Software Engineer (Full-stack)

Kongi; Northern (KY); On-site; USD 90,000 - 150,000; Full time

Job summary

Kongi is hiring a full-stack engineer with a backend-centric focus to build and scale the marketplace. You’ll own the catalog, search, recommendations, checkout, and ads infrastructure, shipping features from API to app and web within weeks.

You will drive reliability, performance, and money-handling correctness, while collaborating with founders and small teams across the product. Expect rapid iteration and end-to-end ownership.

Qualifications

• 4+ years building backend systems for a product people use, or 2+ as an early engineer at a startup.
• Fluency in at least one major programming language.
• Real database fluency: schema design, constraints and transactions, migrations as files, indexes you can explain.
• Care with money and correctness: idempotency, retries and reconciling against a payment provider.
• Track record of owning things end to end at a startup or small team, not just a slice of a big codebase.
• Product instinct: you notice what a change means for shoppers and brands, not just the code.
• Clear communication: you name tradeoffs, ask questions and stay low-ego when corrected.

Responsibilities

• Build the marketplace end to end across API, app and web.
• Keep the catalog in sync with brands' stores: prices, stock, options and photos.
• Build checkout, payments, refunds and the credit ledger for accuracy.
• Improve search and recommendations with embeddings and ranking.
• Make every screen feel instant, with caching and fast loads.
• Own deploys, tests and monitoring to ship daily without breaking things.
• Keep ads auctions and budgets accurate and hard to game.

Skills

Backend development

API design

Database design

Distributed systems

Code quality

Education

Bachelor's degree in CS

Tools

PostgreSQL

Redis

Git

Docker

Job description

The role

We're hiring a full-stack engineer to build Kongi with the founding team. Your center of gravity is the backend: the catalog, search and recommendations, checkout and payments, and the ads that pay shoppers.

You'll work across the app, the web shop and everything behind them. What you build is in shoppers' hands the same week.

What you'll do

Build the marketplace

• Ship features end to end with the founders, from the API to the app and the web.
• Keep the catalog in sync with thousands of brands' stores: prices, stock, options and photos.
• Build checkout, payments, refunds and the credit ledger so the money is always right.

Make it fast and personal

• Improve search and recommendations: embeddings, ranking and the feeds shoppers open every day.
• Make every screen feel instant, from the queries to the caching to what loads first.

Own reliability

• Own deploys, tests and monitoring, so we ship every day without breaking things.
• Keep the ads auction, budgets and credit accurate and hard to game.

What we're looking for

• 4+ years building backend systems for a product people use, or 2+ as an early engineer at a startup.
• Fluency in at least one major programming language.
• Real database fluency: schema design, constraints and transactions in the database, migrations as files, and indexes you can explain.
• Care with money and correctness: idempotency, retries and reconciling against a payment provider.
• A track record of owning things end to end at a startup or small team, not just a slice of a big codebase.
• Product instinct: you notice what a change means for shoppers and brands, not just the code.
• Clear communication: you name tradeoffs, ask questions and stay low-ego when corrected.

Bonus points

• Search or recommendation systems.
• Payments or marketplace experience.
• iOS development.
• Ads, auctions or fraud detection.
• Side projects or open source that people actually use.

What success looks like

• Features shipped every week, with tests, and very little breaking.
• Faster pages and feeds, measured.
• A catalog that stays right as we add brands.
• Payments and credit that reconcile to the cent.

About you

You like small teams and big ownership. You'd rather read the logs than guess, you care about the details shoppers never see, and you're happiest when something you built gets used the same day.