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 - its internally developed modeling language, "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 pricing, risk assessment, reporting, clearing, and human resources. 


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 Alloy BE open Sourced?

The open sourcing of  Alloy is happening in 3 phases:

  • Prep: Phase 0 (October 2019 - January 2020; Completed): 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

  • Pilot: Phase 1 (January to September 2020; In Progress): 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 are developing common, shared PURE models. This work is allowing 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. Crucially, the pilot group is also creating models relevant and ready for use within the financial services industry.

  • Open Source: Phase 2 (September 2020-): Complete technical and legal reviews of code for release per FINOS contribution process; make underlying code bases of Alloy SDLC, Execution, and Studio components, as well as PURE, available as open source under an Apache 2.0 license. Begin accepting pull requests into Alloy from developers outside Goldman Sachs. Expand scope of common models built in PURE using Alloy. Prepare for and release 2nd wave of code - tentatively Cube, Graph, and Services - in early 2021. 

For more details about the open sourcing roadmap, see the roadmap on the Alloy documentation site ( For more information about some of the motivations behind the decision to open source Alloy, see the press release from last November announcing Goldman Sachs' intention to open source Alloy into FINOS


The first two areas that the pilot group will model is:

Other areas that the pilot group have discussed as potential areas to model together in Alloy, either during the pilot or down the road, 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 an Alloy documentation site at

Alloy demo

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


General meetings to deliver updates and present demos of Alloy, as well as answer questions, happen the third Thursday of each month at 9:00am ET / 14:00 UK. The next such general meeting is scheduled for October 15, 2020


Use the form below to request an account on the FINOS shared (public) instance of Alloy (