Legacy Application Modernization Services

100+ legacy systems revamped: we’ve slashed dev time, automated entire operations in just months, and helped apps with 50K+ users win investor trust.
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    Top IT Services Company, 2025
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    Top Software Development Company, 2025
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    Top Ukrainian Cloud Server Migration Company, 2025
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    Top B2B Company Globally, Fall 2024

Iman Fadaei
Iman Fadaeiuk

Founder & CEO

They have a broad knowledge base and are ahead of their competitors technically.

Serves Genpact

$400M portfolio company

Murtaza Dabawala
Murtaza Dabawalausa

CEO

We’ve developed great products and achieved tremendous success.

Google Cloud Partner

Trusted by Fortune 5 UHG

Ignacio Doncel
Ignacio Doncelusa

Founder at WishYoo

Clockwise understood exactly what we wanted to deliver to our users.

90

countries worldwide user base

5+

years together

Banning Stack
Banning Stackusa

Principal Estimator at SIDE Partnership, LLC

The team produced excellent materials throughout the discovery phase.

12+

years in all facets of cost estimating

$250k+

value of projects in progress

01 | 04

Fortune #40 Global Health Leader

1886-founded | 131K employees | $16B in R&D

NYSE: EB

850k creators | 300M tickets sold in 2023

8th GPS App in the US

3M+ in 2023 | 10M+ Google Play downloads

Cultural Exchange Led by 2K+ Team

Est. 1980 | 500K+ Alumni | 100+ Countries

$12M Revenue Tech Co.

MBE Certified by NMSDC

Trusted Logistics Co. Since 1979

ISO9001 Certified Systems Integrator

3rd in Retail Inc. 5000

$6M+ raised | #1 ranked company in CT

UCSF-Trusted Health App

with 50K+ users in 60+ countries

Google-Funded Green Tech

144K Ha Monitored | Featured by Reuters

Telecom Experts Est. 2005

Google, Proximus & Orange partners

NASA-Trusted Workflows Builder

Est. in 2007 | PCI, GDPR & HIPAA certified

Top Swiss Agency

Awarded #1 Swiss App in 2025

#2 SMM Agency in Australia

Serves 1k+ Australian B2B across 20+ domains

Google Cloud Partner

Trusted by Fortune 5 UHG

F&B Startup with 25K+ Guests/Y

4.5 on TripAdvisor | 600+ Dining Partners

Fortune #40 Global Health Leader

1886-founded | 131K employees | $16B in R&D

NYSE: EB

850k creators | 300M tickets sold in 2023

8th GPS App in the US

3M+ in 2023 | 10M+ Google Play downloads

Cultural Exchange Led by 2K+ Team

Est. 1980 | 500K+ Alumni | 100+ Countries

$12M Revenue Tech Co.

MBE Certified by NMSDC

Trusted Logistics Co. Since 1979

ISO9001 Certified Systems Integrator

F&B Startup with 25K+ Guests/Y

4.5 on TripAdvisor | 600+ Dining Partners

Google Cloud Partner

Trusted by Fortune 5 UHG

#2 SMM Agency in Australia

Serves 1k+ Australian B2B across 20+ domains

Top Swiss Agency

Awarded #1 Swiss App in 2025

NASA-Trusted Workflows Builder

Est. in 2007 | PCI, GDPR & HIPAA certified

Telecom Experts Est. 2005

Google, Proximus & Orange partners

Google-Funded Green Tech

144K Ha Monitored | Featured by Reuters

UCSF-Trusted Health App

with 50K+ users in 60+ countries

3rd in Retail Inc. 5000

$6M+ raised | #1 ranked company in CT

Trusted Logistics Co. Since 1979

ISO9001 Certified Systems Integrator

$12M Revenue Tech Co.

MBE Certified by NMSDC

Cultural Exchange Led by 2K+ Team

Est. 1980 | 500K+ Alumni | 100+ Countries

8th GPS App in the US

3M+ in 2023 | 10M+ Google Play downloads

NYSE: EB

850k creators | 300M tickets sold in 2023

Fortune #40 Global Health Leader

1886-founded | 131K employees | $16B in R&D

F&B Startup with 25K+ Guests/Y

4.5 on TripAdvisor | 600+ Dining Partners

Google Cloud Partner

Trusted by Fortune 5 UHG

#2 SMM Agency in Australia

Serves 1k+ Australian B2B across 20+ domains

Top Swiss Agency

Awarded #1 Swiss App in 2025

NASA-Trusted Workflows Builder

Est. in 2007 | PCI, GDPR & HIPAA certified

Telecom Experts Est. 2005

Google, Proximus & Orange partners

Legacy app modernization services we deliver

Strategic tech audit

We review architecture, code, and workflows to shape a roadmap that supports your business direction.

Seamless system integration

We design reliable APIs that sync your app with internal tools and third-party platforms without friction.

Bring AI into your product

From chat assistants to smart recommendations, we add AI that solves real problems and saves time.

Tailored feature development

Add the functionality your users need, while keeping the core of your system intact.

Modernization services we provided

usaHealthcareSaaSDedicated Development TeamData Visualization
Headsup

Health tracking platform

Revamped UI/UX for web and mobile, improving the experience for 50K+ global users. Set up and maintained end-to-end QA process incl. hiring and management.

4+

years of ongoing collaboration

Series A

funding raised in 2024

Headsup
ukMarketplaceSaaSMobile Development
Whitelance

White-label marketplace app

Transformed the client’s platform into a scalable white-label solution that now serves businesses in 150+ countries, including companies valued at over $3B.

150+

features became available for businesses

5.0

on Clutch

4

continents using the platform

Whitelance
usaMarTechSaaSData Visualization
Sparrow Charts

Social media marketing analytics tool

Implemented a dynamic UI based on D3.js capabilities that became the UVP for our client’s product, which was acquired in 2024.

1.5K

users gained after beta-testing

2022

Grant from Scale-Up Minnesota

Sparrow Charts
usaEntertainment
Eventbrite

Extension for an event management platform

Created a scheduling extension for Eventbrite, allowing 10M+ users to automatically publish and edit events at optimal times.

5.0

on Upwork

4.1

on Google Chrome

Eventbrite
ukMarTechSaaSAI
Releasd

LLM-powered PR reporting tool

Added LLM functionality to a coverage reporting tool, opening an $11.6B market for a client’s product that is trusted by global brands like BBC and Renault.

Case in progress

1

month PoC delivered

4.7

on Capterra

Releasd
ukHealthcareMobile Development
Fika

Mental fitness app

Rewrote and enhanced an iOS/Android app for a mental health startup, introducing new features and supporting its top 5 UK Health & Fitness App ranking.

Case in progress

£1.2M

seed funding raised

40K+

app registrations

Fika
01 | 0601 | 06

Testimonials

Iman Fadaei
Iman Fadaeiuk

Founder & CEO

Clockwise helped us turn our marketplace into a product available as a service. They enabled multitenancy, allowing users to create service marketplaces for any business worldwide. The team is clear, organized, and always available, accommodating our needs. Their broad knowledge and technical expertise put them ahead of competitors.

Dan Weber
Dan Weberuk

President

I needed a larger development team to expand my company, and Clockwise Software has been instrumental in developing four mobile applications. They’ve provided QA testing, automated testing, and implementations using React, Redux, and Node.js. Two apps achieved 100% code and branch coverage, and another reached 99.4%. I’m very pleased with the quality of the work we’ve done together.

Ignacio Doncel
Ignacio Doncelusa

Founder at WishYoo

We needed to enhance our UX by redesigning our platform to make it more engaging. Clockwise Software restructured the backend to ensure intuitive functionality and delivered an eye-popping design. They were professional, always available, and effective communicators, quickly learning our tools. The system passed stress tests with 5,000 users and showed no lag, exceeding our expectations.

Nicolas Slatiner
Nicolas Slatinerusa

Lead Front-end Developer at Orthodox Union

The Clockwise Software developers always help us achieve our goals. Communication is always excellent and deadlines are met most of the time. They’re very transparent. So, It was easy for us to plan ahead whenever there was a complicated task.

They have a very impressive tech understanding. They are very good with all the technologies they work with.

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Legacy modernization services steps

Here’s how the process of legacy modernization services looks like:

Discovery & digital audit

We take a step back before touching the code. First, we dig into how your system works: codebase, architecture, integrations, and performance. Then we identify what’s holding you back, whether it’s slow delivery, scaling issues, or rising maintenance costs. From there, we shape a legacy application modernization plan that minimizes risk and downtime while preserving the logic and features your business depends on. You’ll know what’s changing, why it matters, and how we’ll keep your system stable during the transition.

Learn more

Solution design & planning

We work with you to shape how the modernized system will function, from architecture and tech stack to user flows and UI. Our business analyst maps your current workflows and needs based on real user behavior and input from your team. Meanwhile, a solution architect audits the technical setup: architecture, databases, APIs, scaling limits, and existing tech debt. A project manager defines how we’ll communicate, collaborate, and transfer knowledge as the project moves forward.

You’ll get wireframes, architecture diagrams, and a rollout plan that solves day-to-day issues like manual work, poor UX, or disconnected tools.

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Building your digital solution

With the plan in place, we move into legacy modernization solutions development, modernizing your system step by step, without unnecessary disruption. Whether it’s refactoring, replatforming, or rebuilding, our team works in short, focused sprints with full transparency. We make it easy to track delivery, see what’s ahead, and understand how the project is performing.

We stay flexible as priorities shift and use metrics like CPI and SPI to spot issues early and keep progress steady. Forget surprises, you’ll see results through clear updates, demos, and meaningful iteration.

Built-in quality assurance

QA is woven into every step of the legacy application modernization process, not left until the end. We don’t just test for bugs; we test for real-world value. That means checking critical workflows, catching edge cases early, and making sure the system reduces manual effort and avoids costly errors.

Our team combines automated and manual testing to cover performance, user roles, and integrations. Features are validated in realistic scenarios with your team involved during the final stages, so what gets shipped actually works for the way you operate.

With step-by-step rollouts, your team has time to test, adapt, and provide feedback, ensuring the product evolves smoothly, with no disruptions.

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Deployment & launch

We plan deployment with stability and business continuity in mind. From staging tests to phased rollouts, every step is designed to prevent surprises and ensure a smooth transition. Your business logic stays intact, your data moves safely, and your team stays in the loop.

Whether it's a full switch or a gradual release, we align timing to avoid downtime. We set up CI/CD pipelines or deployment scripts when needed, and where it makes sense, we run early launches to fine-tune performance and gather feedback. We keep a close watch post-launch to ensure the system performs and your team gets the results they need.

Modernize with full control

Deadlines that hold

Costs you can trust

No blind spots

Proactive risk planning

Modernization without the wait

When your business runs on the system we’re modernizing, timing matters. Our legacy modernization company tracks progress with SPI, runs regular checkpoints, and flags risks early, so you’re always aligned. With sprint boards, demos, and check-ins, you see exactly where things stand and what’s coming next.

transparent legacy app modernization

Best partner for your transformation

  • Top Eastern European engineers, PMI-based processes, and QA that digs deep
  • CPI/SPI tracked in real time: scope aligned, timelines in check
  • 1 hire out of 200: test-driven, interview-proven, handpicked talent
  • Structured updates and a comms plan that keeps everyone on the same page
  • Clear reports, code access, full visibility
  • Fast setup, flexible terms, zero bureaucracy

100+

apps modernized

99.89%

acceptance rate

3.3

years avg. tenure

5.5%

employee churn rate

<10%

CPI & SPI variance

94.12%

satisfaction rate

Free consultation

Wondering if your legacy system is still salvageable? We’ll help you figure it out. Contact us.

  • Response in 24 hours
  • Estimate in 10 days
  • Experts involved
Serhii

Head of Client Relations

Eugene

Account Executive

Serhii photoEugene photo

Solutions we modernize to perform best

SaaS and customer-facing platforms

Modernize your architecture to scale with users, ship without fear, and iterate freely.

Marketplaces and booking systems

Untangle logic, streamline flows, and keep scheduling and transactions rock-solid at scale.

Location-based and logistics apps

Refactor your backend to manage dynamic data, connected fleets, and optimized delivery paths.

Straight to the common questions

Is a full rebuild necessary?

Only if there’s no smarter path. We start legacy application modernization services with a deep technical and business audit to understand what’s worth keeping and what’s getting in your way. In most cases, we preserve what still delivers value and modernize only the parts that truly need it. It’s not a total redo. It’s smart legacy application modernization, focused on real bottlenecks.

Can the system keep running while you update it?

We modernize without getting in your way. By using parallel environments, staggered rollouts, and close coordination, we make sure your team stays productive while we handle the technical changes in the background. Business runs as usual while we modernize in the background.

How do you prevent data loss or format issues during migration?

We treat data migration as a high-stakes move, and plan it accordingly. Migration typically happens in stages to reduce risk and avoid downtime. If a brief maintenance window is needed, we schedule it during off-hours and keep communication clear.

We run dry runs and validation beforehand to catch issues early, because once data flows to the new system, there’s no undo button. If you're keeping old integrations, we ensure compatibility. If you're phasing them out, we help you transition smoothly without breaking your workflow.

What’s the expected cost of software modernization?

It depends on what we’re modernizing. Reworking a small internal tool isn’t the same as upgrading a multi-layered platform. We’ve delivered modernization projects ranging from $20K to over $1M, so there’s no one-size-fits-all legacy software modernization services price.

What you will get is a clear, reliable estimate. During discovery, we break down what needs attention, what can stay, and where you’ll get the most impact. You’ll see detailed scope, timelines, and cost projections, with CPI tracked to keep variance under 10%, so you can plan with confidence.

What’s the typical timeline for a software transformation?

It depends on the scope. A focused update might take 3–4 months, while a full-scale transformation across multiple systems could run a year or more.

You won’t be guessing. After discovery, we’ll give you a clear software modernization services roadmap with phased delivery, priorities, and realistic timelines. We track SPI to stay on schedule and surface any blockers early.

You’ll see progress early, too. We release improvements in stages, so you don’t wait months to get results. Most clients start seeing impact within the first few sprints

Will the delivered solution match the level of quality we need?

Quality guides how we design, build, and release, not just how we wrap up. From clear requirements and peer reviews to automated testing and real QA coverage, we know how to modernize legacy applications, keeping standards high at every stage.

You get regular demos, visibility into progress, and a feedback loop that actually works. Many clients tell us we deliver with more care and precision than their internal teams, not just in output, but in how we take ownership. Whatever your benchmarks are, we meet them and often raise the bar.

Will we have access to progress updates and planning?

You’ll have full access to what’s happening, from sprint boards and documentation to delivery timelines and release plans. We keep communication steady through regular check-ins, async updates, and live demos, so you’re never left guessing.

You’re part of the process, not just watching from the sidelines. You’ll review progress, shape priorities, and weigh in on key decisions as the project evolves. Full access and constant collaboration, that’s the standard.

Can our team take over the system after delivery?

We don’t build systems that tie you to us. You’ll get full access to code, infrastructure, and documentation, along with a clear transition plan. Knowledge transfer starts early, not at the end, so your team stays in the loop throughout the legacy application modernization process.

By the time we wrap up, your team will know the system inside and out, ready to run, scale, and improve it without hesitation.

What ensures you’ll deliver what we actually agreed to?

We make alignment a priority from the start. Whether you bring detailed specs or a rough idea, we work with you to define features, user flows, and priorities clearly, using wireframes, documentation, and business analysis to build a shared understanding.

You’ll see working demos early and often, so you can give feedback and fine-tune before anything goes live. Agile keeps us flexible, but never off-track.

After launch, we stay close to real user feedback and help you turn it into improvements, so the system stays aligned with both your vision and your users’ needs.

Will our core team remain the same throughout the process?

Consistency is a core part of how we work. The developers, QA engineers, and project lead assigned to your project stay with it from the start. They’ll get to know your system deeply, both technically and in terms of business goals, which protects quality and momentum.

Our average team member stays with us for 3.8 years, and our churn rate is just 5.5%, well below industry averages. If a change ever comes up, we handle it with proper onboarding, clear documentation, and direct support from the existing team, so there’s no drop in delivery or direction.

How do you make sure our team can maintain the code later on?

We make sure your team gains context as we go, so there’s no scramble at the end. Your developers can join syncs, follow technical decisions, and review the code as it evolves, so they’re never playing catch-up.

All documentation is clear, structured, and accessible, from setup steps and architecture decisions to how each part of the system works. If you decide to bring development in-house or move to another vendor, we support the transition with walkthroughs, final docs, and direct handover. You’re ready. Nothing’s lost.

Will we run into misunderstandings due to language?

Clear communication is core to our modernization of legacy applications. Our team operates in English daily with international clients, so you won’t deal with miscommunication, vague responses, or unnecessary back-and-forth.

We keep things clear, concise, and async-friendly when needed. And if something’s unclear, we’ll speak up, not let it slide. That’s a big reason clients trust us to move fast without friction.

Do we get full ownership of everything you build?

All code, documentation, and infrastructure we create during the project is yours to use, modify, and scale however you like. Ownership terms are clearly spelled out in our agreement upfront, so there’s no confusion later. We don’t hold anything back or lock you in.

How do you keep projects on track despite the situation in Ukraine?

We’ve built our operations for resilience. With a distributed team, energy-independent setup, and infrastructure that’s not tied to any single location, legacy application modernization work continues without delays or slowdowns, no matter the external conditions.

Since 2022, we’ve continued shipping on time, growing our team, and maintaining strong, long-term client relationships. When you work with us, you’re choosing a partner that plans for challenges and keeps projects moving through them.

Can we trust your estimates to hold up through delivery?

Yes. Our numbers come from real projects, not assumptions. After discovery, you’ll get a clear breakdown of features, timelines, and costs. During the legacy modernization project, we track CPI to keep budget variance under 10% and flag any shifts early, so nothing slips through unnoticed.

You stay informed, involved, and in control, every step of the way.

Key people

Andrii
Andrii
Founder & CEO
Clockwiser from Day 1 | Led Clockwise to Top Ukrainian IT Company
Andrii
🎤 Karaoke champion
🧠 Quiz monster
🐈 Cat team
Bogdan
Bogdan
Head of Delivery
10 y. of experience | Set up delivery with 99.88% acceptance rate
Bogdan
🏂 Snowboarder
💿 DJ
🥁 Drummer
☕ Coffeeholic
Serhii
Serhii
Head of Client Relations
11 y. of experience | 98% client satisfaction rate
Serhii
🚞 Traveller
Gym rat
☕ Coffeeholic
Natalia
Natalia
Head of People
10 y. of experience | 100+ hired talents
Natalia
Hyggeist
Wanderlust Soul
🏊‍♀️ Swimmer
🕯️ Detail Aesthete
Mike
Mike
Solution Architect
15 y. of experience | 50+ projects with 99,99% uptime reliability
Mike
🧑‍🍼Father of 3
Pavlo
Pavlo
Tech Lead
15 y. of experience | Managed 40+ developers as Tech Lead
Pavlo
💨 Motorhead
🧰 Tinkerer
Andrii
Andrii
Founder & CEO
Clockwiser from Day 1 | Led Clockwise to Top Ukrainian IT Company
Andrii
🎤 Karaoke champion
🧠 Quiz monster
🐈 Cat team
Bogdan
Bogdan
Head of Delivery
10 y. of experience | Set up delivery with 99.88% acceptance rate
Bogdan
🏂 Snowboarder
💿 DJ
🥁 Drummer
☕ Coffeeholic
Serhii
Serhii
Head of Client Relations
11 y. of experience | 98% client satisfaction rate
Serhii
🚞 Traveller
Gym rat
☕ Coffeeholic
Natalia
Natalia
Head of People
10 y. of experience | 100+ hired talents
Natalia
Hyggeist
Wanderlust Soul
🏊‍♀️ Swimmer
🕯️ Detail Aesthete
Mike
Mike
Solution Architect
15 y. of experience | 50+ projects with 99,99% uptime reliability
Mike
🧑‍🍼Father of 3
Pavlo
Pavlo
Tech Lead
15 y. of experience | Managed 40+ developers as Tech Lead
Pavlo
💨 Motorhead
🧰 Tinkerer
Dmytro
Dmytro
Tech Lead
15 y. of experience | 10+ AWS projects led
Dmytro
🏎️ F1 Fan
🍻 Beer connoisseur
☕ Coffee aficionado
Yana
Yana
Design Lead
12 y. of experience | 100% UI/UX acceptance rate after user tests
Yana
👩‍🎨 Local artist
🧘‍♀️ Yoga practitioner
🦻Hearing Accessibility Advocate
📚 Bibliophile
Bogdan
Bogdan
QA Lead
17 y. of experience | QA Lead on 10+ multi-domain projects
Bogdan
🎓 Nerd
⛷️ Ski fan
Strong Spirits expert
Andrii
Andrii
Project Manager
8 y. of experience | 30+ projects delivered
Andrii
🏎️ Junior Car Drifter
🧳 Traveller
☕ Coffee enthusiast
Tetiana
Tetiana
Business Analyst
5 y. of experience | Saves $30K on avg./client with discovery
Tetiana
🧠 Braving the unknown
💬 Empathy-driven communicator
🏖️ Passionate traveler
Yelyzaveta
Yelyzaveta
Tech Lead
9 y. of experience | 10+ React projects led, 1.5+ years each
Yelyzaveta
⛸️ Figure skater
🏔️ Explorer at heart
🪴 Bonsai & bloom keeper
📖️ Avid reader
01 | 04

Awards

Show more
Top Software Development Company, 2025
Top Software Development Company, 2025
Top IT Services Company, 2025
Top IT Services Company, 2025
Listed Among Top 1000 Companies Globally
Listed Among Top 1000 Companies Globally
Top NodeJS Developers, 2025
Top NodeJS Developers, 2025
Top Managed Service Provider in 2025
Top Managed Service Provider in 2025
Top Software Development Company, 2025
Top Software Development Company, 2025
Top IT Services Company, 2025
Top IT Services Company, 2025
Listed Among Top 1000 Companies Globally
Listed Among Top 1000 Companies Globally
Top NodeJS Developers, 2025
Top NodeJS Developers, 2025
Top Managed Service Provider in 2025
Top Managed Service Provider in 2025
Top Ukrainian Cloud Server Migration Company, 2025
Top Ukrainian Cloud Server Migration Company, 2025
Top Ukrainian Hosting and Cloud Service Company, 2025
Top Ukrainian Hosting and Cloud Service Company, 2025
Top Ukrainian IT Services Company for Real Estate
Top Ukrainian IT Services Company for Real Estate
Top Software Developers for Advertising and Marketing, 2025
Top Software Developers for Advertising and Marketing, 2025
Top IT Services Company for GPS Navigation and GIS, 2025
Top IT Services Company for GPS Navigation and GIS, 2025
Top Software Development Company in Ukraine for Startups
Top Software Development Company in Ukraine for Startups
Top Software Development Company for Small Businesses
Top Software Development Company for Small Businesses
Top React Development Company
Top React Development Company
Top B2B Company Globally, Fall 2024
Top B2B Company Globally, Fall 2024
Top B2B Company Globally, Spring 2024
Top B2B Company Globally, Spring 2024
Top Software Development Company, 2023
Top Software Development Company, 2023
Top IT Services Company, 2023
Top IT Services Company, 2023
Most Reviewed Software Developers on Clutch
Most Reviewed Software Developers on Clutch
Top NodeJS Development Company, 2023
Top NodeJS Development Company, 2023
Top Software Development Company for Marketing and Advertising, 2023
Top Software Development Company for Marketing and Advertising, 2023
Top Ukrainian IT Services Company for Advertising and Marketing
Top Ukrainian IT Services Company for Advertising and Marketing
Top Ukrainian Development Company, 2021
Top Ukrainian Development Company, 2021
Top Ukrainian Development Company, 2020
Top Ukrainian Development Company, 2020
Top Ukrainian B2B Company, 2019
Top Ukrainian B2B Company, 2019
Top Ukrainian Development Company, 2018
Top Ukrainian Development Company, 2018
01 | 25

10+ years of modernizing legacy apps

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