Open-source Decisions alternatives

Windmill is an open-source platform for developers to run internal code as APIs, background jobs, workflows and user interfaces. It is pitched as a self-hostable alternative to Retool, Pipedream and Superblocks and as a simplified version of Temporal, and it automatically generates UIs so a script can be shared and triggered as an internal app.

Scripts can be written in languages including Python, TypeScript, Go, Bash, SQL, PowerShell, Rust and GraphQL. They can be composed into flows or used within richer apps built with its low-code builder. The backend is written in Rust on PostgreSQL, and the README describes it as a very fast self-hosted workflow engine, citing a comparison with Airflow. Sections of its documentation cover main concepts, local development, architecture, security, performance and self-hosting with Docker Compose.

Windmill is open source under AGPLv3, and Windmill Labs sells dedicated instances, commercial support and licenses, so the repository license is listed as 'Other' on GitHub. It suits engineering teams that want to turn existing scripts into reliable internal tools and automations without building each interface by hand.

Corteza is a low-code platform that lets teams build and iterate on CRM, business process, and other structured data applications quickly. It also supports intelligent business process workflows and connects to almost any data source. It is written in Go, with a Vue front end, and released under the Apache-2.0 license. It is maintained by Planet Crust, its founder.

Key characteristics include a standards-oriented approach using established data formats, flat role-based access control that supports complex internal security policies, privacy features that help comply with data protection regulations, accessibility following WCAG 2.1, and an API-centric design that makes integration with external services and other Corteza instances straightforward. Applications can be customized from translations and terminology up to entirely new low-code apps.

Planet Crust offers hosted Corteza cloud instances as the easiest way to start, and a DevOps guide covers self-hosting along with backup, restore, and email relay topics. Corteza suits organizations that want an open-source alternative to proprietary low-code CRM platforms and need control over their data.

Nussknacker is a low-code visual tool for domain experts to build, run and monitor real-time decision algorithms instead of implementing them in code. Decisions such as which offer a customer gets, who receives a marketing message, whether a device needs servicing or whether something is fraud can be authored and deployed without involving IT.

Authors design scenarios in a visual tool using prebuilt components for routing, filtering, data transformation, time-window aggregations in the Flink engine, enrichments from external databases or OpenAPI endpoints and applying ML models. With one click a scenario is deployed, and it can be changed and redeployed later. Two processing modes are supported: streaming, with Kafka as the main interface for input streams and output decisions, and request-response, which exposes HTTP endpoints with OpenAPI definitions. Batch support is in development.

Nussknacker is written in Scala, licensed under Apache-2.0, and can be installed on your own infrastructure, with a managed Nu Cloud offering also referenced in the README. A demo, documentation and quickstart are linked.

Joget is an application platform that combines rapid application development, business process automation and workflow management in a visual, web-based builder. Business and technical teams can use it together to build full enterprise applications without much hand coding, aiming to shorten delivery from months to weeks or days. Apps built on it are mobile ready and cloud ready, and the platform offers APIs for integration and a plugin architecture for extension.

The README describes a marketplace where ready-made apps, plugins and templates can be downloaded, along with a community Q&A forum, a knowledge base, video tutorials, an online academy and translations in more than twenty languages. Deployment is flexible: on-premise, on-demand cloud, Docker, Kubernetes, Cloud Foundry, OpenShift and several cloud marketplaces are listed.

Licensing is split. Joget Community Edition is released under GPL version 3, while the Professional, Enterprise and Large Enterprise editions are covered by a commercial end-user license agreement. The core is written in Java. It suits organizations that want to digitize processes such as approvals and forms with a platform they can run themselves.