Senior Full-Stack Engineer for Large-Scale Migration Project

underpond Serbia
Remote
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AI Summary

Join UNDERPOND as a senior full-stack engineer to lead a large-scale migration project from a legacy PHP monolith to Next.js on AWS. Responsibilities include building Next.js routes, implementing session-based auth, and porting existing integrations. Key requirements include 2+ years of TypeScript/Node.js experience, strong Next.js skills, and hands-on AWS experience.

Key Highlights
Large-scale migration project from PHP to Next.js on AWS
Building Next.js routes and API handlers
Implementing session-based auth and porting existing integrations
Key Responsibilities
Build Next.js (App Router) routes and API handlers against the existing MySQL schema
Implement session-based auth (iron-session) with backward-compatible bcrypt password verification, plus Google/Apple OIDC
Port existing integrations from PHP to TypeScript
Write Vitest tests for business-critical logic
Help with AWS deployment (ECS Fargate, RDS MySQL, S3, SES, EventBridge, BullMQ on ElastiCache)
Technical Skills Required
TypeScript Node.js Next.js App Router Server Components Route Handlers SQL joins indexes query tuning AWS ECS RDS S3 GitHub Actions CI/CD Vitest Knex Zod bcrypt iron-session Google/Apple OIDC
Benefits & Perks
100% remote
Full-time / 40 hrs per week
Rate: DOE, send your expected rate
Nice to Have
PHP experience
Payment integration experience (Stripe, PayPal, Apple Pay)
AWS DMS or other database migration tooling

Job Description


UNDERPOND is a creative and technology studio focused on building modern digital products and scalable software systems.


We’re currently looking for a senior full-stack engineer to join a large-scale migration project.


Full-Stack Engineer


Legacy PHP → Next.js Migration


We're migrating a production web platform from a legacy PHP monolith to Next.js on AWS. Looking for a senior full-stack engineer to join the build.


This is migration work, not greenfield. The legacy app is large, hundreds of routes, ~100 MySQL tables, multiple third-party integrations (payments, email, SMS, external APIs). The goal is functional parity first, then incremental improvement.


What you'll do


● Build Next.js (App Router) routes and API handlers against the existing MySQL schema (Knex, Zod, no ORM in v1)

● Implement session-based auth (iron-session) with backward-compatible bcrypt password verification, plus Google/Apple OIDC

● Port existing integrations from PHP to TypeScript

● Write Vitest tests for business-critical logic

● Help with AWS deployment (ECS Fargate, RDS MySQL, S3, SES, EventBridge, BullMQ on ElastiCache)


Required


● 2+ years TypeScript / Node.js in production

● Strong Next.js (App Router, Server Components, Route Handlers)

● Solid SQL joins, indexes, query tuning on real data

● Hands-on AWS: ECS, RDS, S3, GitHub Actions CI/CD

● Comfortable reading legacy code and shipping in small, reversible slices

● Clear written English, async-friendly


Nice to have


● PHP experience (useful for reading the source app)

● Payment integration experience (Stripe, PayPal, Apple Pay)

● AWS DMS or other database migration tooling


Logistics


● 100% remote

● [Full-time / 40 hrs per week — adjust]

● Rate: DOE, send your expected rate


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