ToolJet

ToolJet is an open‑source, self‑hosted low‑code platform that enables developers to build internal tools, workflows, and AI agents without leaving the codebase. At its core, it provides a visual app builder that abstracts UI rendering and data plumbing while still exposing full programmatic control through JavaScript, Python, and REST APIs. The Community Edition (CE) delivers a rich set of 60+ responsive components, an embedded no‑code database, and support for 75+ external data sources, making it a versatile foundation for rapid prototyping or production‑grade applications. The enterprise‑level ToolJet AI adds natural‑language app generation, AI‑assisted query building, and agent orchestration, but the CE remains fully functional for most use cases.

Technical Stack & Architecture

ToolJet’s architecture is split into a frontend built with React and Vite, a backend powered by Node.js (Express) that exposes GraphQL and REST endpoints, and a database layer based on PostgreSQL. The platform ships as Docker images, enabling deployment on any container‑orchestrated environment such as Kubernetes or a simple docker-compose stack. The backend also includes an embedded NoSQL‑like store (ToolJet Database) that allows developers to create tables and relationships without writing migrations. The system is modular: connectors are implemented as Node.js plugins, which can be added via the ToolJet CLI (@tooljet/cli) and are discovered at runtime. Security is baked in with AES‑256‑GCM encryption for stored secrets, proxy‑only data flow to prevent direct database exposure, and optional SSO via OAuth/OIDC.

Core Capabilities & APIs

• Drag‑and‑Drop UI Builder: Components expose a JSON schema that can be serialized, versioned, and shared. Developers can embed custom widgets by supplying a React component bundle.
• Multi‑Page & Multiplayer Editing: Real‑time collaboration is achieved through WebSocket sync, allowing multiple users to edit the same app with granular access control.
• Data Integration: The connector framework supports SQL, REST, GraphQL, and object storage (S3/MinIO). Custom connectors can be written in Node.js and published to the ToolJet ecosystem.
• Code Execution: JavaScript (ES6+) and Python snippets run in sandboxed containers per request, returning JSON that can be bound to UI elements or used in subsequent actions.
• Event System: Webhooks, schedules, and in‑app events trigger workflows that can include conditions, loops, parallel steps, and external API calls.
• GitSync & CI/CD: Projects can be pushed to GitHub/GitLab, and a built‑in webhook will trigger rebuilds. The CLI supports exporting the app definition as JSON for version control.

Deployment & Infrastructure

ToolJet is designed to run anywhere container‑friendly. The official Docker images are built with multi‑stage builds for minimal footprint, and a Helm chart is available for Kubernetes deployments. For high availability, the platform can be scaled horizontally behind a load balancer; the stateless API layer stores session data in Redis, while PostgreSQL can be replicated. The embedded ToolJet Database is optional; if a production database is preferred, the platform supports any PostgreSQL instance with SSL/TLS.

Integration & Extensibility

The plugin system is a first‑class feature: developers can write connectors, widgets, or even entire microservices that plug into ToolJet’s event bus. The public API allows external services to trigger actions or fetch app state via authenticated HTTP requests. Webhooks are exposed for every action, enabling integration with Slack, Zapier, or custom monitoring tools. The CLI also offers scaffolding for new connectors and a local development server that hot‑reloads changes.

Developer Experience & Community

ToolJet’s documentation covers architecture, API references, and best practices in a concise style. The community edition is released under AGPL‑3.0, encouraging contributions and forks. A growing ecosystem of connectors (over 75) is maintained on npm, and the GitHub repo hosts a vibrant issue tracker with active pull requests. The platform’s UI is built with TypeScript, ensuring type safety for developers extending the system. Moreover, inline comments, mentions, and granular RBAC make it suitable for teams that require audit trails and collaborative editing.

Use Cases

• Internal Ops Dashboards: Quickly assemble monitoring dashboards that pull from Prometheus, Datadog, or custom APIs.
• Workflow Automation: Build multi‑step approval processes that integrate with Slack, email, and CI/CD pipelines.
• Data Entry & CRUD Apps: Use the built‑in database or connect to legacy Postgres/MySQL to expose forms and tables without writing backend code.
• AI‑Powered Prototyping: Generate UI skeletons from natural language prompts and iterate with live code snippets.
• Custom SaaS Extensions: Deploy a self‑hosted instance that plugs into existing IAM systems and exposes custom connectors for partners.

Advantages Over Alternatives

ToolJet offers a balanced blend of low‑code speed and developer control. Unlike purely drag‑and‑drop builders that lock you into proprietary runtimes, ToolJet’s open architecture lets you extend or replace any component. The self‑hosted model removes vendor lock‑in and gives full control over data residency, which is critical for regulated industries. Performance is optimized through server‑side rendering