Famous software or companies built with Lisp
Executive summary
Lisp has powered both pioneering products and obscure but influential engineering systems from the 1960s to today: commercial Lisp machines and companies like Symbolics, mission-critical aerospace and scheduling software at NASA, and modern services such as ITA’s airfare engine and Grammarly’s grammar engine all have clear Lisp pedigrees [1] [2] [3] [4]. While Lisp is no longer mainstream for consumer apps, a steady ecosystem of companies and projects continues to use Common Lisp and other dialects for specialized, high-leverage systems in AI, scientific computing, quantum research and developer tooling [5] [6] [4].
1. The 1980s giants: Lisp machines and Symbolics rewrote what software could do
In the heyday of specialized hardware for AI research, companies like Symbolics commercialized Lisp Machines that bundled a Lisp environment with bit-mapped displays, windowing and animation tools, enabling a class of interactive, graphics-heavy applications that were otherwise hard to build on general-purpose machines [1]. That era helped solidify Lisp’s reputation for enabling rapid experimentation in AI and human–computer interaction, even as the commercial Lisp-machine market later contracted [1].
2. Airline search, scheduling and space missions: mission-critical Lisp
Multiple high-profile engineering and aerospace systems were implemented in Common Lisp: NASA’s Deep Space 1 autopilot and mission-planning systems such as Mars Pathfinder and SPIKE for observatory scheduling are documented examples of Lisp in production for space operations [2]. In commercial travel tech, ITA Software’s airfare search and scheduling platform — historically cited as a standout Lisp application — became a backbone for large-scale fare computation before and after its acquisition by Google [3] [4].
3. Modern enterprise and AI: Grammarly, Ravenpack, and niche innovators
Contemporary companies continue to run critical codebases in Common Lisp: Grammarly’s core grammar engine and RavenPack’s analytics tooling are among cited modern engines built with Lisp technology, demonstrating that the language still underpins large language-processing and analytics systems [2] [4]. Startups and smaller firms — including document-processing companies and firms in quantum and scientific research — also report active Common Lisp use in production code [4] [5].
4. Research, quantum computing and specialized toolchains
Lisp survives in research-heavy domains where expressivity and rapid prototyping matter: D-Wave has reported using Common Lisp (SBCL) as part of its quantum stack, and laboratories and R&D groups employ SBCL and other implementations for compiler and algorithm work [4] [5]. Academic and open-source projects — from audio composition systems to symbolic algebra implementations like Maxima — further show Lisp’s enduring place in domain-specific toolchains [6] [7].
5. Developer tooling and extensibility: Emacs, SKILL and domain scripting
Lisp dialects are also embedded as extensibility layers inside larger systems: Emacs’s extensibility is driven by Emacs Lisp, making it a canonical example of a massively extensible editor built around Lisp [8]. In electronic design automation and CAD, Autodesk’s SKILL (a Lisp descendant) has been used as a scripting language for complex EDA workflows, illustrating how Lisp family languages often survive as domain-specific scripting engines [9].
6. Why Lisp shows up where it matters — and where reporting exaggerates
The common thread across these examples is not mass-market ubiquity but strategic concentration: Lisp tends to appear in systems that benefit from high expressiveness, live development and symbolic processing, from aerospace scheduling to language engines [2] [4]. Popular narratives sometimes overclaim broad dominance (for example suggesting Lisp built “AI” in general); the evidence points instead to selective but deep use in high-leverage systems and in research contexts where those language features pay off [3] [1].
7. The ecosystem today: companies, community lists and living projects
Community-maintained directories and curated “awesome” lists catalog active Lisp companies and projects — from AllegroGraph and commercial Lisp vendors to GitHub collections and company pages — which are practical resources for tracing who uses Lisp now and for what [9] [6] [5]. Those lists show a dispersed but resilient ecosystem: aerospace, finance, developer tools, music and scientific computing remain visible pockets where Lisp is chosen deliberately rather than by accident [6] [5] [4].