InterSystems IRIS AlternativesRelational Databases and other similar apps like InterSystems IRIS

SQLite is a software library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine. SQLite is the most widely deployed SQL database engine in the world. The source code for SQLite is in the public domain.

PostgreSQL is a powerful, open source object-relational database system with over 35 years of active development that has earned it a strong reputation for reliability, feature robustness, and performance.

MySQL Community Edition is a freely downloadable version of the world's most popular open source database that is supported by an active community of open source developers and enthusiasts.

MongoDB is a document database with the scalability and flexibility that you want with the querying and indexing that you need

MariaDB is a backward compatible, drop-in replacement of the MySQL® Database Server. It includes all major open source storage engines.

SQL Server delivers on Microsoft’s Data Platform vision by helping your organization manage your data by enabling you to store data from structured, semi-structured, and unstructured documents within the database.

A full-stack, syncing database that runs on both server and client. Pluggable storage (indexeddb, sqlite, durable objects), syncs over websockets, and works with your favorite framework (React, Solid, Vue, Svelte).

Apache CouchDB is a distributed, fault-tolerant and schema-free document-oriented database accessible via a RESTful HTTP / JSON API. It includes incremental map / reduce mechanics for queries and keeps data safe with an append-only datastore.

Cockroach is a distributed key/value datastore which supports ACID transactional semantics and versioned values as first-class features. The primary design goal is global consistency and survivability, hence the name.

EdgeDB is a database designed to solve some fundamental design flaws that make working with databases—both relational and NoSQL alike—unnecessarily onerous.

YDB is an open source Distributed SQL Database that combines high availability and scalability with strong consistency and ACID transactions.

Bolt is a pure Go key/value store inspired by Howard Chu's LMDB project. The goal of the project is to provide a simple, fast, and reliable database for projects that don't require a full database server such as Postgres or MySQL.