Domagoj Puljic

Domagoj Puljic

Backend Engineer

Available for workZurich, Switzerland

Backend engineer building systems that just work.

I like backend systems best when nobody has to think about them — the API responds, the pipeline runs, the deploy just works. 5+ years of making that boring reliability happen with FastAPI, PostgreSQL, Docker, and AWS — with quantified cost and reliability wins to show for it.

PythonFastAPIPostgreSQLDockerREST API design

Open to freelance backend/API projects and full-time mid-senior roles in Switzerland.

Swiss Permit B holder — no sponsorship required.

By the numbers

Every figure here traces back to a case study below — no vanity metrics.

5+

Years of backend engineering experience

career total

6

Production case studies delivered

this page

40%

Faster deployments after a monolith-to-microservices migration

INTIS

$100k/yr

Cut from infrastructure spend by replacing a vendor gateway

SeekandHit
Currently shipping withPythonFastAPIPostgreSQLDockerREST API design

Depth by category

Bars indicate hands-on proficiency, from foundation to production-level — not a badge collection.

Backend Engineering

  • Python
  • FastAPI
  • REST API design
  • Service integration
  • Authentication (JWT/OAuth)
  • Django
  • Flask
  • Monolithic architectures
  • Celery
  • Microservices architectures
  • API gateway / proxies
  • System design

Cloud & Infrastructure

  • Docker & containerization
  • CI/CD (GitHub Actions)
  • Environment configuration
  • Cloud deployments
  • AWS (IAM, S3, EC2, Cognito)
  • Jenkins
  • Kubernetes

Reliability & Operations

  • Performance optimization
  • Automated testing (pytest)
  • CI pipeline optimization
  • Service monitoring & observability
  • Incident investigation
  • Production debugging

Data & Storage

  • PostgreSQL
  • SQL & query optimization
  • Data modeling & schema design
  • ORM usage (Django ORM, SQLAlchemy)
  • Database migrations (Alembic)
  • Indexing & performance tuning
  • Redis
  • MongoDB
  • Firebase

Tools & Workflow

  • Git
  • Jira
  • Agile / Scrum
  • Code reviews
  • API documentation
  • Versioned API design
  • Postman / API testing tools
  • Linux command line

Frontend

  • Frontend-backend integration
  • JavaScript
  • Next.js
  • Vue.js

Work

Six roles, six different problems — the same pattern: find what's slow, fragile, or expensive, and fix it.

Took a Master's thesis prototype to a live, self-hosted production app — real-time market data across three purpose-fit databases.

Financial Dashboard — Full-Stack Fintech Platform

Personal project

Financial Dashboard is a portfolio-tracking and investing platform I built for my Master's thesis and then kept running as a real production app rather than letting it die in a repo. Users track holdings, compare performance against benchmarks, and pull live pricing without leaving the dashboard.

PythonFlaskVue 3PostgreSQLRedisMongoDBRender

Shipped production sites for two clients with automated CI/CD to Vercel, while building a FastAPI + PostgreSQL job-tracking platform to keep AWS and applied-AI skills current.

Freelance — Client Platforms & Personal Infrastructure

FreelanceJul 2025 – Present

Since mid-2025 I've worked as an independent backend/full-stack engineer, splitting time between client delivery and a personal engineering project used to stay sharp on production-grade Python and cloud practices.

PythonFastAPIPostgreSQLDockerGitHub ActionsVercelAWS

Cut incident resolution time by 30% through improved service observability and structured error handling.

Eturnity — Energy Simulation Platform

EmployeeNov 2023 – Jun 2025

Eturnity builds software for solar energy planning and simulation. I worked as a backend engineer building and maintaining Django services that powered energy calculation pipelines and internal tooling used by the operations and sales teams.

PythonDjangoPostgreSQLDockerAWS

Improved deployment speed by 40% by leading containerisation and breaking a monolith into independently deployable services.

INTIS — Microservices Migration

EmployeeAug 2021 – Nov 2023

INTIS operated a Django monolith that had grown to the point where individual team deployments were blocked by unrelated changes. I led the containerisation effort and drove the architectural migration toward FastAPI-based microservices, enabling teams to ship independently.

PythonDjangoFastAPIDockerPostgreSQLCI/CD

Eliminated $100k/year in Apigee licensing costs by replacing the vendor API gateway with an in-house FastAPI proxy and auth system.

SeekandHit — API Infrastructure Overhaul

EmployeeDec 2018 – Jul 2021

SeekandHit's API traffic was routed through Apigee, which had become the largest line item in their infrastructure budget without providing commensurate value. I designed and built a replacement API proxy in FastAPI, covering routing, rate limiting, and request transformation — removing the Apigee dependency entirely.

PythonFastAPIPostgreSQLDockerAWSOAuth2

Delivered a working protocol-mapping tool used by network engineers to translate between vendor-specific XML schemas.

Ericsson — Protocol Mapping Tool

InternshipJul 2018 – Sep 2018

During an internship at Ericsson, I built a protocol-mapping tool for network engineers who needed to translate data between different vendor XML schemas — a process that was previously manual and error-prone.

PythonNode.jsReactMongoDBXML

Get in touch

I am available for freelance backend and API projects, as well as full-time mid-senior backend and cloud engineering roles in Switzerland. Swiss Permit B — no sponsorship needed.

My process is straightforward: a short scoping call, a clear estimate, then regular updates until it ships — no surprises at invoice time.

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