Astrid SDK — JavaScript SDK for Building Astrid OS Capsules

Introduction

Astrid SDK is the official JavaScript and TypeScript SDK for building capsules — self-contained applications that run on Astrid OS. It provides APIs for state management, identity, inter-capsule communication, and lifecycle hooks, enabling developers to build decentralized applications using familiar web technologies.

What Astrid SDK Does

• Provides typed APIs for capsule lifecycle management (init, suspend, resume, destroy)
• Handles state persistence and synchronization across capsule instances
• Manages user identity and authentication through the Astrid OS identity layer
• Enables inter-capsule messaging and data sharing through structured protocols
• Offers development tooling including a local emulator and hot-reload server

Architecture Overview

The SDK is a TypeScript library that abstracts the Astrid OS runtime APIs behind a developer-friendly interface. Capsules are packaged as standard JavaScript bundles that the Astrid OS runtime loads and sandboxes. The SDK communicates with the host runtime through a message-passing bridge, handling serialization, state checkpointing, and capability negotiation transparently. A companion Rust SDK (sdk-rust) provides equivalent APIs for performance-critical capsules.

Self-Hosting & Configuration

• Install via npm or yarn into any Node.js or browser-based project
• Use the local emulator for development without a full Astrid OS installation
• Configure capsule manifest (permissions, capabilities, resource limits) in astrid.json
• Deploy capsules to Astrid OS instances using the CLI publish command
• TypeScript definitions are included for full IDE autocompletion and type safety

Key Features

• First-class TypeScript support with complete type definitions
• Local development emulator for testing capsules without a running Astrid OS node
• Built-in state persistence API that handles serialization and conflict resolution
• Identity integration for user authentication and capability-based access control
• Hot module replacement during development for rapid iteration

Comparison with Similar Tools

• Electron — builds standalone desktop apps; Astrid SDK targets the Astrid OS capsule runtime
• React Native — cross-platform mobile framework; Astrid capsules are platform-agnostic runtime units
• WASI/WASM — low-level portable binary format; Astrid SDK is a higher-level application SDK
• Deno Deploy — serverless JavaScript platform; Astrid OS is a decentralized runtime, not a cloud service

FAQ

Q: Do I need Astrid OS to develop capsules? A: No. The SDK includes a local emulator for development and testing. You only need Astrid OS for deployment.

Q: Can I use existing npm packages in a capsule? A: Yes, with some limitations. Capsules run in a sandboxed environment, so packages that require native bindings or unrestricted filesystem access may not work.

Q: Is there a Rust SDK as well? A: Yes. The companion sdk-rust provides equivalent APIs for capsules that need native performance.

Q: What platforms does Astrid OS run on? A: Astrid OS runs on Linux, macOS, and Windows. Capsules themselves are platform-independent.

Sources

• https://github.com/unicity-astrid/sdk-js
• https://github.com/unicity-astrid/sdk-js/blob/main/README.md