Steel Bank Common Lisp (SBCL)
Hacker ApprovedRanked 2 of 6 common Lisp implementations by recommenders
Free, fast Common Lisp implementation praised for its compiler, type checking and performance. Common caveat: weaker IDE tooling than commercial Lisps.
Free, fast Common Lisp implementation praised for its compiler, type checking and performance. Common caveat: weaker IDE tooling than commercial Lisps.
33 people gave an opinion
- recommend it
- 26
- criticize it
- 7
- approval share
- 79%
Recommended in 8 of 13 months
- November 2025: recommended
- December 2025: recommended
- January 2026: not recommended
- February 2026: recommended
- March 2026: not recommended
- April 2026: recommended
- May 2026: not recommended
- June 2026: recommended
- July 2026: recommended
- August 2026: recommended
- September 2026: recommended
- October 2026: not recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 26 people recommend itNeeds 10 or more, met.
- 3.7 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
Fun, awesome language to program in
“I credit Common Lisp (and SBCL in particular) with being the thing that actually convinced me that there was something interesting about programming in its own right.”
Comment from 25 Feb 2026 in “Steel Bank Common Lisp” “SBCL is cool! A fun reminder of less majoritarian approaches to SWE.”
Comment from 25 Feb 2026 in “Steel Bank Common Lisp” “It's awesome and the lucky 10,000 deserve to be introduced to it”
Comment from 24 Feb 2026 in “Steel Bank Common Lisp” - Comment from 25 Feb 2026 in “Steel Bank Common Lisp”
- Comment from 25 Feb 2026 in “Steel Bank Common Lisp”
Excellent compiler and generated code
“It is probably the best Common Lisp compiler when it comes to type checking.”
Comment from 25 Feb 2026 in “Steel Bank Common Lisp” “the compiler generates code that rivals hand-optimized C”
Comment from 24 Feb 2026 in “Steel Bank Common Lisp” “SBCL is a very good compiler”
Comment from 2 Nov 2025 in “Hard Rust requirements from May onward” Performance handles large workloads
“performance increased so much that even the largest discussions no longer need splitting”
Comment from 24 Feb 2026 in “Steel Bank Common Lisp” “the compiler generates code that rivals hand-optimized C”
Comment from 24 Feb 2026 in “Steel Bank Common Lisp” Reliable with few dependencies
“SBCL allows you to create working stuff with very few dependencies”
Comment from 11 Aug 2026 in “Chicken Scheme 6.0 Released” “works really well, don't knock it until you've tried it”
Comment from 24 Feb 2026 in “Steel Bank Common Lisp”
What people warn about
Each mark is one comment
Heap exhaustion and GC crashes
“there was a major slowdown last night, ending in SBCL dying from heap exhaustion”
Comment from 24 Feb 2026 in “Steel Bank Common Lisp” “One annoying part of SBCL is that it does something up front with its memory such that if you run it with an 8GB heap”
Comment from 13 Aug 2026 in “Why vibe code in Common Lisp?” “SBCL doesnt know when it's running low on available heap space?”
Comment from 25 Feb 2026 in “Steel Bank Common Lisp” - Comment from 25 Feb 2026 in “Steel Bank Common Lisp”
Weak IDE and tooling
“I wish sbcl, the defacto best open source option had better tooling”
Comment from 24 Feb 2026 in “Steel Bank Common Lisp” “it lacks the IDE tooling from LispWorks and Allegro”
Comment from 10 Aug 2026 in “Because It's Not Fun Enough: why languages fail”
Other common Lisp implementations people recommend
The four most recommended other common Lisp implementations, 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 |
|---|---|---|---|---|---|---|
| SBCL Common Lisp | 49 | 9 | 84% | 11 | — | Approved |
| Steel Bank Common Lisp (SBCL)This page | 26 | 7 | 79% | 8 | — | Approved |
| LispWorks | 6 | 6 | 50% | 6 | — | — |
| Dotcl | 6 | 0 | 100% | 2 | — | — |
| ECL (Embeddable Common Lisp) | 5 | 0 | 100% | 5 | — | — |
What people said
34 of the 35 comments that mention it, newest first. Each links to the original comment.
“One annoying part of SBCL is that it does something up front with its memory such that if you run it with an 8GB heap”
“SBCL allows you to create working stuff with very few dependencies”
“Arguably the best is SBCL”
“it lacks the IDE tooling from LispWorks and Allegro”
“the best bet right now is start using SBCL in your daily work”
“It's worse than Java and Python and JavaScript I think?”
“I much prefer it to writing intrinsics in C”
“Stuff like this needs some decent documentation in order to be able to use a low level feature like this properly.”
“Good technique, and compress the image so executables are fairly small.”
“SBCL works fine on Windows.”
“Great to see the project is still going strong”
“These seem like pretty awesome additions.”
“SBCL is not something you embed in an application written in another language”
“They definitely do embrace merging AI slop now, so they might even take pull requests.”
“letting model+tools run sbcl is sufficient”
“I have also seen some outright crashes on the new GC.”
“SBCL doesnt know when it's running low on available heap space?”
“I credit Common Lisp (and SBCL in particular) with being the thing that actually convinced me that there was something interesting about programming in its own right.”
“possibly my favorite error message”
“It is probably the best Common Lisp compiler when it comes to type checking.”
“SBCL is cool! A fun reminder of less majoritarian approaches to SWE.”
“I love SBCL because it's awesome, and I hate it because it's ruined programming for me.”
“knowledgeable about SBCL and its awesomeness”
“there was a major slowdown last night, ending in SBCL dying from heap exhaustion”
“works really well, don't knock it until you've tried it”
“the compiler generates code that rivals hand-optimized C”
“I wish sbcl, the defacto best open source option had better tooling”
“It's awesome and the lucky 10,000 deserve to be introduced to it”
“While great option, LispWorks and Allegro Common Lisp should not be overlooked”
“performance increased so much that even the largest discussions no longer need splitting”
“SBCL is obviously fantastic but let's contrast with another popular implementation”
“launch Emacs with sbcl and write some Montecarlo simulations”
“they didn't seem appropriate for the commercial programming I'm used to”
“SBCL is a very good compiler”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.