EYE
The original Euler Yet another proof Engine: a mature N3 and RDF Surfaces reasoner with proof output.
Choose a reasoner
The EYE family offers several implementations and runtimes. Choose the one that best matches your environment, integration needs, and reasoning workload.
eye-js
The original EYE engine compiled to WebAssembly and packaged for browser and Node.js applications.
Eyeling
A compact N3 reasoner for Node.js, browsers, RDF pipelines, streaming messages, and accountable proofs.
Pyling
A Python port of Eyeling for N3 reasoning from Python code, notebooks, RDFLib graphs, or the command line.
Eyeron
A Rust-based N3 reasoner that turns facts and rules into conclusions with verifiable proofs.
Romeo
A fast, dependency-free forward-chaining N3 reasoner descended from Eyeling and distributed as a static binary.
Try one in your browser
These hosted playgrounds let you edit and run examples without installing a local reasoner.
eye-js example
Run the original EYE reasoner in a browser.
Eyeling playground
Experiment with the compact JavaScript engine.
Eyeron playground
Reason with the Rust implementation through WebAssembly.
Eyeleng playground
Try SRL and RDF Rules in a self-contained browser UI.
Eyepl playground
Explore a small Prolog-like reasoning language.
A shared starting point
Many of the N3 engines can begin with the same familiar Socrates example: facts and an implication go in; a new, explainable conclusion comes out.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix : <http://example.org/socrates#>.
:Socrates a :Human.
:Human rdfs:subClassOf :Mortal.
{ ?S a ?A. ?A rdfs:subClassOf ?B }
=>
{ ?S a ?B }.Wider EYE ecosystem
Not every related project is another implementation of the EYE N3 engine. These close neighbours explore other rule languages, runtimes, and reasoning models.
- eyelet — portable Prolog reasoning with eyelet clauses
- Eyeleng — SHACL 1.2 Rules in JavaScript
- Eyepl — Prolog-like Horn clauses in JavaScript
- lingua — RDF/TriG graph rules
- rdfsurfaces-tests — RDF Surfaces test kit
- Notation3-By-Example — practical N3 examples
Looking for the broader reasoner landscape? Jos De Roo maintains an overview spanning N3, RDF Surfaces, Datalog, SHACL Rules, RIF, and first-order logic: view the full reasoners list.