Construction management SaaS, own product

Obly

A construction management SaaS in production, used on the web and through the iOS app downloaded from the App Store. A NestJS API over PostgreSQL serves a Next.js web app and an Expo mobile app, sold by subscription in three plans and built spec first: the product intent lives in a documentation repository that precedes the code.

Role: Sole authorship: product, architecture and engineering across six repositories.
Period: 2026 to present
Status: In production, on the web and on the App Store

Obly dashboard comparing a project's budget against spend, with an S-curve and category concentration.

What the system does

A daily log captured on site, with photos taken on the spot and document scanning through the camera.
Per-project finance: budget by stage, expenses, supplier quotes and planned against spent.
Scheduling with a work breakdown structure, assisted setup and MS Project XML import.
A document library at the account level, holding designs, contracts, invoices and permits.
Floor-plan reading from PDF and budget import from spreadsheets, both through a language model, with mandatory review before anything is written.
A voice assistant that classifies what was said and turns it into an entry.
A construction report in PDF, assembled from what was already recorded.
Subscriber teams and client access, with permissions by role.
Subscription in three plans, with a fourteen-day trial and no card.

Architecture

A NestJS API over PostgreSQL holds the business rules, across twenty-seven modules and seventy-seven migrations. The Next.js web app and the Expo app consume the same domain model.
Isolation per contracting account: team, floor plans, storage and commercial rights live at the account level, not the user level. There is no separate account entity, the account is the owning user.
Authentication by a Firebase token verified on the server in a route guard. The backend stores no password, session or refresh token.
An entitlement engine on the server: a capability catalog, a per-plan template in a table, a capability guard on write routes and an atomic monthly reservation for the model import quota.
Library files in S3-compatible storage on Cloudflare R2, with signed URLs for upload and download. PostgreSQL holds the object key, and reconciliation of abandoned uploads runs once a day.
Floor plans in PDF rendered with mupdf and read by a Gemini model. The same provider serves budget import and the assistant's classifier, always with schema-validated output before anything is written.
Schedule import from MS Project XML and from spreadsheets. Import is always a preview: nothing enters the domain before confirmation.
Subscription billing with Stripe, with prices read from the provider and never copied into the database or the UI.
CI against a real PostgreSQL on GitHub Actions, migrations applied before deploy, and the daily cleanup routine scheduled in the same place.
A code-free documentation repository holds the product intent: a single PRD, one hundred and seventy-six business rules with a status across fifteen domains, six ADRs, feature specs with acceptance criteria, and two skills describing the change procedure.

Implementation details

No price is written into the database or the UI: the catalog is read from the payment provider on every request.
The billing webhook records the event before any mapping, and a partial unique index enforces one live subscription per account.
The mobile app does not sell: billing happens on the web, and the app only reads the entitlement in force.

Technologies

TypeScript: One language across the three application repositories.
NestJS: The API framework, with modules, guards and dependency injection.
TypeORM: ORM and the seventy-seven versioned migrations.
PostgreSQL: The product's single database.
Next.js: The authenticated web application.
React Native e Expo: The iOS and Android app, with file-based routing and delivery through EAS.
Firebase Auth: Identity on web and mobile, with the token verified on the server.
Stripe: Checkout, customer portal, subscription and webhook.
Cloudflare R2: Storage for photos, thumbnails and documents, with signed URLs.
Gemini: Floor-plan reading, budget import and the voice assistant's classifier.
mupdf: Rendering the PDF floor plan before the model reads it.
exceljs e fast-xml-parser: Reading the budget spreadsheet and the MS Project XML.
Zod: Validating model output before it becomes a write to the domain.
TanStack Query: Data caching and synchronization on the web.
Tailwind CSS: Styling for the web application.
Jest, Supertest e Vitest: Tests for the API, the web app and the mobile app.
Swagger: API documentation.
Expo Push: Notifications delivered by the API in batches, revoking invalid tokens.
PostHog: Product analytics in the mobile app.
GitHub Actions: CI against a real PostgreSQL and the daily cleanup routine.

The project schedule as a Gantt chart, grouped by stage, with bars for done, in progress and pending, and today's line.
MS Project XML import under review: three stages and ten activities detected, with item-by-item selection before anything is created.
Budget import through a language model, with the item list open for review before anything is written.
Daily log in the mobile app, with a photo taken on site.
The project document library, with folders for designs, contracts, invoices and permits.
Cover of the construction report generated for the client.

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