Senior Frontend Engineer

AleksandarTimić

Fifteen years of front ends and the systems behind them: engineering simulation, crypto lending, commerce, and now AI-search analytics at Semrush. Architecture, mentoring, and hands-on delivery, in that order of difficulty.

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01Profile

About

I build software people rely on, and the teams that ship it.

I have spent fifteen years building software people depend on: cloud engineering simulation, crypto lending, commerce for a consumer hardware company, and now AI-search analytics. Frontend engineering is the part I enjoy most, but I have worked across languages, backends, databases and infrastructure for long enough that I design against the whole system rather than the edge of it.

Alongside that I have led and mentored engineers, defined application architecture, and built and shipped full-stack products on my own while staying hands-on. More recently I have moved a lot of my attention to practical AI work: product features built on language models, retrieval-augmented generation, and agentic development workflows, the tooling side of which I now use daily.

15years
Building software people depend on
150+
Projects delivered in independent practice

02Career

Experience

2025 — PresentBelgrade

01 / 08

Semrush, an Adobe company

Senior Frontend Developer

AI-search analytics

Engineer AI-search analytics that turn prompt-level company and competitor mentions into visibility-gap analysis and actionable brand intelligence.
Shape production frontend with React, TypeScript, Astro, MobX, SCSS Modules, Intergalactic components, react-i18next, Crowdin and Valibot.
Design agentic development workflows with OpenAI Codex and Claude Code: custom skills, MCP integrations, context-aware tooling and reusable automation, covered by Jest and Playwright.

2022 — 2025Belgrade

02 / 08

Symphony.is

Software Engineer, Senior Frontend

Commerce, interaction and industrial software across client teams

Led and mentored 3 engineers across 2 projects.

Led and mentored three engineers across two projects, covering onboarding, pairing, code review, technical guidance and career development.
Engineered customer-facing solutions for Humane across Next.js, React, TypeScript, Shopify, Hydrogen, Liquid, GraphQL/gRPC and Vercel.
Solved interaction-heavy frontend problems with Three.js, TanStack Query, React Hook Form, React Virtual, React Spring, Radix UI and Panda CSS.
Established reusable, testable UI patterns with Storybook, Jest, React Testing Library, Yup and Zod, improving consistency across releases.
Built software for the Swedish wood industry with React, TypeScript, TanStack Query, Material UI and Sass, including service worker and charting functionality, with containerized delivery through Docker and Azure DevOps.

2021 — 2022Belgrade

03 / 08

Celsius

Senior Frontend Developer

Crypto lending and borrowing at consumer scale

Built core experiences for the Celsius lending and borrowing application with React, TypeScript, TanStack Query, Node.js, Material UI, Emotion and styled-components.
Strengthened UI quality through reusable Storybook components, Jest, React Testing Library, close Figma collaboration and disciplined delivery.
Advanced scalable frontend delivery and controlled experimentation with LaunchDarkly, Optimizely, Docker, Lerna and jscodeshift.

2015 — 2021Munich

04 / 08

SimScale GmbH

Senior Frontend Developer

Cloud computer-aided engineering

Six years on one product, the longest stretch here.

Helped evolve the frontend of SimScale's cloud computer-aided engineering platform across six years, using React, Backbone.js, JavaScript and Sass, including sustained migration away from legacy technologies.
Applied full-stack delivery across PHP, MySQL, Docker, Vagrant, Jenkins, Git, Bash, Grunt and Gulp to ship and sustain a complex global engineering product.

2014 — 2015Belgrade

05 / 08

Deploy Inc.

Senior Frontend Developer

Advertising platform and HTML5 games

Built an advertising platform and HTML5 games with JavaScript, jQuery, Phaser, Sass, Handlebars, Grunt and Jenkins.
Integrated Amazon CloudFront, Google Analytics and Google DFP into production advertising workflows.

2012 — 2014Belgrade

06 / 08

Qode Interactive

Frontend Developer

National Lottery of Serbia

Built the frontend for Serbia's National Lottery and a related charity campaign, including two reusable JavaScript parallax engines, with HTML5, CSS3, Sass, jQuery and Git.

2010 — 2012Belgrade

07 / 08

WhiteCitySoft

WordPress Developer

Themes and plugins for international clients

Developed custom WordPress themes and plugins for international clients including Reebok and Mercy Drink, using PHP, MySQL, JavaScript, jQuery, HTML and CSS preprocessors.

2007 — PresentSerbia

08 / 08

Altimcode

Independent practice

150+ projects, including work for LG and BlackBerry

Operate an independent web development practice focused on websites, WordPress themes and plugins, with more than 150 projects delivered, including work for LG and BlackBerry.
Led frontend performance and quality optimization across production websites, reaching 100/100 Google Lighthouse scores in Performance, Accessibility, Best Practices and SEO.

03Stack

Skills

Everything that has been used in production or carried far enough to be worth naming: 148 entries across 15 disciplines.

React ecosystem

React
TypeScript
JavaScript
Vanilla JavaScript
Next.js
Astro.js
Remix
TanStack Query
TanStack Router
TanStack Table
React Router
React Hook Form
React Virtual
Formik
Zod
Yup
Valibot
Service workers

AI engineering & automation

Vercel AI SDK
Codex
Claude Code
Cursor
Custom skills and plugins
MCP servers
Retrieval-Augmented Generation
Agentic workflows
Embeddings
Ollama
n8n

Leadership & architecture

Team leadership
Developer mentoring
Onboarding
Pairing
Code reviews
Career development
Application architecture
Frontend performance

Backend & databases

Node.js
PHP
Python
PostgreSQL
pgvector
Neon
MySQL
SQLite
Prisma ORM
GraphQL
GROQ
gRPC
WebSockets
Socket.IO
NATS.io
NextAuth
OAuth 2.0
JWT
Paddle
Resend

CSS

HTML5
CSS3
Sass
Less
Panda CSS
styled-components
Emotion
CSS Modules

State management

MobX
Redux
Zustand
Jotai
React Context

Testing

Jest
React Testing Library
Playwright
Cypress
Percy.io

CI/CD & DevOps

Git
GitHub
GitHub Actions
Vercel
Docker
Jenkins
Vagrant
Azure DevOps
Linux
Bash
Vite
Webpack
Lerna
jscodeshift
Grunt
Gulp
SVN
Amazon CloudFront

Design systems

Storybook
Figma
Mantine
Material UI
Chakra UI
Radix UI
Intergalactic

Performance

Core Web Vitals
Google Lighthouse
Search engine optimization

Creative & interactive

Three.js
React Three Fiber
Drei
React Spring
Motion
WebGL
GLSL / custom shaders
GSAP
Recharts
Chart.js
ECharts

Shopify

Shopify
Hydrogen
Shopify Extensions API
Liquid

Web3

Ethers
MeshJS
Wagmi
WalletConnect
Web3Auth
MetaMask
Nami
Eternl

CMS

Sanity
Contentful
WordPress
WooCommerce
Jekyll

Other

i18next
Lingui
Crowdin
LaunchDarkly
Optimizely
Google Analytics
Google DFP
jQuery
Underscore.js
Handlebars
RequireJS
Browserify
Jira
ClickUp
Trello
Photoshop
Illustrator

04Credentials

Education

Belgrade, Serbia

Master of Science, Mathematics and Informatics

University of Belgrade, Faculty of Mathematics

Mathematics first, software second, which is why I reach for the model of a problem before the framework for it.

Belgrade, Serbia

Electrical Technician for Computers

Nikola Tesla Electrotechnical High School

Where the hardware underneath stopped being an abstraction.

Languages

SerbianNative
EnglishFull professional proficiency

References

His extensive knowledge in React, TypeScript and other frontend technologies distinguishes him as a true leader in frontend development. He effortlessly applies these skills to transform intricate designs into functional and engaging digital experiences. What sets Aleksandar apart is his intrinsic research ability. He actively keeps abreast of new developments and techniques, translating insights into actionable strategies for the team.
Pepe Blasco Nunez de CelaCTO, DeFi protocol
Aleksandar is one of the rare developers who are capable to produce quality work with such precision and dedication. Very demanding when it comes to details and skilled in multi-level environments, never refused challenge when he is confident he will succeed. Truly valuable member of our team.
Gordan TopalovićCEO at WhiteCitySoft
Alex produces highly functional, clean code and can deliver even the most complex tasks in a timely manner.
Timothy McMillanOwner at McMillan Freelance

05Contact

Let’s talk.

I am at Semrush and happily busy, but always glad to hear about interesting architecture, a team that needs building, or a hard frontend problem. Email is the fastest route.

aleksandartimic@gmail.com