Introduction

MarsDB is an embeddable property-graph database with an openCypher query subset: single binary, single file, optional in-memory mode. No server process, no network protocol — it links into your Rust, Python, or Go program (or runs standalone via the marsdb CLI) the same way SQLite does for relational data.

$ marsdb :memory:
MarsDB graph database. Enter Cypher statements terminated by `;`. Ctrl-D to exit.
marsdb> CREATE (a:Person {name: 'Alice'})-[:KNOWS]->(b:Person {name: 'Bob'});
marsdb> MATCH (a:Person)-[:KNOWS]->(b:Person) RETURN a.name, b.name;
a.name | b.name
Alice | Bob

Why a graph database

Relational databases model connections as foreign keys and join tables; finding them back out means more joins, one per hop, and the query gets harder to write and slower to run as the path gets longer. A graph database stores the connection itself as a first-class thing, so “friends of friends,” “the shortest path between these two people,” or “everyone reachable within three hops” are direct pattern matches, not a chain of joins.

Why MarsDB specifically

• A real subset of openCypher, not a lookalike. Checked against the openCypher Technology Compatibility Kit on every push. See the Cypher Language Reference for exactly what’s covered.
• Embeddable, not a server. Database::open("path/to.db") or Database::in_memory() and you’re running queries — no daemon to manage, no port to bind, no client/server protocol.
• Crash-safe by construction. Every Cypher statement runs inside one transaction; storage runs on redb, a pure-Rust MVCC single-file engine.
• Bindings, not just a Rust crate. Python (PyO3, prebuilt wheels) and Go (cgo against a small C ABI) both work today.

Where to go next

• New to MarsDB? Start with Getting Started.
• Want a Cypher walkthrough? The Cypher Guide.
• Integrating into a program? Embedding in Rust, Python bindings, or Go bindings.
• Wondering exactly which Cypher features are supported? See the Cypher Language Reference.
• Curious how it’s built? See Performance, or the Internals appendix.

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.