MeTTaScriptA metagraph rewriting database in TypeScript

Store facts in a space, query them by pattern, and compute with rewrite rules. A pure-TypeScript library for the browser, Node, Deno, Bun, and edge. No native addons, no MeTTa knowledge required.

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Use cases

GitHub

A generate-and-test search played as a graph, where candidate answers fan out, are tested, and prune to the results

Use it from TypeScript

Store facts, query by pattern, and write rules with a typed eDSL, entirely in TypeScript. Query keys, arguments, and results cross the boundary as ordinary values. You never have to learn a new language.

A more powerful data model

A metagraph, not a table. Atoms nest, so a fact can be about another fact, and rules and types live in the same space as the data. One pattern-matching mechanism both queries and computes.

Faster than DataScript

On DataScript's own declarative workloads MeTTaScript wins every query at 120k records, up to 1349x, while building faster and holding less heap. See the use-cases page for the full comparison.

Runs anywhere

One core ESM bundle, about 23 KB gzipped. No native addon, no required WASM, no Rust. Import it in a web page, a serverless handler, or an agent loop and go.

TypeScript-native interop

Call your own TypeScript functions from inside rules, drop TypeScript objects straight into the space, and await real I/O. No FFI, same language end to end.

Immutable and concurrent

Keep immutable snapshots you can branch and roll back. Grounded operations can do I/O, and concurrency primitives (par, race, once, with-mutex) and transactions build on top.

Part of the MeTTa ecosystem, if you want it

MeTTaScript implements MeTTa, the language from OpenCog Hyperon, and is validated 270/270 against Hyperon's oracle and the Lean-verified LeaTTa semantics. Use it as a plain library and never think about any of that.