With over 107,000 GitHub stars and adoption by teams at Mozilla, 1Password, Peerlist, and thousands of startups, Supabase has become the most widely deployed open-source Firebase alternative — built entirely on PostgreSQL rather than a proprietary NoSQL store. Every project provisions a dedicated Postgres database with 40+ preinstalled extensions, auto-generating REST APIs via PostgREST, GraphQL via pg_graphql, and real-time change streams via an Elixir-based WebSocket engine that supports database change listeners, user presence tracking, and arbitrary broadcast messaging. Authentication covers email and password, phone OTP, magic links, and 20+ social providers including Google, GitHub, Apple, Azure, and SAML SSO, all enforced through Postgres Row Level Security policies that run inside the database itself. S3-compatible object storage delivers files through a CDN spanning 285+ cities with on-the-fly image transformations powered by imgproxy. Edge Functions run globally distributed TypeScript on the Deno runtime with Node.js compatibility and access to over two million NPM packages. The pgvector extension stores, indexes, and queries vector embeddings for AI-powered semantic search and retrieval-augmented generation workflows. Supabase Studio provides a browser-based dashboard with a table editor, SQL editor, schema visualizer, and log explorer. Official client SDKs ship for JavaScript, Python, Flutter, Swift, Kotlin, C#, Go, and Ruby. The self-hosted Docker Compose stack runs fourteen coordinated services including Kong API gateway, Supavisor connection pooler, and Logflare analytics. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache 2.0 licensed.

Backed by 9,200 GitHub stars and venture funding led by Nauta Capital, Nhost is the open-source Firebase alternative that replaces Google's proprietary document store with a relational PostgreSQL foundation from day one. The Hasura integration auto-generates a real-time GraphQL API with subscriptions, role-based permissions, and remote schemas from your PostgreSQL tables, while event triggers and cron triggers automate backend workflows without custom infrastructure. Authentication supports email and password, magic links, phone OTP via SMS, social OAuth providers including Google and GitHub, WebAuthn for passwordless login with Face ID, fingerprints, and YubiKeys, plus two-factor authentication. Since the Q1 2026 release, Nhost Auth also functions as a full OAuth2 and OpenID Connect provider, allowing your Nhost project to issue tokens to third-party applications the same way GitHub or Google do. The S3-compatible storage service handles file uploads with automatic image optimization, virus scanning, and presigned URLs for secure direct downloads. Node.js serverless functions deploy JavaScript and TypeScript backend logic without managing servers, while the Nhost CLI spins up the complete local stack via Docker for development with automatic database migration tracking and Hasura metadata management. The MCP server integration exposes project documentation and data schemas to AI assistants for intelligent query building. SDKs cover JavaScript, TypeScript, React, Vue, Next.js, and Dart for Flutter. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Backed by over 56,000 GitHub stars and a growing ecosystem of client and server SDKs covering Flutter, React Native, Swift, Kotlin, Python, Node.js, Deno, and more, Appwrite provides a complete backend platform that replaces Firebase and Supabase with a fully self-hostable architecture. The authentication module supports email and password, phone OTP, magic links, OAuth providers including Google, GitHub, Apple, and Facebook, anonymous sessions, and JWT token management with configurable session policies. The database service provides a document-oriented store with collections, indexes, query filters, pagination, and real-time subscriptions that push changes to connected clients instantly via WebSocket. The storage service handles file uploads with built-in image manipulation including cropping, resizing, format conversion, and compression, served through a CDN-ready URL structure. Serverless functions execute custom backend logic triggered by HTTP requests, scheduled cron jobs, or database events, with runtime support for Node.js, Python, PHP, Ruby, Dart, Swift, Kotlin, and Java. The messaging service enables push notifications, SMS, and email delivery through configurable providers including APNS, FCM, Twilio, Vonage, Mailgun, and Sendgrid. Team management with role-based permissions, webhook integrations, and health monitoring APIs complete the platform. The admin console provides a web-based dashboard for managing all services, monitoring usage metrics, and configuring project settings. Deployment runs via Docker Compose with MariaDB for metadata and configurable storage adapters. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. BSD 3-Clause licensed.

An entire backend in a single Go executable: PocketBase embeds SQLite with realtime subscriptions, authentication and user management, file storage, and an admin dashboard, all behind a REST-ish API. SQLite runs in WAL mode, which outperforms client-server databases for the read-heavy workloads typical of small and mid-sized apps. Authentication supports email/password, one-time passwords, and 15+ OAuth2 providers including Google, Apple, and GitHub, with stateless tokens. Clients subscribe to record changes over server-sent events, and official JavaScript and Dart SDKs cover web, mobile, and Flutter frontends. Collections, rules, and API access permissions are managed visually in the admin UI. When you need custom logic, extend it with JavaScript hooks running in the embedded JS VM of the prebuilt binary, or import PocketBase as a Go library and compile custom business logic into your own single-file backend. File storage attaches uploads to records with thumbnail generation for images and optional S3-compatible external storage. All state lives in one pb_data directory, so backup is a directory copy and upgrade is replacing a binary - one of the lowest-maintenance backends you can run. The contrast with Firebase is the point: where usage-based pricing scales with reads, writes, and bandwidth, PocketBase runs the entire backend at flat hosting cost, and the data is a plain SQLite file you can copy anywhere. MIT-licensed.

With 21,400 GitHub stars, 500+ contributors, and battle-tested since its 2016 open-source release after powering Facebook's mobile backend infrastructure, Parse Server delivers production-grade Backend-as-a-Service that eliminates months of custom API development. The platform generates REST and GraphQL endpoints automatically from your data schema with class-level permissions and object-level ACLs providing granular access control. Cloud Code enables server-side JavaScript execution for triggers (beforeSave, afterSave, beforeDelete, afterDelete), custom functions, and scheduled jobs — all deployable without restarting the server. Live Queries push realtime data changes to subscribed clients via WebSockets, powering chat applications, collaborative editors, and live dashboards. Push notification support spans APNs for iOS, FCM for Android, and web push for browsers with audience segmentation, scheduling, and delivery analytics. The Parse Dashboard provides a comprehensive admin interface with a data browser featuring configurable info panels, graph visualization, custom canvas builder with draggable elements, AI agent integration via OpenAI, data import/export, and multi-factor authentication. Database flexibility supports MongoDB 6-8 and PostgreSQL 13-18 with PostGIS for geospatial queries. Native SDKs cover JavaScript, iOS (Swift/Objective-C), Android, Flutter/Dart, .NET/Xamarin, Unity, PHP, and Arduino for IoT devices. Deploy via npm, Docker, or the official Express template with automatic schema migration. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache 2.0 licensed.

Kuzzle ships a production-ready backend from day one: data storage with Elasticsearch search, real-time pub/sub notifications, user authentication, role-based permissions, and a multi-protocol API serving HTTP, WebSocket, and MQTT simultaneously on port 7512. Rather than rebuilding these standard features from scratch for each project, you get a ready-made backend that accepts connections from web applications, mobile clients, and IoT devices through one unified API surface. Elasticsearch provides persistent document storage with full-text search, geospatial queries, and aggregation pipelines, while Redis handles internal caching and memory storage operations. The Koncorde real-time engine powers pub/sub messaging and database notifications, enabling clients to subscribe to document changes with filter conditions that trigger instant updates when matching data is created, modified, or deleted. User management includes JWT-based authentication, role-based access control with granular permissions at the controller and action level, and pluggable authentication strategies via Passport.js. The extensible plugin framework allows developing custom business logic, additional authentication providers, storage connectors, and protocol handlers. Client SDKs for JavaScript, Dart, Kotlin, and C++ accelerate frontend development, while the Kourou CLI provides command-line API access and project scaffolding. The Vue.js Admin Console offers a web interface for managing indexes, collections, documents, users, profiles, and roles. Horizontal scaling through masterless cluster mode targets 99.99% uptime without single points of failure. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache 2.0 licensed.