Case study · Nexxt Nest Group
A live SaaS that turns a builder's site notes into the documents the law and their cashflow depend on, with real subscription billing behind it.
Victorian builders spend their evenings producing documents their cashflow depends on: Security of Payment Act progress claims, WorkSafe-format SWMS, site diaries, variations, quotes. A progress claim done properly takes hours; done badly, it can cost the builder an adjudication.
Seventeen AI-powered tools: SOP Act–formatted progress claims from raw notes in about a minute, SWMS generation, a voice-capable site diary, a defect & variation log that turns issues into formal variation orders, a plan reader that lets a builder interrogate a drawing set, a quote generator seeded with Victorian trade rates, a subcontractor register with licence and insurance expiry alerts, extension-of-time notices, and a daily supervisor brief.
Progress claims are drafted by AI from the builder's own notes into the Security of Payment Act 2002 (Vic) claim format. Quotes use indicative Victorian trade rates that the builder checks and edits. Every output is a draft that needs professional review before it is used, and the tool is not legal advice.
Grounding. An AI that invents a contract sum is worse than useless, so every AI call runs through a server-side context assembler that grounds the model in that project's live data, and every output carries advisory-only framing.
The reactive engine. Site-diary weather delays automatically build the evidentiary basis for extension-of-time notices, and a build-stage model predicts obligations ahead of time, so the message is "it's coming," not "you missed it."
Real commerce. This isn't a demo: Stripe subscriptions run live, with webhook reconciliation and entitlements enforced server-side, so a cancelled card actually downgrades the account.
Job sites have no signal. Field capture is offline-first with automatic sync when reception returns.
A hand-written Content-Security-Policy with a live violation-report endpoint, HSTS, row-level-security tenant isolation, server-side entitlement checks on every AI route, daily request caps and rate limiting. Four production cron jobs run the daily briefs and compliance digests. About 42,000 lines of code, 420 commits and an automated test suite (1 Oct 2026).
The product is its own demo: sign up on the free tier with no card and generate a formatted progress claim in about sixty seconds. The site deliberately shows no testimonials; the placeholder literally says we'd rather show nothing than make them up.
A complete commercial SaaS shipped and kept running by one developer, covering product design, AI integration that respects a regulated domain, real payments, scheduled operations and security hardening.