PropertyHQ
A modular SaaS platform for contractors — 160+ plans shipped across 38 phases by a solo developer using structured agentic workflows.
The Product
PropertyHQ is a modular SaaS platform where construction and property service businesses subscribe to trade-specific modules and get a complete job management system tailored to their trade. Any contractor can sign up, activate only the modules they need (Flip, Renovations, HVAC, or Plumbing), and immediately have scheduling, budgeting, invoicing, and task management built for how they actually work.
The platform includes Rex, an AI assistant with 17+ tools that can parse receipts, generate estimates, manage documents, answer budget questions, and create tasks — all with a confirm-before-acting pattern so data is never silently mutated. A customer portal lets end-clients view project timelines, approve invoices, and communicate with contractors through magic-link authentication.
Every line of the 82K LOC codebase was written through structured agentic development — Plan-Apply-Unify for features, GSD for research, and parallel agent teams for cross-module work. The project demonstrates what a single developer can ship when AI-assisted workflows are treated as a serious engineering discipline.
How It Was Built
PropertyHQ is the most complete demonstration of agentic development at scale. The project used a decision tree to route every task to the right workflow based on complexity, and parallel agent teams to ship cross-module features simultaneously.
Task Routing Decision Tree
Tiny — Direct Edit
Single-file typos, missing imports, config tweaks. No framework ceremony needed — just fix it.
Small — GSD Quick
2–3 file changes with well-understood scope. Fast execution tracked in STATE.md with atomic commits.
Medium — Paul (Plan-Apply-Unify)
Standard feature work. Every plan has YAML frontmatter, BDD acceptance criteria, file boundaries, and an autonomous flag. 160+ plans shipped this way.
Large — Paul + Research
Architectural changes preceded by GSD research phases. Deep codebase mapping before planning begins.
Parallel — Agent Teams
Cross-module features shipped by multiple agents simultaneously: module-parallel (same feature across Flip/Reno/HVAC/Plumbing), layer-parallel (data + UI in parallel), or investigation teams racing to root-cause issues.
Quality Gates
Medium and large features passed through additional verification layers. A Devil’s Advocate agent challenged assumptions during planning and reviewed implementations for edge cases. An Auditor agent verified acceptance criteria were met post-implementation. Pre-commit hooks enforced i18n parity across English and Spanish translations on every commit.
Every plan’s SUMMARY.md documented deviations from the original plan, auto-fixed issues, and decisions made with rationale — creating an audit trail that future sessions could reference for architectural context.
Modular by Design
Flip Module
Property flipping with portfolio management, budget tracking with 100+ cost code presets, transaction ledger, and task management with photo-required completion for construction verification.
Renovations Module
Client-based remodeling with estimates, selections management, change orders, and a complete invoice lifecycle (Draft → Sent → Paid) with Stripe Connect payment processing.
HVAC Module
Service and install jobs with scope builder, scheduling, and invoicing. Designed for HVAC contractors who need to manage both maintenance calls and larger installation projects.
Plumbing Module
Distinct job and customer models built for plumbing contractors, sharing the platform’s scheduling, invoicing, and task infrastructure while maintaining trade-specific workflows.
Cross-Module Features
Rex AI Assistant
17+ owner tools for receipt parsing, budget Q&A, task/vendor/client creation, estimate generation, and document management. 7 foreman tools for field work. Confirm-before-acting pattern, core memories, rate limiting, and org-scoped Zod validation.
Financial Pipeline
End-to-end invoicing with Stripe Connect (ACH + card), QuickBooks sync with AES-256 encrypted tokens and auto-refresh, public invoice approval pages, and estimate-to-invoice conversion across all modules.
Customer Portal
Magic-link authenticated portal where end-clients view project timelines, approve invoices, browse photo galleries, and message their contractor — all without creating an account.
Proactive Insights
18 owner insights and 5 foreman insights generated deterministically (zero LLM calls) — overdue tasks, budget overruns, stale jobs, worker overload, pipeline health, and expense spikes with i18n templates.