Alloy Project Overview

Alloy Project Overview

On November 20, 2019, at FINOS' flagship conference, the Open Source Strategy Forum, FINOS Platinum member Goldman Sachs announced its intention to open source two products - a modeling language internally named "PURE", and a visual modeling platform that generates PURE models known in Goldman Sachs as "Alloy" - into FINOS. 


What is PURE?

PURE is a modeling language inspired in part by languages such as the Object Constraint Language (OCL) and UML. PURE also has many elements of a functional programming language. Goldman Sachs uses PURE to create and construct internal models for functions such as reporting and clearing. 


Alloy is a visual modeling environment and system that creates, maintains, and helps distribute models built in PURE. Behind the scenes, Alloy uses git, (fellow FINOS member) Gitlab for its SDLC (software development lifecycle), and standard source control concepts to manage changes to, and reviews of, models. Alloy can also generate code in languages and formats such as SQL, JSON, JSON Schema (and, internally to Goldman Sachs, SLANG) in order to import and update target systems & infrastructure w/ revised model definitions/extensions.

how and when WILL PURE & Alloy BE open Sourced?

The open sourcing of PURE & Alloy is happening in 3 phases:

  • Phase 0 (Q4 2019 - Q1 2020): Stand-up and deploy an external instance of Alloy for shared modeling; Open Source Strategy Forum announcement; internal code evaluation and preparation for open sourcing

  • Phase 1 (Q1 2020 - Q2 2020): Until now PURE and Alloy were internal-only tools to Goldman Sachs. Gathering and incorporating external feedback about how PURE/Alloy are used amongst multiple organizations collaborating on model development is important to the preparation of the code base as it's released as open source software.

    To collect this input, and build an initial community of PURE/Alloy modelers and developers, during Phase 1
    a pilot group of FINOS members and other strategic industry participants will develop common, shared PURE models. This work will allow Goldman, together with the emerging external PURE/Alloy community, to create an initial backlog of Alloy features for developers to work on and to identify suggested domains within the industry (e.g., financial products) for future modeling in PURE.

  • Phase 2 (Mid 2020): Complete technical and legal reviews of code for release per FINOS contribution process; make underlying PURE and Alloy code bases available as open source under an Apache 2.0 license in a FINOS GitLab or GitHub repository. Begin accepting pull requests into PURE and Alloy from developers outside Goldman Sachs. Expand scope of common models built in PURE using Alloy.

For more information about PURE/Alloy, including some of the motivations behind the decision to open source these two products, see the PURE/Alloy press release.


The first two areas that the pilot group will model will be

  • Using the FX Option in the ISDA CDM as a starting point, extend and expand the FX Option model
  • Commodity Reference Data, especially in the context of swaps

Other areas that the Phase 1 pilot group have discussed as potential areas to model together in Alloy include Environmental, Social and Governance (ESG) data as well as potentially continuing some of the work started by the FINOS Financial Objects program on RFQ in the context of interest rate swaps.


The Goldman Sachs team has created a documentation site on Alloy available at

Alloy demo

Pierre DeBelen, Managing Director and head of the Data Model Engineering team at Goldman Sachs gave a demo of the Pure / Alloy contribution during the FINOS Open Source Strategy Forum this past November. Click here to see that demo.


Ask here any questions about PURE/Alloy you might have. You may also use this form to let us know that you or your organization may be interested in participating in the ongoing Q1 2020 pilot of Alloy with industry participants.


General meetings to deliver updates and present demos of PURE/Alloy, as well as answer questions, happen the third Thursday of each month at 10:30am ET. The next such general meeting will take place February 20th.

Sign-up for PURE/Alloy updates below to be notified of call-in and WebEx details for upcoming general meetings.

PURE/Alloy Question and Pilot Interest Form