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    Impressive totalitarian style Multipurpose Application Server for node.js. All decisions are made. Solutions are scaled. Tools are provided and optimized for high load. Ready for applied development and production.
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    Enterprise application server for Node.js: secure, lightweight, interactive, and scalable.


    First Node.js server scaled with multithreading and extra thin workload isolation. Optimized for high-intensive data exchange, rapid development, and clean architecture. Provides everything you need out of the box for reliable and efficient backend, network communication with web and mobile clients, protocol-agnostic API, run-time type validation, real-time and in-memory data processing, and reliable stateful services.

    Weak sides: not a good choice for content publishing including blogs and online stores, server-side rendering, serving static content and stateless services.

    Strong sides: security and architecture for enterprise-level applications, long-lived connections over websocket to minimize overhead for cryptographic handshake, no third-party dependencies.

    Quick start

    API endpoint example: application/api/example.1/citiesByCountry.js

    async ({ countryId }) => {
      const fields = ['cityId', 'name'];
      const where = { countryId };
      const data = await'City', fields, where);
      return { result: 'success', data };

    You can call it from client-side:

    const res = await metacom.api.example.citiesByCountry({ countryId: 3 });

    Metarhia and impress application server way

    • Applied code needs to be simple and secure, so we use sandboxing with v8 isolated contexts, worker threads and javascript closures;
    • Domain code should be separated from system code; so we use DDD, layered (onion) architecture, DI, SOLID and GRASP principles, contract-based approach;
    • Impress supports stateful applications with RPC and client-session sticky to servers; microservices, centralized or distributed architecture;
    • No I/O is faster even than async I/O, so we hold state in memory, share it among multiple threads and use lazy I/O for persistent storage;
    • We use just internal trusted dependencies, no third-party npm packages; total Metarhia technology stack size is less than 2mb.


    • Auto API routing, just create endpoint files as an async function;
    • Code live reload with file system watch (when files change on disk);
    • Graceful shutdown and application state recovery after reload;
    • Minimal dependencies and code size;
    • Can scale with multiple threads and servers;
    • Code sandboxing for security and context isolation;
    • Auto module loader with dependency injection for namespaces;
    • Layered architecture out of the box: core, domain, API, client;
    • Utilize multiple CPU cores and serve multiple ports with worker threads;
    • Inter-process communication and shared memory used for state management;
    • State synchronization mechanism with transactions and subscription;
    • Cache server-side executable JavaScript in memory;
    • Rapid API development support: AJAX RPC and Websocket;
    • Serve static files from memory cache;
    • Application configuration (for different named environments);
    • Database access layer for PostgreSQL and relational db schemas;
    • Persistent sessions support with authentication, groups, and anonymous;
    • Multiple protocols: HTTP, HTTPS, WS, WSS;
    • Logging with buffering (lazy write) and rotation (keep logs N days);
    • File utilities: upload, download, streaming;
    • Built-in simple testing framework;
    • Server health monitoring;
    • Built-in data structures validation and preprocessing library;
    • Task scheduling (interval or certain time);
    • Concurrency control: request queue with timeout and size;
    • Execution timeout and error handling;


    • Node.js v16.0.0 or later (v18 preferred)
    • Linux (tested on Fedora 36, 37, Ubuntu 18, 20 and 22, CentOS 7, 8, 9)
    • Postgresql 11 or later (v14 preferred)
    • OpenSSL v3 or later (optional, for https & wss)
    • certbot (recommended but optional)

    License & Contributors

    Copyright (c) 2012-2023 Metarhia contributors. See github for full contributors list. Impress Application Server is MIT licensed. Project coordinator: <>

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