Skip to content
Yellow Frog Development

Services

Senior software engineering, from architecture to production.

I'm Nedžad Hamzić, the engineer behind Yellow Frog Development. For more than ten years I've built software products for teams in fintech, health tech, real estate and AI: from system design and APIs to web apps, AI features and mobile games.

Start a projectLinkedIn
shipping software
10+ yearsshipping software
live on iOS and Android
2 gameslive on iOS and Android
teams I've worked with
EU · UK · USteams I've worked with
overlap with US Eastern time
6 hoursoverlap with US Eastern time

What I do

  • Product engineering

    Features built end to end: backend-strong, with the front end to match. Solid APIs and data models underneath, Next.js and React on top.

  • AI features & platforms

    Putting AI into real products: LLM and media-generation pipelines across several providers (OpenAI, Anthropic, Google Vertex and others), MCP, and the reliability and cost control production needs.

  • Architecture & technical ownership

    System design, cloud architecture and design reviews. Taking greenfield products from a blank page to production, and owning them once they're live.

  • Backend, cloud & data

    Node.js and TypeScript first, plus Go, Java and Scala. Microservices, event-driven and serverless systems on AWS, Azure and GCP, with Terraform and Pulumi.

  • Payments & billing

    Stripe subscriptions and billing flows, bank and payment-provider integrations, recurring payments.

  • Mobile apps & games

    From idea to release on iOS and Android, including ads, privacy and store listings. The studio's own games are the proof.

    See the games →

Products I’ve worked on

  • A European real-estate group: a serverless contract and subscription platform across several markets
  • An AI media creation platform: the multi-provider generation pipeline, Stripe billing and the model picker in the web studio
  • An industrial AI asset-management platform: real-time data pipelines and enterprise integrations
  • A communication platform for seniors and care homes: microservices and cloud functions
  • A US savings app: APIs, bank integrations, recurring payments and round-ups
  • Digital-health and community startups: platforms taken from zero to production as the sole backend engineer
  • Yellow Frog's own games: designed, built, released and supported end to end

Full work history on LinkedIn; CV on request.

Ways to work together

  • ProjectA feature or a whole product, built end to end with a clear scope.
  • Embedded senior engineerPart-time or full-time contract inside your team: your repositories, your process, your stand-ups.
  • Architecture & AI advisoryDesign reviews, choosing an approach, or a second opinion before you commit.

Remote, in English. Invoiced through Yellow Frog Development (sole proprietorship, Bosnia and Herzegovina).

Tools I use

  • TypeScript
  • Node.js
  • NestJS
  • Go
  • Java
  • Spring Boot
  • Scala
  • Next.js
  • React
  • tRPC
  • Tailwind
  • PostgreSQL
  • MySQL
  • DynamoDB
  • MongoDB
  • Redis
  • Kafka
  • AWS
  • Azure
  • GCP
  • Terraform
  • Docker
  • Kubernetes
  • Stripe
  • OpenAI
  • Anthropic
  • Google Vertex
  • MCP
  • Godot
  • GDScript

Have a project in mind?

Tell me what you’re building, where you are now and what you need. I’ll reply with whether and how I can help.

Start a projectLinkedIn