ContractGate

Semantic Contract Enforcement at Ingestion — Patent Pending

Stop bad data before it reaches your warehouse, lakehouse, or ML pipeline.

ContractGate is a high-performance validation gateway that enforces rich semantic data contracts in real time. Built in Rust for sub-millisecond per-event validation (86k+ events/sec/core), it goes far beyond JSON Schema or basic type checks — ontology, glossary, patterns, enums, computed metrics, and automatic inference.

Live demo → app.datacontractgate.com/stream-demo

Using Claude, Cursor, or Codex? Paste this

Code

https://app.datacontractgate.com/llm-integration.md
https://github.com/nightmoose/contractgate

implement this in my repo

Your agent reads the integration playbook (source), finds your event shape, infers a contract from real samples, deploys it, wires your producer to /v1/ingest, and verifies with a dry run before anything is written. Machine index: /llms.txt.

MCP (Cursor, Claude Desktop, Windsurf, Copilot, Codex):

config.json

{
  "mcpServers": {
    "contractgate": {
      "command": "npx",
      "args": ["-y", "@contractgate/mcp-server"],
      "env": {
        "CONTRACTGATE_API_KEY": "${CONTRACTGATE_API_KEY}"
      }
    }
  }
}

Tools and auth: docs/mcp-reference.md.

Claude Code / Cursor plugin:

Code

/plugin marketplace add nightmoose/contractgate
/plugin install contractgate@contractgate

Redpanda Connect (HTTP processor, no custom plugin): docs/examples/redpanda-connect/.

Try it in 10 minutes (Self-Hosted Free)

No Supabase account. No API keys. No sign-up.

bash

git clone https://github.com/nightmoose/contractgate.git
cd contractgate
make demo

Opens at http://localhost:3000 — dashboard pre-loaded with three starter contracts and a live event stream. First build ~3 min, subsequent runs instant (Docker layer cache).

bash

make demo-reset   # wipe + reseed (clean slate)
make demo-down    # stop and remove volumes
make demo-logs    # follow all service logs

Self-Hosted Free runs the real gateway binary — not a sandbox. Unlimited local events, full YAML editor, playground, audit log. Feature comparison below ↓

Key Features

Semantic YAML Contracts — entities, types, patterns, enums, required fields, glossary, and computed metrics
Real-time Validation — at ingestion (Kafka, HTTP, batch) with sub-millisecond per-event validation
Visual Contract Builder — intuitive UI + live YAML preview (Cloud)
AI-Powered Inference — paste sample JSON → instantly generates a full contract (Cloud)
Quarantine + Replay — automatically hold and replay violating events (Cloud)
Versioned Contracts — draft → stable → deprecated with compliance mode (Cloud)
High Performance — Rust + Axum core, 86k+ events/sec/core
Polyglot — Rust engine, Python SDK, CLI, Kafka Connect, Next.js dashboard

Self-Hosted Free vs Cloud

Capability	Self-Hosted Free	Cloud (Free / Growth / Enterprise)
Validation engine	✅ Unlimited (local)	✅ 1M / 50M / Unlimited events/month
Starter contracts	✅ 3	✅ 3 / Unlimited / Unlimited
Playground	✅	✅
Audit log	✅ Local Postgres	✅ 7 / 90 / Custom days retention
Live event stream	✅	✅
Auth & API keys	❌	✅
Multi-tenancy	❌ Single org	✅
Visual contract builder	❌	✅ Growth+
AI inference (JSON → YAML)	❌	✅ Growth+
Quarantine + replay	❌	✅ Growth+
PII transform rules	❌	✅ Growth+
Semantic versioning UI	❌	✅ Growth+
GitHub sync	❌	✅ Growth+
Team invites & roles	❌	✅ Growth+
SSO / SAML	❌	✅ Enterprise
Managed hosting + SLA	❌ Self-hosted	✅

→ Full pricing → Talk to sales

Other Quickstarts

Docker (gateway + Postgres only):

Terminal

docker compose up

Python SDK:

Terminal

pip install contractgate

server.ts

from contractgate import Client
client = Client(api_url="http://localhost:8080", api_key="cg_demo_key")
client.validate(contract_id="...", event={"user_id": "u1", "event_type": "click"})

CLI:

bash

cargo install --git https://github.com/nightmoose/contractgate contractgate
contractgate validate --contract examples/nested-order.yaml events.json

GitHub Action (compile every YAML under contracts/ on PRs):

yaml

- uses: nightmoose/contractgate/actions/validate@main
  with:
    path: contracts

pre-commit (same compile, no network):

yaml

# .pre-commit-config.yaml
repos:
  - repo: https://github.com/nightmoose/contractgate
    rev: main   # pin to a git sha
    hooks:
      - id: contractgate-validate

Architecture

Layer	Tech
Validation engine	Rust + Axum (sub-millisecond per-event, see note)
Dashboard	Next.js 15 + TypeScript + Tailwind
Storage	Supabase (Postgres + Auth)
Connectors	Kafka Connect, HTTP, batch, Python SDK, CLI
Observability	Prometheus + Grafana

Full RFCs and design docs live in docs/rfcs/. For a quick shipped-vs-draft view, see docs/STATUS.md.

Comparison

Feature	ContractGate	Great Expectations	Soda	Monte Carlo	dbt
Validation timing	At ingestion	Post-hoc / batch	Mix (mostly batch)	Observability	During dbt runs
Performance	Sub-ms per-event, 86k+ ev/s (Rust, see note)	Python-based	Varies	Not a validator	Not real-time
Semantic depth	Ontology + glossary + metrics	Basic expectations	Checks + rules	No contracts	Basic schema
Visual builder	Yes + live YAML	Partial	Limited	No	YAML only
Inference from sample data	One-click JSON → YAML	Profiler (basic)	Limited	No	No
Quarantine + replay	Built-in	No	No	No	No
Versioning	Draft → stable → deprecated	Manual	Basic	No	Basic
Self-hosted OSS	Yes (`make demo`)	Yes	Open core	Commercial	Yes
License	MIT	Apache 2.0	Open core	Commercial	Apache 2.0

Contributing

PRs welcome. See CONTRIBUTING.md and the active punchlist in docs/.

Active RFCs: docs/rfcs/ · RFC status index: docs/STATUS.md

License

MIT — see LICENSE. Free to use, fork, and build on top (commercial use welcome).

The semantic contract enforcement algorithm is the subject of a pending patent. The patent covers the invention — your right to use, modify, and distribute the code under the MIT license is unaffected. See NOTICE for details.

Built with ❤️ in Florida by NightMoose