Deterministic rule execution for decision systems.
Built on jsonlogic-fast for portable, high-performance JSON-Logic evaluation.
| jsonlogic-fast | Tempus Engine |
|---|---|
| Evaluate a rule against context | Execute rules with metadata and validation |
Raw serde_json::Value output |
Structured decision results |
| Performance-first | Decision-systems-first |
| Stateless evaluation | Foundation for audit, explain, governance |
- Fraud scoring — block, review, or allow transactions based on risk signals
- Credit eligibility — approve/deny with deterministic, auditable logic
- Dynamic pricing — compute fees and discounts from rule definitions
- Policy enforcement — evaluate compliance rules across regulated workflows
- Feature flags — gate features with structured rule logic
- Rust 1.75+
- Python 3.10+
uv
make setup # Build Python bindings
make test # Run Rust core tests
make test-python # Run Python e2e tests (29 tests)
make test-wasm # Run WASM runtime tests (15 tests)
make ci-local # Full quality gate┌──────────────────────────────────────────────────┐
│ Tempus Engine (this repo) │
│ Rule metadata · Rich validation · Domain demos │
│ Foundation for: explain · audit · time layers │
└────────────────────┬─────────────────────────────┘
│ depends on
┌────────────────────▼─────────────────────────────┐
│ jsonlogic-fast (separate repo) │
│ Fast, embeddable, cross-runtime JSON-Logic eval │
│ Rust core · Python bindings · WASM bindings │
└──────────────────────────────────────────────────┘
Tempus-Engine/
├── engine/ # Rust crate: tempus-engine
│ └── src/
│ ├── lib.rs # Re-exports jsonlogic-fast + Tempus extensions
│ └── metadata.rs # Rule metadata (name, version, tags)
├── examples/ # Domain-specific usage examples
│ └── python/
│ ├── fraud_scoring.py
│ └── eligibility.py
├── docs/ # Product documentation
├── tests/
│ └── python/ # Python e2e tests
└── Makefile
| Phase | What | Status |
|---|---|---|
| 1 | Rule metadata, rich validation, domain demos | Done ✅ |
| 2 | Explain mode (decision trace / audit trail) | Done ✅ |
| 3 | Rule chaining & persistence (JSON/YAML) | Done ✅ |
| 4 | Python & WASM bindings | Done ✅ |
| 5 | Time layer (effective-date rule selection) | Planned |
| 6 | Decision database (receipts, replay, hashing) | Planned |
Tempus Engine is licensed under AGPL-3.0-or-later.
| Your use case | AGPL obligation |
|---|---|
| Internal tooling, not network-exposed | No source disclosure required |
| SaaS / API that calls Tempus Engine | Must release your entire application under AGPL |
| Embedding in a closed-source product | Must release product source under AGPL |
| Open-source project (compatible license) | Use freely; keep attribution |
If the AGPL does not fit your business model, contact us to discuss a commercial license.
The underlying evaluation engine (jsonlogic-fast) is MIT OR Apache-2.0 — permissive, no copyleft obligations. Only the Tempus Engine wrapper layer carries the AGPL.