Subi: Engineering an AI Transaction Coordinator
Client: Subi, a proactive AI transaction system for real estate agents, transaction coordinators, and brokerages Our role: Embedded product engineering partner Scope: Backend, web, mobile, AI and document intelligence, browser automation, infrastructure, brand graphics
About Subi
Subi is a transaction genie for real estate. Instead of giving agents another dashboard to manage, it completes the work: it drafts and sends emails and texts when they are needed, watches every contractual deadline, organizes documents and links them to the right parties, keeps files audit-ready against the brokerage's rules, and coordinates buyers, sellers, lenders, and inspectors.
The Challenge
A product that acts on a live deal has a higher bar than one that only displays information. The AI has to read real purchase agreements accurately, in every state's format. It has to connect to the email, calendar, CRM, and transaction systems agents already use, many of which have no API. And it has to be dependable enough that a missed deadline never traces back to the software. Subi needed senior engineering capacity across the whole product at once, not on a single feature.
What We Did
AW3 Technology works inside Subi's engineering team and ships to production continuously alongside its in-house engineers, across all four of the platform's codebases.
- Core API: the Rails backend behind transactions, deadlines, messaging, billing, and integrations with email, calendar, and CRM tools
- Web app: the Next.js application agents work in every day, covering transactions, chat, calendar, contacts, documents, forms, tasks, and team and compliance settings
- Mobile app: the Expo app for iOS and Android, including sign-in, theming, and App Store readiness
- Document intelligence: the pipeline that extracts dates, parties, and terms from purchase agreements across US states, using several AI models with automatic fallback and OCR
- AI agent: the assistant that reviews contracts, classifies clauses, catches struck-through terms, and prepares the next action
- Browser automation: a cloud browser agent and a Chrome extension that sign in to third-party real estate systems and complete the data entry there, so agents do not have to re-key a deal
- Reliability and security: security, performance, and production audits, a stabilization sweep, QA scenario runs, and deployment runbooks
- Brand graphics: a set of 3D logo, icon, and hero illustrations for the product and marketing site
How We Work
The engagement runs like an in-house team. Work is planned with Subi's engineers, reviewed through pull requests, tested against written agent-flow scenarios, and summarized in monthly engagement reports that list what shipped across each repository.
Outcome
Subi is live at oksubi.com on web and mobile. AW3 continues as an embedded engineering partner, with more than a thousand commits landed across the API, the apps, the document pipeline, and the browser automation tooling.
Stack
Ruby on Rails, PostgreSQL with vector search, Next.js, React Native (Expo), Python (FastAPI), Anthropic, OpenAI and Gemini models, AWS, Render, and Firebase.
