6%), and NuGet (6%) trailing behind.
Which compilers do you regularly use?
GCC dominates with 82%, followed by Clang (44%) and MSVC (21%). Embedded compilers like Keil and IAR are niche but present.
Which standards or guidelines do you follow when coding in C?
22%
24%
ClangFormat
21%
25%
Clang-Tidy
11%
9%
ISO/IEC 27001
10%
9%
MISRA C
6%
8%
AUTOSAR
5%
3%
SEI CERT C
2%
2%
Other
44%
45%
None
44% of C developers surveyed don’t follow any formal guidelines. ClangFormat and Clang-Tidy are each used by about 21%–22% of C developers, with MISRA C and AUTOSAR at 10% and 6% respectively.
How likely are you to try AI coding agents in the next 12 months?
40%
50%
Very likely
22%
21%
Somewhat likely
12%
10%
Not sure
6%
4%
Somewhat unlikely
9%
6%
Very unlikely
11%
10%
I already use AI coding agents
In your opinion, how likely is your company to try AI coding agents in the next 12 months?
35%
44%
Very likely
25%
21%
Somewhat likely
18%
15%
Not sure
10%
5%
Somewhat unlikely
7%
5%
Very unlikely
6%
10%
My company is already using AI coding agents
In your opinion, why would your company not be likely to try AI coding agents in the next 12 months?
50%
52%
Data privacy and security concerns
44%
30%
Concerns about intellectual property rights over code generated by such tools
26%
18%
Processes and decision-making for adopting new technologies are slow and conservative
21%
19%
Difficulty in incorporating such tools into existing workflows and systems
19%
18%
Lack of knowledge about such tools in the company
19%
13%
Distrust of new technologies
18%
14%
Coders don’t see value in such tools or services
40% of C developers are very likely to try AI coding tools in the next year, compared to 50% of developers who use other languages. Just 11% of C developers are already using AI, with security and IP concerns cited as the main blockers to adoption, followed by slow internal processes and lack of awareness.
Which types of AI- or LLM-powered tools or services are used in your organization?
37%
55%
Third-party cloud-based AI tools or services
22%
16%
Organization’s own local, non-cloud-based AI tools or services
21%
19%
Organization’s own cloud-based AI tools or services
17%
13%
Third-party cloud-based AI tools or services managed and hosted by my company
17%
11%
Third-party locally installed, non-cloud-based AI tools or services
9%
9%
I don’t know
1%
1%
Other
14%
11%
None
Among C developers, cloud-based third-party AI tools lead with 37% usage. Local or organization-hosted solutions rank second, with 22% adoption.
7%
8%
Less than 1 hour
17%
21%
From 1 to less than 2 hours
34%
29%
From 2 to less than 4 hours
18%
20%
From 4 to less than 8 hours
20%
18%
8 hours or more
5%
4%
I don’t save any time
Most C developers report saving 2–4 hours weekly thanks to AI tools.
What is your biggest concern about AI in coding and software development?
27%
23%
Quality of generated code
15%
11%
Negative effect on my coding and development skills
15%
19%
Limited understanding of complex code and logic by AI tools
14%
13%
Privacy and security
9%
5%
Intellectual property concerns over AI-generated code
7%
10%
Lack of context awareness
6%
3%
Poor integration with existing coding and development workflows
The most common concerns include code quality, skill degradation, and AI’s limited understanding of complex code.
How important is each of the following aspects of AI coding assistants, agents, and IDEs for you?
| Not important at all | Slightly important | Moderately important | Very important | |
|---|---|---|---|---|
| 8% | 35% | 26% | 32% | Availability of different AI models / LLMs |
| 15% | 6% | 53% | 25% | Availability of local AI models / LLMs that do not require internet access |
| 2% | 8% | 31% | 60% | Availability of the best AI models / LLMs for coding |
| 5% | 28% | 24% | 42% | Easy-to-use user interface |
| 5% | 30% | 33% | 31% | Frequency of code completion suggestions |
| 0% | 13% | 34% | 53% | Predictability of features’ behavior |
| 7% | 12% | 34% | 47% | Price |
| 1% | 4% | 24% | 71% | Quality of answers in chat |
| 1% | 13% | 26% | 61% | Quality of code completion suggestions |
| 0% | 4% | 11% | 85% | Quality of generated code |
| 1% | 8% | 18% | 73% | Quality of the AI features’ codebase context awareness |
| 4% | 12% | 19% | 65% | Security and privacy |
| 0% | 5% | 31% | 64% | Smooth integration with my IDE or code editor |
| 2% | 27% | 31% | 40% | Speed of code generation (apart from code completion) |
| 2% | 24% | 38% | 37% | Speed of generating code completion suggestions |
| 1% | 15% | 54% | 30% | Speed of response generation in chat |
When using AI, C developers value the quality of generated code, IDE integration, model availability, and predictability of behavior. Speed and privacy also rank highly.