# Steel Bank Common Lisp (SBCL)

26 Hacker News commenters recommended Steel Bank Common Lisp (SBCL) and 7 criticized it, November 2025 to November 2026. It was recommended in 8 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** Free, fast Common Lisp implementation praised for its compiler, type checking and performance. Common caveat: weaker IDE tooling than commercial Lisps.

## Why people recommend it

- Fun, awesome language to program in (5 comments): "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." ([source](https://news.ycombinator.com/item?id=47150127)) "SBCL is cool! A fun reminder of less majoritarian approaches to SWE." ([source](https://news.ycombinator.com/item?id=47146069)) "It's awesome and the lucky 10,000 deserve to be introduced to it" ([source](https://news.ycombinator.com/item?id=47142313))
- Excellent compiler and generated code (3 comments): "It is probably the best Common Lisp compiler when it comes to type checking." ([source](https://news.ycombinator.com/item?id=47147323)) "the compiler generates code that rivals hand-optimized C" ([source](https://news.ycombinator.com/item?id=47142738)) "SBCL is a very good compiler" ([source](https://news.ycombinator.com/item?id=45788918))
- Performance handles large workloads (2 comments): "performance increased so much that even the largest discussions no longer need splitting" ([source](https://news.ycombinator.com/item?id=47142202)) "the compiler generates code that rivals hand-optimized C" ([source](https://news.ycombinator.com/item?id=47142738))
- Reliable with few dependencies (2 comments): "SBCL allows you to create working stuff with very few dependencies" ([source](https://news.ycombinator.com/item?id=49257839)) "works really well, don't knock it until you've tried it" ([source](https://news.ycombinator.com/item?id=47142774))

## What people warn about

- Heap exhaustion and GC crashes (4 comments): "there was a major slowdown last night, ending in SBCL dying from heap exhaustion" ([source](https://news.ycombinator.com/item?id=47142999)) "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" ([source](https://news.ycombinator.com/item?id=49280402)) "SBCL doesnt know when it's running low on available heap space?" ([source](https://news.ycombinator.com/item?id=47150648))
- Weak IDE and tooling (2 comments): "I wish sbcl, the defacto best open source option had better tooling" ([source](https://news.ycombinator.com/item?id=47142509)) "it lacks the IDE tooling from LispWorks and Allegro" ([source](https://news.ycombinator.com/item?id=49244198))

## Alternatives hackers recommend

- [SBCL Common Lisp](https://hackerapproved.com/p/sbcl.md): 49 recommend
- [LispWorks](https://hackerapproved.com/p/lispworks.md): 6 recommend
- [Dotcl](https://hackerapproved.com/p/dotcl.md): 6 recommend
- [ECL (Embeddable Common Lisp)](https://hackerapproved.com/p/ecl.md): 5 recommend
- [Clozure Common Lisp](https://hackerapproved.com/p/clozure-common-lisp.md): 5 recommend

## Cite as

Hacker Approved, "Steel Bank Common Lisp (SBCL)", https://hackerapproved.com/p/steel-bank-common-lisp/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).