TS.Tomislav Sertić

Software engineer · Zagreb, Croatia

Tomislav
Sertić.

Building software for
complex business environments.

Software engineer with multi-year experience in enterprise backend and full-stack development. Building business logic, APIs, React interfaces and SQL integrations for international client projects, with hands-on involvement from requirements through production delivery.

Get in touch View experience

Selected client project experience

UBSUniversity of
LuxembourgCURIAESASaudi AramcoTHT

01 / Experience

Engineering in an
enterprise context.

Software Engineer / Backend & full-stack

Enterprise platforms & international client projects

My professional work centres on Java, JavaScript, React, SQL and Archibus, an integrated workplace management platform. I translate operational requirements into application features, backend workflows and integrations that fit established business systems.

I investigate issues across the application stack, implement changes in existing codebases and work with project teams through testing and production releases. This includes Git and Bitbucket workflows, Jira issue tracking, remote servers and coordination across development, test and production environments.

Responsibilities & delivery

  • Develop Java business logic, scheduled workflows and application integrations.
  • Build and maintain React and JavaScript interfaces connected to enterprise backends.
  • Write SQL queries, stored procedures and database updates; investigate data and performance issues.
  • Diagnose defects across frontend, backend and database layers, and document changes for testing and release.
  • Collaborate with international project teams and communicate technical findings, dependencies and implementation decisions.

Selected client engagements

Additional project experience includes the European Space Agency (ESA), Saudi Aramco and THT.

Client names describe project experience, not direct employment or endorsement. Proprietary implementation details are not published.

02 / Expertise

Across the stack.
Close to the details.

A connected skill set for building, integrating and supporting business applications.

01

Backend services & APIs

Java business logic and enterprise workflows, complemented by Node.js and Express for web services and REST API development. Connecting applications and data while keeping interfaces and business rules clear.

JavaNode.jsExpressREST APIsArchibus
02

Frontend & user workflows

JavaScript and React interfaces for business users. Integrating modern frontend components into enterprise applications, with additional web development using Next.js and TypeScript.

JavaScriptReactNext.jsTypeScriptHTML / CSS
03

Databases & data integration

SQL queries, stored procedures and database changes that support application behaviour. Working with relational data, troubleshooting issues and improving query performance.

SQLRelational databasesStored procedures
04

Environments & delivery

Git-based collaboration and releases across test and production environments. Practical local environment work with Linux/WSL2, Docker and Docker Compose, including containerised application and database services.

Git / BitbucketJira / AtlassianLinux / WSL2DockerDocker Compose

Continuing technical development

C# / .NET, Unity & AI integration

Alongside my enterprise work, I’m developing my C# and .NET skills through independent learning, practising C# scripting in Unity, and exploring AI model integration in web applications. I’m interested in backend roles that combine systems integration with opportunities to grow into real-time and 3D applications.

Independent learning and experimentation alongside my professional Java / React / SQL work.

03 / Approach

More than the
code in front of me.

Understand the business context

Connect technical requirements to the people, processes and existing systems the application needs to support.

Work with the system as a whole

Trace behaviour across frontend, backend and database layers to resolve issues and make changes that fit the wider application.

Carry changes through delivery

Collaborate with project teams, document changes and work through testing and release processes with production stability in mind.

04 / Contact

Let’s talk engineering.

For professional opportunities and project conversations.

tsertic5@gmail.com

Find me online