LeaseLens

Lease review for South African landlords, rental agents and property managers. Upload a residential lease (PDF, Word or text) and get the key terms, a clause checklist and red-flag wording in seconds. Pro subscribers get a clause-by-clause AI review powered by an open-source model on Hugging Face Inference Providers.

How it makes money

Plan	Price	What's included	Cost to run
Free	R0	10 quick scans a month (rule engine)	Nothing: runs on the free server CPU
Pro	PRO_PRICE_LABEL via Paystack	Unlimited quick scans + 100 AI reviews a month	A few cents of inference per review

The free tier costs nothing to serve, so it can be generous and drive signups. The paid tier is the only one that spends inference credits, so revenue arrives before cost.

Architecture

Browser ──> FastAPI (app/main.py) in Docker on Render (free web service)
             ├─ /            landing page (SEO, pricing)
             ├─ /app         the tool (upload, scan, report)
             ├─ /api/*       signup, scan, checkout, subscription management
             ├─ /paystack/webhook  signed Paystack events → plans + revenue (default)
             ├─ /billing/callback  instant Pro activation after checkout
             ├─ /stripe/webhook    optional alternative gateway
             ├─ /admin       operator dashboard (HTTP Basic, ADMIN_PASSWORD)
             └─ /health      uptime probe
            app/analyzer.py  rule engine (free) + HF LLM review (Pro), with automatic fallback
            app/payments/    Paystack (default) and Stripe gateways on shared, idempotent billing logic
            app/tasks.py     heartbeat, dependency checks, change-triggered backups to a private HF dataset, pruning
            app/db.py        SQLite (accounts, counters, logs, billing events; never documents)

Run locally

pip install -r requirements-dev.txt
pytest -q    # 14 tests: scanning, quotas, Paystack + Stripe lifecycles, MRR, admin auth, AI fallback
ADMIN_PASSWORD=dev PAYSTACK_SECRET_KEY=sk_test_dev PAYSTACK_PLAN_CODE=PLN_sim uvicorn app.main:app --port 7860
python scripts/simulate_payment_events.py --secret sk_test_dev --email you@example.com   # after creating a key in the app

See LAUNCH_CHECKLIST.md for going live and .env.example for every setting.

LeaseLens highlights issues for review. It isn't legal advice.