What it does
QuantLib is an open source library for financial modeling, instrument pricing and risk analysis. The core is written in C++, with bindings for languages including Python, C#, Java and R. Its modified BSD licence permits commercial use subject to the licence conditions.
QuantLib supplies model implementations for developers and quantitative researchers building their own calculations. Begin with the instrument, valuation date, conventions and market inputs needed for the chosen model. A result remains conditional on those choices; the library does not supply a brokerage account or a ready-filled market dataset.
Python users can install the official package with pip install QuantLib and import it as QuantLib. The download page recommends precompiled packages for Python or C# when the underlying library does not need modification. C++ users can build from source; community-provided C++ binaries may lag behind the latest release.
The documentation page links the reference manual and learning resources. Match examples to the version installed in your environment, particularly when moving between a language binding and the C++ reference. The project describes the reference manual as a work in progress.
There is no QuantLib subscription or product-account requirement for the public packages. Redistribution and commercial use follow the modified BSD terms, including retaining the required notices. C# packaging is explicitly experimental, so its suitability needs checking before choosing it for an existing application.
Strengths
- Provides inspectable quantitative models under a permissive licence
- Offers official precompiled Python and C# packages
- Supports several language bindings around the C++ core
Watch out for
- The C# package is described as experimental
- Community C++ binary packages can lag behind source releases
Best for
- Developers embedding instrument pricing in an application
- Quantitative researchers comparing model assumptions and conventions
Sources
- QuantLib scope and language bindings (Oct 27, 2026)
- QuantLib packages and source downloads (Oct 27, 2026)
- QuantLib documentation and learning resources (Oct 27, 2026)
- QuantLib reference manual scope (Oct 27, 2026)
- QuantLib modified BSD licence (Oct 27, 2026)