SurrealDB

vs

RxDB

Supabase is a free and open-source self-hosted and SaaS provided alternative to Firebase. With Supabase you can add a realtime REST API to a PostgreSQL without writing a single line of code.

Fauna is the data API for client-serverless applications. It provides web-native GraphQL interface, with support for custom business logic and integration with the serverless ecosystem. Fauna transforms the traditional DBMS into a Data API that gives you all of the capabilities of traditional database, without sacrificing flexibility, scale, and performance. By utilizing a globally-distributed storage and compute fabric, Fauna-powered applications are delivered to end-users fast and reliably on modern security infrastructure.

EdgeDB is a database designed on top of Postgres with the goal of eliminating some of the shortcommings of relation and NoSQL databases.  At first glance, EdgeDB looks like a regular object relational mapper (ORM), however it's far more than that, It's a full-fledged database with a formally-defined query language, a migrations system, a suite of client libraries in different languages, a command line tool, and a soon comming cloud hosting platform. The goal of EdgeDB has been to rethink every aspect of how developers model, migrate, manage, and query their database.

Amazon DynamoDB is a key-value and document database that delivers single-digit millisecond performance at any scale. The database is fully managed, multiregion, multimaster, and durable with built-in security, backup and restore, and in-memory caching for enterprise-scale applications. Amazon DynamoDB is part of Amazon Web Services and integrates well with other cloud-based AWS products.

PouchDB is a free and open-source JavaScript database inspired by Apache CouchDB. The database is designed from the ground-up to run well within modern web browsers. With PouchDB you can create web applications that works as well offline as they do online. PouchDB achives this by storing data locally, then synchronize it with CouchDB and compatible servers when the user get internet access once again. This is especially useful for applications facing countries and regions with lower quality internet connections or unstable infrastructure.

HSQLDB is a relational database engine written in Java, with a JDBC driver, conforming to ANSI SQL:2016. It's the best for Java developers for development, testing and deployment of database applications. HSQLDB provides a small, fast, multithreaded engine and server with memory and disk tables, LOBs, transaction isolation, multiversion concurrency and ACID.