Open Source OutSystems Alternatives
A curated collection of the 2 best open source alternatives to OutSystems.
The best open source alternative to OutSystems is Structr. If that doesn't suit you, we've compiled a ranked list of other open source OutSystems alternatives to help you find a suitable replacement. Other interesting open source alternative to OutSystems is Convertigo.
OutSystems alternatives are mainly Frameworks & Platforms but may also be Integration Platforms. Browse these if you want a narrower list of alternatives or looking for a specific functionality of OutSystems.
Low-code platform where an application's schema, interface, scripts and data all live in one graph database, for teams building custom systems.
Structr stores an application's schema, UI definitions, templates, scripts and workflows in the same graph database as the records they operate on. It is a generic development and runtime platform, not a prebuilt CMS or CRM, and it removes the split between a source tree, a schema migration and the data underneath.
Development happens in a web-based developer and administration interface instead of a raw code tree. Types, properties and relationships are modeled in a schema editor, pages are assembled from templates and repeaters bound to graph queries, and logic is written as methods and function properties. GraalVM makes the scripting polyglot, and schemas import and export as JSON Schema.
Around that graph sit the operational pieces an application needs.
- Virtual filesystem: files and binary content with custom metadata, optionally on S3 compatible storage.
- Access control: users, groups, role-based and resource-based permissions, REST scoping and CORS.
- Graph exploration: a visual browser, Cypher execution and interactive inspection of nodes and relationships.
- Workflows: a node-based flow editor for orchestration logic, with inspection of results.
- Integration: REST and JSON APIs, AMQP, Kafka, Pulsar, XMPP, SMTP and IMAP mail, OAuth and LDAP identity.
- AI access: MCP support, so agents work through explicit schemas and defined APIs rather than loose code.
The backend is Java on GraalVM JDK 25 over Neo4j 4.4 or later, deployable as a monolith or in containers under Docker, Podman or Kubernetes. Licensing is dual: AGPL v3 or GPL v3 for open source use, with a commercial license, support and EU-based hosting from Structr GmbH.
Low code and no code platform for building enterprise web and mobile apps with a back end server, IDE and app builder.
Convertigo is a full stack low code and no code platform for building business applications together with the back end they run against. It exists so a team can assemble a cross-platform enterprise app without hand writing the connector, synchronization and delivery layers underneath it.
The Community Edition is not one application but a set of parts, each aimed at a different person on the team, and the server can be installed in more than one shape.
- Convertigo Server: the back end running connectors, micro-services and offline device synchronization, and serving web, mobile and PWA apps.
- Convertigo Studio: an Eclipse based IDE for Windows and macOS where micro-service workflows are programmed and the Mobile Builder assembles interfaces in low code mode.
- No Code Studio: a browser based builder for form driven web apps and PWAs, aimed at citizen developers rather than programmers.
- Container install: the server runs directly from Docker Hub images or through a published Helm chart.
- Servlet install: releases also ship as a Tomcat WAR file for an existing application server.
Convertigo states that more than 150,000 developers worldwide use the platform to build enterprise class web and mobile apps. The Community Edition is AGPL based and comes from Convertigo SA, which makes it a fit for an organization that wants a back end as a service it can run on its own premises rather than a hosted app builder.
