Chemfp licenses

chemfp has two development tracks. The 1.x track is available for no cost under the MIT license, and multiple licensing options are available for the 4.x track.

Chemfp 4.x licensing

The most recent versions of the 4.x track are available with several different licensing options. Use one of the buttons below to request an evaluation license key, or email

Most customers opt for a source license. This comes with the source code (which works on macOS and Linux-based OSes) and a year of support, which includes email support, free updates to any new releases during the year, and the option to renew support at fraction of the list price.

In addition, the source license has no time limit, no license manager, and the right to modify and maintain chemfp even without a support contract. This helps you avoid vendor lock-in and avoid licenses expiring unexpectedly.

Binary licensing for the Linux-based Python package is also available, with a time-limited license key.

1. The Chemfp Base License

Pre-compiled Python packages for most Linux-based OSes are available for download under the Chemfp Base License Agreement. This can be installed using:

python -m pip install chemfp -i

This license lets you use most chemfp features in-house, and generate FPS files for any purpose.

Some features are either limited or disabled. The Base License does not permit you to:

These features can be enabled with a time-based license key. Use one of the options below to request an evaluation license key.

2. Single-site in-house commercial license

The single-site license is for companies which will only use chemfp at a single geographic location. This might be a small company with only one location, or a single research group in a world-wide company, or a self-employed person. Special consideration may be made for small but distributed groups.

The location is determined by where the people generally work, not where the software is used. For example, chemfp may be deployed on remote cloud-computing hardware so long as the users of the software generally work at one place. (This will be interpereted generously as many people are working from home because of the pandemic.)

Customers may purchase a long-term license key for the binary package, or opt for source code access. Source code licenses are not time-limited.

3. World-wide in-house commercial license

The world-wide source license or world-wide binary license is for companies which will deploy chemfp any place in the world for in-house use, including deployment on remote cloud servers.

Customers may purchase a long-term license key for the binary package, or opt for source code access. Source code licenses are not time-limited.

4. Academic license

The academic license is for public research and education. It can be used for research where the results are meant to be published in the open literature, in the development of web servers which are meant for general public use, and for student use where the goal is education or training.

Academics may request a no-cost one year license key for the pre-compiled binary. No support is included in this option.

Academics may also purchase access to the chemfp source code under this license.

5. MIT/Open source license

Chemfp is also available under the MIT open source license. This is a permissive license which lets you use chemfp for almost any purpose, including reselling it.

One of the goals of the chemfp project was to experiment with funding a pure open source software project through commercial sales. The business model was that people would pay for chemfp and receive the source code as open source.

Experience showed some of the problems selling open source software. For example, the economic risk of selling to academics - who typically expect greatly reduced rates - meant that it was only sold to industrial customers.

The results of the experiment lead to the different licensing options listed above.

Open source licensing is still available, though it is the most expensive option by far.

Chemfp 1.x licensing (No-cost and Open Source)

Chemfp 1.6.1 is the most recent version of the chemfp 1.x track. Be aware that it only works on Python 2.7, which is no longer supported by the modern versions of RDKit, Open Babel, or OEChem. The primary goal of chemfp 1.6.1 is to provide a good reference baseline for evaluating Tanimoto similarity search performance.

You can download chemfp 1.6.1 directly or install it from PyPI using

python2.7 -m pip install chemfp

This version of chemfp is distributed under the MIT license. Some third-party components which are distributed under a similarly permissive license. For license details, see the license section of the chemfp 1.6.1 documentation.

Contact if you have questions.