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For US, UK and EU enterprises stuck on .NET Framework, PHP 5/7, Java 8, Rails 4 or AngularJS monoliths. We do strangler-pattern modernization, not big-bang rewrites. Carve off one bounded context, run shadow traffic, prove parity, cut over with rollback in one config change. No 18-month projects that ship nothing until month 18.
Trusted by teams across Europe
Big-bang rewrites have a documented 70%+ failure rate. We do not do them. Strangler pattern means we carve off one bounded context at a time (auth, billing, reporting, customer-facing UI), build it on a modern stack, run it in shadow alongside the legacy system for 1 to 2 weeks, prove behavior parity, then route real traffic. If anything breaks, rollback is one config flag. You see business value every 8 to 12 weeks, not at month 36.
| Approach | Risk | Timeline | Business value cadence | Best for |
|---|---|---|---|---|
| Strangler pattern (us) | Low | 12 to 36 months | Every 8 to 12 weeks | Most legacy systems above 50k LOC |
| Big-bang rewrite | Very high | 12 to 24 months | End of project | Tiny systems (under 10k LOC) or planned shutdown |
| Replatform (lift and shift) | Low | 2 to 6 months | End of project | Cloud migration without code changes |
| Refactor in place | Medium | Ongoing | Each PR | Code in good shape, just dated patterns |
| Encapsulate (API in front) | Low | 3 to 9 months | Per consumer | Old system stays, new consumers via API gateway |
Honest take: we lead with strangler pattern because that is what works for the size of system most of our enterprise clients have (100k to 2M LOC). For smaller systems (under 10k LOC) or short-life systems, refactor in place or simple replatform may be enough. We assess and recommend, we do not push the most expensive option.
Pattern: 100k to 2M LOC monoliths on .NET Framework, PHP 5/7, Java 8, Rails 4 or AngularJS 1.x. Hiring is hard, scaling hits ceilings, security patches lag. Strangler pattern milestoned every 8 to 12 weeks.
Discuss your stack →Internal CRM and order management on .NET 4.7, SQL Server, jQuery UI. 800k LOC. Cannot hire engineers. Strangler-style migration to .NET 8 and React, 24 months, 1 carved context per quarter.
Custom PHP ecommerce (no Magento), 1.2M LOC. Cannot upgrade PHP without breaking 200+ client integrations. Encapsulate behind API gateway, then strangler new admin and customer apps.
2M LOC Java 8 application connecting SAP to 30 plants. Move to Java 21 + Quarkus on Kubernetes, modernize one integration at a time. 36-month engagement.
Practice management app on Rails 4. Cannot do big-bang due to HIPAA evidence requirements. Strangler to Rails 7 + Hotwire for new features, plus extracted React admin.
1.x AngularJS app, 200k LOC, 50+ engineers needed for next phase but no one wants to learn AngularJS. Strangler to React with module federation, route-by-route cutover.
2 to 4 week audit of code, schema, traffic and team. Identify bounded contexts (auth, billing, reporting, etc.) and prioritize by business risk and modernization value.
Adapter layer between old and new code. Translates legacy data shapes to clean domain models. So new code is not poisoned by old assumptions.
New service runs alongside old, gets copy of every request. Compare outputs, response codes, side effects, latency. Fix any divergence before cutover.
Cutover is one config flag flip per route or per percentage of traffic. Rollback is reverse flag flip in seconds. No code redeploy, no maintenance window.
During migration window both old and new systems write. Change-data-capture (Debezium) keeps both in sync. Final cutover is read-then-stop on old, validate, allow writes on new.
API gateway or reverse proxy (Kong, Envoy, NGINX) routes per-route to old or new. Rollout is one route at a time, not all-or-nothing.
Old code stays running until 0% traffic, plus 30-day silent monitoring. Then deprecation cycle. Then deletion. We do not leave zombie code.
Architecture docs, decision records, runbooks. Pairing sessions with your engineers. By engagement end your team can extend the new system without us.
Dedicated team, monthly billing. Includes audit, modernization plan, rolling delivery, knowledge transfer to your team. For deep-dive on TCO, see cost of nearshore software development 2026.
Carve off 1 bounded context (e.g., billing), modernize, cut over. 1 senior architect, 2 senior backend, 1 DevOps. Right for testing the strangler approach before scaling. 6 to 9 months.
3 to 5 bounded contexts modernized in parallel waves. 1 staff engineer, 3 senior backend, 1 senior frontend, 1 DevOps. Right for 200k to 800k LOC systems. 12 to 24 months.
Full system, multi-year. 1 staff, 4 senior backend, 2 senior frontend, 1 senior DevOps, 1 QA, 1 PM. Right for 1M+ LOC enterprise systems. 24 to 36 months, milestoned per bounded context.
Current stack, system size (LOC, tables, traffic), business pain points, hiring constraints, regulatory load. We propose audit scope and budget within 5 working days.
Senior architect plus 1 senior backend audit code, schema, infrastructure, deployment. Identify bounded contexts, prioritize by business risk and modernization value. Audit report includes carved-off candidate list with cost-benefit per context.
Modernization roadmap with carved-off contexts, milestones, cutover criteria. Team composition (titles, seniorities, ramp plan). Stakeholder review and sign-off.
Team assembled, anti-corruption layer scaffolded, shadow infra (gateway, observability, parity test harness) deployed. First bounded context backlog refined.
First bounded context built, shadow tested for 1 to 2 weeks, cutover by feature flag in stages (1%, 10%, 50%, 100%). Old code path retained until 30-day silent monitoring done. Repeat for next context.
Anti-corruption layer between old and new code, shadow traffic for 1 to 2 weeks, parity proven before flag flip. Each carved-off service stays behind a feature flag for 30 days of silent monitoring before deprecation.
No big-bang. No 18-month projects that ship nothing until month 18. Business value every 8 to 12 weeks, milestoned per bounded context.
See full case studyModernize when the cost of NOT modernizing exceeds the cost of doing it: hiring becomes hard (no one wants to learn legacy stack), security patches lag, scaling hits a ceiling, integrations need workarounds. Leave it alone when the system works, change is rare, and total cost of ownership is low. The honest answer is rarely "rewrite everything".
Strangler pattern in 95% of cases. We carve off one bounded context at a time (auth, billing, reporting), reroute traffic to the new service, retire the old code, repeat. Big-bang rewrites have a 70%+ failure rate per industry data. The 5% where big-bang wins: tiny systems (under 10k lines), or business shutting down old product anyway.
Audit: 2 to 4 weeks. Strangler-style modernization: 12 to 36 months depending on system size, traffic volume, regulatory load. We milestone every 8 to 12 weeks against carved-off bounded contexts (auth, billing, customer-facing UI, internal admin). You see business value at every milestone, not just at month 36.
Source: PHP 5/7, .NET Framework, Java 8, Ruby on Rails 4/5, AngularJS 1.x, jQuery monoliths, classic ASP, ColdFusion. Target: TypeScript/Node, Go, Java 21+, .NET 8+, Python/FastAPI on modern infra (Kubernetes, AWS, Azure). We have engineers comfortable in legacy stacks who can do parallel-run testing during cutover.
With strangler pattern, no perceptible downtime. Each carved-off service goes live behind feature flag with shadow traffic for 1 to 2 weeks before cutover. We measure parity (response codes, latency, side effects) before flipping the flag. Rollback is one config change. We have done this for systems handling 50M+ daily requests.
Two-way sync during migration window (CDC via Debezium or vendor tools). Old and new systems both serve traffic until parity is proven. Final cutover is read-then-stop on old, validate, allow writes on new. We have migrated multi-TB databases with sub-1-minute switchover windows.
Tell me the stack, system size and business pain. We propose audit scope and budget within 5 working days. Audit deliverable is yours regardless of whether you continue with us.
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