K eltus
Custom-software studio

Hard problems,
shipped fast.

We design custom solutions for clients who need more than a template. Ultimate speed. Post-quantum encryption. AI integration. Go-powered automation. We listen to the problem, then build exactly what fits it.

  • 100Lighthouse score, every build
  • Post-quantumcryptography in production
  • Gofor the back-end-heavy lifting
Why this matters

Speed is king.

It helps dictate the rankings, along with SEO. With our systems, we get the max from both.

Receipts — rebuild

Sarah Westall site rebuild.

Same content, completely modernized — faster, more beautiful, more engaging, and with proper light and dark modes. WordPress on the left, our rebuild on the right.

WordPress (before)

sarahwestall.com

34
Perf
84
A11y
96
BP
92
SEO

Modernized rebuild (after)

dev.gnews.cz staging

99
Perf
100
A11y
100
BP
100
SEO

Try it on your own site →

Receipts — head to head

The New York Times vs. NewsTosser.

nytimes.com versus a live NewsTosser destination site. Same Lighthouse run, same day.

nytimes.com

Google PageSpeed, May 2026

32
Perf
88
A11y
54
BP
92
SEO

NewsTosser site

One of hundreds in the network

100
Perf
95
A11y
100
BP
100
SEO
How we work

Hard problems, shipped in days, not months.

Post-quantum cryptography. End-to-end-encrypted messaging. Voting platforms. Real-time AI. These are the problems most shops politely decline — and the ones we've spent careers solving.

What's new is the pace. With AI woven directly into our build pipeline, the boring 80% writes itself: scaffolding, tests, docs, glue. Our senior engineers spend their hours on the 20% that actually matters. Work that used to take a quarter ships in a week — same hardened stack, same engineers shipping it, at a fraction of the cost. Custom software that used to be enterprise-only is suddenly within reach.

  • faster delivery
  • Senior-builtAI-amplified, never AI-only
  • Surprisinglyaffordable
What we've built

Selected projects

All projects →
Latest case study

GNews.cz

GNews, an Eight Language Beast< Perfect Speed, Perfect SEO.

  • 8 languages
  • 40K pre-rendered pages
  • <250 ms TTFB
  • 100 Lighthouse
  • Zero trackers
  • Self-hosted analytics
Open the case study →
GNews.cz preview
Right now

Real people, reading this.

active visitors · last 60 min · refreshes every 30 s
Who's building

The team.

Meet everyone →
Meet the team

John Devlin

Lead Project Manager

Boca Raton, Florida, USA

Twenty years in software development, product and engineering management, with a habit of shipping under impossible deadlines. John runs every Keltus engagement end-to-end.

  • LinkedIn
Read full story →

Got a hard problem?

Speed. Crypto. AI. CNC automation. Tell us what you need — we'll tell you what's actually possible.

Start a conversation →