Software systems architect. Chief Technology Officer. Twenty-seven years of keeping things running.
Ishan Karunaratne is a software systems architect and Chief Technology Officer with more than two decades designing, building, and running production software, Linux systems, and DevOps infrastructure. He is CTO at Rehab Media Group, a US Army veteran who deployed to Iraq for Operation Iraqi Freedom, the writer behind TechEarl, and the sole developer of DNS Checker.
I was pulling systems apart to see how they broke long before anyone paid me to build them.
Professionally that is twenty-seven years now: networks, then servers, then databases, then architecture, then teams, and lately AI. The shape keeps changing and the underlying question never does, which is what happens when this breaks and who finds out first. I still write code most weeks, because a technology leader who has not touched the stack in three years is guessing, and the team can always tell.
I design the shape of a system before anyone writes code: data model, failure modes, where the load lands, what happens at 3am when a dependency goes away. Then I stay close enough to the implementation to find out whether the design survived contact with reality.
Technical strategy, hiring, and delivery, including M&A integrations and cloud migrations. I have taken teams through the unglamorous part, where two companies' systems have to become one without anybody's customers noticing.
I came up reverse engineering and debugging at the instruction level, fascinated by how things break. That lens never left. Security is part of the architecture, decided early, not a hardening pass bolted on the week before launch.
LLM applications, retrieval-augmented generation, agents, and the evaluation harnesses that catch regressions before users do. The interesting question is rarely whether a model can do something. It is whether the output is reliable enough to put in front of a customer.
Designed, written, and operated solo · dnschkr.com
A domain intelligence platform that analyzes more than 240 million domains a day. I own every layer: ingestion, the Elasticsearch index, the API, the front end, and the servers it runs on. Nobody else has ever had a commit in it, which is either a good sign or a warning, depending on your view of bus factor.
790+ articles, single author
Field notes on shipping real systems, written from work that went to production rather than from tutorials. The bulk is WordPress, Linux, DevOps, and application security, roughly 130 pieces each, then databases, JavaScript, CSS, AI engineering, and regex.
Privacy-first comment system
Threaded comments, reactions, and star ratings you embed with one script tag, funded by subscriptions instead of by watching the people reading your site. AI moderation, a REST API, and TypeScript SDKs.
51 states and DC, 8 practice areas
An independent attorney directory built on state bar records rather than paid placement. No firm owns it and nobody can buy a better position in the listings.
Sinhala song lyrics archive
Sri Lankan music is badly served online, so I built the archive I wanted to exist. Thousands of Sinhala lyrics, searchable, with no popups between you and the words.
Guitar chords and tabs
The companion to the lyrics archive: chords and tabs for Sinhala songs, for the people actually trying to play them rather than just read along.
19 varieties, caffeine data, and a joke
Half the fun of this one is the joke and the other half is real. It catalogues every Dr Pepper variety with the caffeine and nutrition numbers, and takes the caffeine-dependence part more seriously than the name suggests.
Code paste for WordPress developers
A paste bin that knows what it is looking at. PHP and JavaScript syntax highlighting, and every WordPress function and hook in your snippet auto-linked to its documentation.
Single-purpose encoder
Paste text in, get Base64 out. Nothing else on the page, no account, and no step between arriving and having the answer.
Single-purpose decoder
The other direction, on its own domain rather than as a tab on the encoder, because that is how people actually search for it.
2021 – now
Rehab Media Group
Technical strategy and architecture. Engineering culture, hiring, delivery, and the integration work behind acquisitions.
2020 – 2021
Rehab Media Group
Supported a 250%+ month-over-month revenue increase inside the first six months, and introduced the CI/CD the delivery process still runs on.
2015 – 2020
All Around Creative, Inc.
Subject matter expert on WordPress at scale, plus the Linux server management behind the sites running on it.
2011 – now
INAV8 Internet Solutions, Colombo
Founded the company, secured its funding, built the network infrastructure, and hired and trained the development team.
2010
IDM Computer Studies, Colombo
Taught Java and web development on the Charles Sturt University BIT curriculum. Teaching a thing is still the fastest way I know to find out whether I actually understand it.
2005 – 2008
Sprint Nextel, Denver
Wireless products and applications, plus a call-centre application I built in C#, ASP.NET, and SQL Server.
2002 – 2005
United States Army, Operation Iraqi Freedom
Ran an office accountable for ninety personnel, and deployed to Iraq for Operation Iraqi Freedom, computing firing solutions on the front line. Checklists, verification, and the cost of a wrong number when there is no undo.
1999 – 2002
Charles Darwin University, Australia
Built the university website on Lotus Domino as a Principal Certified Developer, and ran the residential college network for 250+ students. The first systems I was genuinely responsible for keeping alive.
TypeScript, JavaScript, Node.js, PHP, Python, Bash, SQL, C#
MySQL, MariaDB, PostgreSQL, Elasticsearch, Redis, ClickHouse
AWS, Google Cloud, Cloudflare, Hetzner, Docker, Kubernetes, Terraform, Coolify
Linux (RHEL, Debian, Ubuntu), systemd, Nginx, DNS and DNSSEC, SPF/DKIM/DMARC, BGP
React, Next.js, WordPress and Advanced Custom Fields at scale
LLM applications, RAG, agents, prompt engineering, evaluation harnesses
Ishan Karunaratne is a software systems architect and Chief Technology Officer. He has more than two decades of experience across software engineering, systems architecture, cloud infrastructure, and technology leadership, and is currently CTO at Rehab Media Group. He is a US Army veteran who served in Operation Iraqi Freedom, holds a Bachelor's degree from Charles Sturt University, and writes the developer publication TechEarl.
Software architecture and distributed systems, Linux and DevOps infrastructure, application security, and AI engineering. He built and operates DNS Checker, a domain intelligence platform that analyzes more than 240 million domains a day, and has published more than 790 technical articles at TechEarl.
Fair question, because there are several of us and search engines merge us enthusiastically. I am not the frontend engineer at Moresand Technologies, and I am not the founder and managing director of Sinhalite Holdings, the Sri Lankan hospitality and consumer-goods group written up in the Daily Mirror and Life Online. He appears to be doing very well. If you need compostable lunch sheets, that is the other one. If you need someone to work out why the database falls over at 3am, you are on the right page. The reliable way to tell us apart is my ORCID iD, 0009-0002-3088-0769, which is unique to me.
He is open to hands-on development work, which is still the part he enjoys most, as well as advisory work, technical due diligence, architecture review, and fractional CTO engagements. The fastest way to reach him is email.
Development work, which is still the part I enjoy most, plus advisory, technical due diligence, architecture review, and fractional CTO engagements. If you have a system that needs to hold up, I am interested.