Lark parser library for Python
Shares rank 3 of 7 parser libraries by recommenders
A Python parsing library that people recommend for quickly experimenting with grammars and syntax. Critics report that after a while they went back to plain Python, which they found faster.
A Python parsing library that people recommend for quickly experimenting with grammars and syntax. Critics report that after a while they went back to plain Python, which they found faster.
7 people gave an opinion
- recommend it
- 6
- criticize it
- 1
- approval share
- 86%
Recommended in 5 of 13 months
- November 2025: not recommended
- December 2025: recommended
- January 2026: not recommended
- February 2026: recommended
- March 2026: recommended
- April 2026: recommended
- May 2026: not recommended
- June 2026: not recommended
- July 2026: not recommended
- August 2026: not recommended
- September 2026: not recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it doesn’t carry the badge
- 6 people recommend itNeeds 10 or more, not met.
- 6 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 5 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
Fast iteration on grammar syntax
“the speed of experimenting with different syntax/grammars is just insane”
Comment from 10 Dec 2025 in “Revisiting "Let's Build a Compiler"” “so you can iterate fast and get a runtime spec of your grammar”
Comment from 15 Apr 2026 in “Want to Write a Compiler? Just Read These Two Papers (2008)”
Other parser libraries people recommend
The four most recommended other parser libraries, 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 |
|---|---|---|---|---|---|---|
| Tree-sitter | 79 | 15 | 84% | 12 | — | Approved |
| Hardwood Parquet parser | 7 | 0 | 100% | 2 | — | — |
| Lark parser library for PythonThis page | 6 | 1 | 86% | 5 | — | — |
| Kaitai Struct | 6 | 2 | 75% | 5 | — | — |
| Ohm parsing library | 6 | 3 | 67% | 2 | — | — |
What people said
6 of the 7 comments that mention it, newest first. Each links to the original comment.
“I believe lark [1] is the common Python solution.”
“Free tier does everything.”
“so you can iterate fast and get a runtime spec of your grammar”
“We built this while working on https://getlark.ai/ where agents run in sandbox environments to generate end-to-end tests.”
“after a while I just discarded it and went back to straight python, and found it was faster my an order of magnitude”
“the speed of experimenting with different syntax/grammars is just insane”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.