Proof point → Given a financial-system spec, I shipped the API, the tests, the observability, and a deployed documentation site - because in finance, undocumented is unfinished.

🩻 Problem

Financial systems are unforgiving: money moves, roles gate who can move it, and every operation needs an audit-grade trail. The brief: implement core components of a financial system against a written requirements spec.

🔨 Solution

Jekomo - a NestJS 10 backend modeling the financial core:

Architecture Overview

  1. Domain models - users, accounts, and transactions over Mongoose/MongoDB.
  2. Security - Passport-JWT strategy plus role-based access implemented properly: a custom roles decorator and guard, including an admin role-change endpoint.
  3. Correctness scaffolding - DTOs with class-validator, a global exception filter, and the requirements (REQUIREMENTS.md) and route map (ROUTES.md) committed beside the code.
  4. Observability - Sentry middleware (with sourcemap upload) and Loggly structured logging from day one.
  5. Documentation as a deliverable - a TypeDoc-generated reference for every class, enum, and interface, custom-themed and deployed to its own public site on Vercel.

Quality signals

  • Unit tests (jest + jest-mock-extended + sinon) and an e2e suite, with coverage scripts.
  • ESLint + Prettier, typedoc.json - a complete, conventional toolchain.

📜 Philosophy

Treat every brief like a product. The spec goes in the repo, the routes are documented, the docs are deployed, and observability is wired before the first request - the habits that make financial software trustworthy.

🎓 Key learnings

  • NestJS idioms at depth: modules, guards, decorators, DTO validation, exception filters.
  • Modeling account/transaction domains with role-gated operations.
  • Documentation pipelines: code → TypeDoc → standalone deployed reference.

📈 Output & impact

  • A complete financial-system API with tests, deployed docs, and observability - the repo earned a fork and a star as a reference implementation.

🌍 Why this matters

Access to Capital · Trust, Security & Compliance. Funds, credit schemes, and grant programs all run on the same plumbing: accounts, transactions, role-gated approvals, audit trails. Whoever operates money at scale needs that plumbing built by someone who documents it well enough to be audited - and tests it before the first transfer.

🚀 Hire me

Building a system where money moves and roles matter? Let’s talk → · See also: The Investor Directory · The thesis