CT Cristian Trifan

Selectively taking new engagements

Full-stack engineering,
with agents in the loop.

I'm Cristian Trifan, a senior full-stack engineer working in React, TypeScript and Node. I build complex frontend systems and take features end to end, with tests behind them. Codex and Claude are part of that work every day, including on Frontend Mastery, the learning platform I build and run.

[email protected] LinkedIn GitHub

Calpe, Spain — remote across the EU

Cristian Trifan, with a React component, a system architecture diagram and an AI workflow rendered behind him.
  • Since 2005
  • TypeScript
  • React
  • Next.js
  • Node.js
  • Testing & CI/CD
  • Stripe
  • Codex
  • Claude
  • MCP

Approach

Agents write more of the code every month. Deciding what's worth writing is still the job.

I've worked in agentic workflows daily since they became genuinely useful — Codex for most of the building, Claude for review, MCP servers for context, agent skills for the parts that repeat. It changed how much ground I cover in a week. It didn't change who is accountable for what ships.

The agent handles

  • first-pass implementations
  • refactors spanning dozens of files
  • test scaffolding and fixtures
  • migrations and dependency bumps
  • wiring, boilerplate, glue code
  • the second, third and fourth attempt

I stay on

  • The architecture — and the constraints the agent works inside.
  • What done actually means for this feature.
  • The review. Every diff, before it lands.
  • The trade-offs I'd still defend in six months.

More surface covered per week, against the same bar for what reaches production.

Selected work

What I've built

2024 — present Own product

Frontend Mastery

Senior full-stack engineer — founder

A learning platform where frontend developers solve UI challenges in an embedded editor with live preview, publish their solutions, and build a public profile.

  • Built the architecture and every core system: editor, live preview, profiles, solutions, AI-powered feedback.
  • Implemented PRO memberships end to end — Stripe subscriptions, billing, and plan changes.
  • Evolve it daily with Codex, plus Claude for adversarial review and challenge generation; most of my agentic practice comes from this codebase.
  • Next.js
  • TypeScript
  • React
  • Node.js
  • Stripe
  • Codex
  • Claude
2024

Parloa

Senior React developer

Voice and AI workflow platform — provider integrations and the analytics surface.

  • Added ElevenLabs as a text-to-speech provider, and surfaced orchestrator errors in the UI so failures became diagnosable.
  • Integrated Preset.io into the analytics dashboard with authenticated embedding.
  • Expanded end-to-end coverage and moved the UI onto the in-house component library.
  • React
  • TypeScript
  • E2E testing
2021 — 2023

Wayfair

Senior React developer

Internal platform for EU shipping rate cards — pricing workflows and shipment cost estimation across regions.

  • Built the React platform for creating and managing rate cards.
  • Introduced unit and e2e testing plus CI/CD improvements, cutting regressions and raising release confidence.
  • React
  • TypeScript
  • CI/CD
2011 — 2017

Acunetix — Invicti

Senior frontend architect

Web vulnerability scanning, shipped both on-premise and as a cloud product.

  • Designed a decoupled frontend architecture serving on-prem and cloud from one codebase.
  • Added localization and configurability so product variants didn't fork the UI.
  • Earlier: built the subscription, licensing and recurring payments platform, integrating ERP and PayPal.
  • Frontend architecture
  • Localization
  • Billing

Clients

Teams I've worked with

  • Parloa
  • Wayfair
  • Acunetix
  • Equal Experts
  • Accesa
  • Essensys
  • Zenitech
  • M&M Computers
  • Ager Solutions

Contact

Selectively taking new engagements.

Remote contract work across the EU. If you have a platform to build, an architecture to untangle, or a team that wants to work well with agents — write to me.

[email protected]
LinkedIn GitHub Frontend Mastery