Founder & Engineer · Yogyakarta, UTC+7
I build reliable websites, marketing technology, and AI-native systems.
75+ websites built and conversion tracking systems deployed for agencies and businesses across Germany and international markets.
- Google Tag Manager
- Google Analytics 4
- Consent Mode V2
- Google Ads conversions
- Server-side tagging
- Data layer design
- Technical SEO
- WordPress
- Next.js
- Cloudflare
- AWS
- AI-native development
Selected Work
Anonymised case studies from tracking, consent and conversion projects.
- Privacy-First Tracking for a German Dental Practice Consent & tracking · Healthcare
- Consent and Conversion Tracking for a Moving Company Consent & conversions · Moving
- Repairing the Tracking Chain for a Yoga School Tracking audit · Yoga education
- Tracking Standards for a Performance Marketing Agency Event standards · Agency
In Numbers
- 75 +
- Websites built and maintained
- 350 +
- Clients served since 2020
- 2018
- Building for the web since
Overview
I'm Sultan Kautsar, a Founder & Engineer focused on web engineering, marketing technology, and AI-native development.
I build reliable digital systems across websites, infrastructure, analytics, tracking, automation, and marketing tools.
I choose technology based on the problem and the desired outcome, with a focus on simplicity, reliability, and efficient execution. AI is an active part of my engineering workflow for research, development, debugging, automation, and system design.
More about meCurrently
- Marketing Technology Engineer MediaConversion, Hamburg
- Software Engineer FlexyPack, Jakarta
- Founder & Engineer Rayatiga
Recent Notes
Things I've learned building, measuring and shipping, written down so they stay useful.
- Two Servers, 50 Sites, One Bug
How wp2shell, a WordPress Core exploit, reached about 30 old WordPress sites across two RunCloud servers, what the attacker left behind, how I cleaned up and contained it, and the hardening I now recommend.
- Cleaning Up a wp2shell Compromise
How an unauthenticated WordPress Core exploit spread across seven sites on one RunCloud server, the signs it leaves behind, the cleanup recipe I repeated on each site, and the changes that stop it from happening again.
- How This Site Is Tracked
How sultankautsar.com is tracked: a hand-built consent banner, Consent Mode V2 in advanced mode, Google Tag Manager, six GA4 events, and a Content Security Policy that only allows Google's tag domains.
- Working with Opus 5.5
How I use Claude Opus 5.5 in Claude Code for client work, company projects, and personal tools: the habits, the review loop, and what nine days of real sessions looked like.
Next step
Have a project in mind? Let's talk.
Tell me what you have and what you need. I'll usually reply within one working day with how I'd approach it.