Full Stack Engineer

What you'll do

Work across the full stack — data model, API contract, UI, and production behavior — contributing to domains as they move onto the modern stack.
Recognize bad legacy patterns and don't repeat them — read the existing Express/MongoDB and Backbone/React layers, understand where they fell short, and apply better practices in new development rather than carrying old habits forward.
Design for scale within real constraints — build solutions that scale even when they have to integrate with a rigid legacy system that can't be changed wholesale.
Build on the modern stack — NestJS modules (DI, guards, interceptors) and Next.js apps (App Router, server components, typed clients).
Understand the strangler-fig approach — how legacy and new run side by side, behind feature flags, with zero data loss and no downtime — and contribute to it without disrupting it.
Model relational data carefully — help move money-bearing/transactional data from documents into a normalized SQL schema with real constraints and safe migrations.
Write tests as a default — unit, integration, E2E. The suite is what lets the team move fast safely.
Spot and flag problems — the flaky test, the N+1, the missing index. Raise them clearly so they get prioritized, and pick them up when it makes sense.
Use AI tooling efficiently while understanding and standing behind every line that lands.

Requirements
4+ years shipping production full-stack
Strong TypeScript front and back
NestJS (or deep Express/Fastify w/ DI grasp)
Next.js/React (hooks, App Router, SSR/CSR)
PostgreSQL or MySQL (schema, indexing, transactions, migrations)
An eye for distinguishing good patterns from bad legacy ones
Ability to design scalable solutions that fit within an existing, rigid system
Testing discipline (Jest, Playwright/Cypress, Supertest)
API design (REST, auth, backward-compatible evolution)
Bonus:

Experience migrating off a legacy code
Fintech/payments/ledger
Message queues (RabbitMQ/SQS/Kafka)
MongoDB/Mongoose Aggregation
AWS/Docker/Kubernetes/CI
Deliberate AI-agent use in production workflows
Who you are:

Takes ownership and responsibility for their work
Eager to take initiative and grow
Has the judgment to spot bad legacy code and the discipline to not repeat it in new work
Designs for scale even inside rigid constraints
Refactors and builds with better practices rather than carrying old patterns forward
Moves carefully without breaking trust (tests + small PRs + flags)
Communicates trade-offs clearly
Raises issues and flags risks rather than routing around them

Benefits
ClassWallet is a positive, family-oriented team environment. Our focus is on encouragement, positive reinforcement, and gratitude. We work hard and are highly motivated to win but with a healthy perspective on life.

We offer an excellent salary and benefits commensurate with experience.

ClassWallet.com is proud to be an Equal Opportunity Employer. Applicants are considered for all positions without regard to race, color, religion, sex, national origin, age, disability, sexual orientation, marital or veteran status.

Skills Required
4+ years shipping production full-stack
Strong TypeScript front and back
NestJS (or deep Express/Fastify with DI grasp)
Next.js/React (hooks, App Router, SSR/CSR)
PostgreSQL or MySQL (schema design, indexing, transactions, migrations)
Testing discipline (Jest, Playwright/Cypress, Supertest)
API design (REST, auth, backward-compatible evolution)
Ability to recognize and avoid bad legacy patterns
Ability to design scalable solutions that fit within an existing rigid system
Experience migrating off a legacy codebase
Fintech/payments/ledger experience
Message queues (RabbitMQ/SQS/Kafka)
MongoDB/Mongoose aggregation experience
AWS, Docker, Kubernetes, CI experience
Deliberate AI-agent use in production workflows