Roslyn
Hacker ApprovedRanked 4 of 10 compiler infrastructures by recommenders
Free .NET compiler platform giving developers parsing, semantic analysis and code generation through C# APIs, widely used for code analysis tooling.
Free .NET compiler platform giving developers parsing, semantic analysis and code generation through C# APIs, widely used for code analysis tooling.
12 people gave an opinion
- recommend it
- 11
- criticize it
- 1
- approval share
- 92%
Recommended in 8 of 13 months
- November 2025: not recommended
- December 2025: not recommended
- January 2026: recommended
- February 2026: not recommended
- March 2026: not recommended
- April 2026: recommended
- May 2026: recommended
- June 2026: recommended
- July 2026: recommended
- August 2026: recommended
- September 2026: recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 11 people recommend itNeeds 10 or more, met.
- 11 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 8 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Strong typing and semantic APIs
“With Roslyn APIs, strong typing, structured namespaces, and compiler level semantic information”
Comment from 30 Sep 2026 in “GPT 6.1 Sol: Near-Astra intelligence for a fifth of the price” “Roslyn was designed from day one for IDE scenarios.”
Comment from 22 Jan 2026 in “Tree-sitter vs. Language Servers” Custom static and code analysis
“My VS copilot already writes one-off scripts that use Roslyn to analyze code.”
Comment from 12 Sep 2026 in “Show HN: Graphify C# – Compiler-accurate Find Usages for coding agents” “Roselyn compiler infrastructure which allows for custom static analysis”
Comment from 8 Jan 2026 in “C# is programming language of the year 2025” Fast, precise source parsing
“mechanically and precisely parse the source and safely perform the substitution”
Comment from 27 Jun 2026 in “U.S. government will decide who gets to use GPT-5.6” “we aim for microsecond (not millisecond) parsing”
Comment from 22 Jan 2026 in “Tree-sitter vs. Language Servers” Useful for agentic AI coding
“My VS copilot already writes one-off scripts that use Roslyn to analyze code.”
Comment from 12 Sep 2026 in “Show HN: Graphify C# – Compiler-accurate Find Usages for coding agents” “Yes, roslyn is like a super-power for agentic coding.”
Comment from 12 May 2026 in “If AI Writes Your Code, Why Use Python?”
Other compiler infrastructures people recommend
The four most recommended other compiler infrastructures, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| LLVM | 119 | 96 | 55% | 12 | 6 yrs3 owners | — |
| QBE | 16 | 10 | 62% | 9 | — | — |
| EDG C++ front-end | 15 | 3 | 83% | 2 | — | — |
| RoslynThis page | 11 | 1 | 92% | 8 | — | Approved |
| MLIR | 10 | 4 | 71% | 6 | — | Approved |
What people said
12 of the 14 comments that mention it, newest first. Each links to the original comment.
“the C# compiler is implemented as library with easy support for runtime code generation is also a powerful feature that I've found to be incredibly useful”
“With Roslyn APIs, strong typing, structured namespaces, and compiler level semantic information”
“My VS copilot already writes one-off scripts that use Roslyn to analyze code.”
“open source re-write of C# (Project Roslyn?). All excellent products.”
“The result is less likely to have subtle bugs if it appears to work and gets through a light code review”
“It was a great solution, I would do it again.”
“mechanically and precisely parse the source and safely perform the substitution”
“Yes, roslyn is like a super-power for agentic coding.”
“we aim for microsecond (not millisecond) parsing”
“Roslyn was designed from day one for IDE scenarios.”
“Roselyn compiler infrastructure which allows for custom static analysis”
“Working with the raw Roslyn types is painful at best”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.