Increase velocity.Reduce complexity.Enable AI.

We rebuild your system so it can support scale, speed, and modern capabilities.

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Your system is holding
everything back

What once enabled growth now limits it. As systems scale, complexity compounds, slowing development, increasing costs, and turning simple changes into risks. At the same time, AI requires clean data, flexible architecture, and fast iteration. Most systems weren't built for that. So while the market moves forward, your system holds you in place.

Velocity

5–10× faster shipping

Ship features in days instead of weeks with modern architectures

Iteration

10× faster iteration

Move faster with systems designed for scale, modularity, and AI

AI Impact

AI that actually ships

Turn AI into real product capabilities instead of stalled initiatives

We don't patch systems. We rebuild them from the core, creating architectures that scale, reduce complexity, and make real AI capabilities possible.

WHAT WE DO

Everything you need to modernize

Legacy Rebuilds

Rebuild the core, without disrupting the business

We modernize the architecture in phases, improving performance without disrupting operations.

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Modernization Audit

A clear picture of what's holding you back

We analyze architecture, data flows, and dependencies to uncover where complexity and risk are coming from.

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Product Interface Rebuilds

Modernize how the system delivers value

We rebuild front-end architectures to be fast, maintainable, and ready for the future.

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AI Readiness

Get your system ready for real AI

We restructure data, simplify architecture, and enable the workflows needed to integrate AI into production.

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OUR APPROACH

How we work

Understand
01

Understand your system and what's holding you back

We get clear on your architecture, challenges, and where constraints are coming from.

Define
02

Design the target system

We map what your system needs to become to support scale, speed, and AI.

Plan
03

Create a clear path forward

We break the work into phases with priorities, timelines, and expected impact.

Rebuild
04

Modernize the system in the right order

We rebuild in phases, from core infrastructure to user-facing interfaces, improving performance without disrupting operations.

Enable
05

Unlock speed, scale, and AI

Your system is ready to move faster, scale cleanly, and support what's next.

We don't patch systems. We rebuild them from the core.

Patching legacy systems creates more complexity over time. Real modernization means rebuilding from the core — in phases — so you get a system that's faster, simpler, and ready for whatever comes next.

Eli5 team working
Eli5 team working
TESTIMONIALS

Results speak for themselves

80+

We've modernized over 80 systems and products, helping teams move faster and making them ready for the next era of technology.

Floris
Wesley
Team member

Talk directly to one of our leaders about your challenge

Schedule a free brainstorm

“Our platform was becoming harder to scale and slower to evolve. Eli5 reworked the core architecture and gave us a system that's faster, more stable, and ready for what's next.”

Eric Kickert

Eric Kickert

CEO, Peecho

CEO, Peecho

Founder, A-Insights

“Our system was holding back internal operations and product development. Eli5 modernized the foundation, simplifying complexity and enabling us to move faster with far less friction.”

Bart Zirschky

Bart Zirschky

Founder, A-Insights

“We started with a system that wouldn't support where we wanted to go. Eli5 rebuilt it at the core, giving us a scalable foundation that makes building and evolving the product significantly easier.”

Niek Delis

Niek Delis

CEO, Typejust

CEO, Typejust

WHY ELI5

We don't build features. We unlock velocity.

  • 01

    We fix what's actually holding you back

    We go to the core and remove the constraint so the system can move again.

  • 02

    We build systems that move with you

    Aligned with how your product evolves, without slowing you down as you grow.

  • 03

    We design for what comes next

    Scale, speed, and AI are built into the foundation from the start.

  • 04

    We modernize without breaking what works

    No big bang. Just controlled progress while your business keeps running.

  • 05

    We understand complex systems deeply

    We understand complex enterprise systems and build with the latest in modern architecture and AI.

RESOURCES

From the team

The CAPEX and OPEX of software modernization
3 min read

The CAPEX and OPEX of software modernization

Floris van der Veen
Floris van der Veen
Eli5 article review series: The end of one-time software modernization projects
9 min read

Eli5 article review series: The end of one-time software modernization projects

Wes Botman
Wes Botman
Why most AI pilots fail — and what modernized systems do differently
5 min read

Why most AI pilots fail — and what modernized systems do differently

Floris van der Veen
Floris van der Veen
The CAPEX and OPEX of software modernization
3 min read

The CAPEX and OPEX of software modernization

Floris van der Veen
Floris van der Veen
Eli5 article review series: The end of one-time software modernization projects
9 min read

Eli5 article review series: The end of one-time software modernization projects

Wes Botman
Wes Botman
Why most AI pilots fail — and what modernized systems do differently
5 min read

Why most AI pilots fail — and what modernized systems do differently

Floris van der Veen
Floris van der Veen
The CAPEX and OPEX of software modernization
3 min read

The CAPEX and OPEX of software modernization

Floris van der Veen
Floris van der Veen
Eli5 article review series: The end of one-time software modernization projects
9 min read

Eli5 article review series: The end of one-time software modernization projects

Wes Botman
Wes Botman
Why most AI pilots fail — and what modernized systems do differently
5 min read

Why most AI pilots fail — and what modernized systems do differently

Floris van der Veen
Floris van der Veen

Let's talk about your system

Tell us what you're working with and we'll help you figure out where to start.

hello@restacked.io

Common questions, clearly answered.

Still have questions about modernizing your system? Talk to one of our leaders directly.

Contact us

  • Look for a team that works at the system level, not just the code level. Modernization is about making the right architectural decisions, not just rewriting parts. If they can't clearly explain trade-offs, risks, and long-term impact, they're not the right partner.

  • No. Most systems can be modernized in parts. The key is knowing what to rebuild and what to keep. Rebuilding everything is rarely the right move. Patching everything almost always makes things worse.

  • It shouldn't. Modernization should happen in controlled phases, with critical systems kept running. If the approach requires a full stop or "big bang" migration, the risk is usually too high.

  • Yes, but only to a point. AI can accelerate parts of the process like analysis, refactoring, and testing. But the real challenge is architectural decisions. That still requires experience.

  • A structured breakdown of your system, including architecture, data flows, bottlenecks, and risks. You get a clear view of what's holding you back and a practical plan to move forward.

  • In most cases, the backend comes first. That's where scalability, performance, and data structure are defined. Improving the frontend without fixing the core usually leads to more complexity.

  • The system becomes easier to work with, easier to scale, and ready for what's next. Teams move faster, complexity drops, and capabilities like AI can actually be implemented.

Eli5 — Software Modernization Consultancy