Legacy Software Modernization Services for US & EU Companies

Pricing is fixed-scope and all-in, quoted in USD across three tiers. An audit plus quick wins runs from $2,300; systemic refactoring of the first bounded contexts from $9,200; a full end-to-end modernization from $28,700. The exact number is driven by system size and coupling, data-migration risk, compliance scope and the target platform. You see the line-item budget at the end of discovery and sign off before any code is written. There is no recruitment markup, no tool surcharges, and cloud fees run on your own accounts so you keep the cost lever.

In most cases, modernise. Full rewrites fail at a rate well above 50% because they freeze the roadmap, multiply scope, and force a single high-risk cutover. We default to the strangler-fig pattern: keep the legacy system running, route new traffic to extracted microservices one bounded context at a time, and retire legacy code only after the new path is proven in production. A rewrite is justified only when the legacy stack is unmaintainable, no engineers remain, or compliance forces it — and even then we phase it.

Strangler-fig is an incremental refactoring pattern: a routing layer sits in front of the legacy system and gradually redirects requests for specific capabilities to new microservices. The legacy code keeps running for everything not yet migrated. Each bounded context — orders, billing, identity — is extracted, deployed, dual-run for validation, then cut over. Rollback is a routing change, not a redeploy. Over months the new system “strangles” the old one until the legacy app can be safely deprecated.

Discovery and migration plan run 4–6 weeks. The migration itself depends on system size and risk appetite: a mid-size .NET Framework or PHP monolith with 200–400 KLOC typically lands in 9–18 months of incremental cutover. Mainframe and COBOL programmes run multi-year by design. We work in 2–3 month phases with a demoable cutover at the end of each phase, so business value lands continuously instead of waiting for a big-bang release.

Yes, that is the point of strangler-fig. The legacy system stays in production throughout. Traffic shifts behind a routing layer (API gateway, reverse proxy, or feature flag) as each bounded context comes online. We dual-run the old and new paths, compare outputs, and only flip the canonical write once parity is confirmed. Maintenance windows are limited to database cutovers and are usually under one hour, scheduled with your operations team.

Yes. We have shipped modernisations across .NET Framework 4.x to .NET 8, Java 8 to Java 21 on Spring Boot, PHP 5/7 to PHP 8 and Node.js, Delphi/Pascal to C# and TypeScript, Oracle Forms and PL/SQL to PostgreSQL with Node or Java services, classic ASP and VB6 to modern web stacks, and AngularJS/Knockout/jQuery to React, Vue, or Next.js. COBOL and mainframe workloads are handled in partnership with specialist re-hosting vendors when needed.

Data is the highest-risk part of any modernisation, so we treat it as a first-class workstream. We start with change data capture (Debezium, native log shipping, or vendor CDC) to keep new and old stores in sync. During dual-run, writes go to both systems and a reconciliation job flags divergence inside one hour. We freeze the legacy write path only after a parity window — typically 2–4 weeks — and keep the legacy database as a read-only fallback for 90 days after cutover.

Yes, and that is the default. Strangler-fig lets the feature team and the modernisation track run in parallel: new features land on newly extracted microservices from day one, while legacy code handles the bounded contexts not yet migrated. We coordinate with your engineering manager to set branch conventions, service boundary rules, and a clear list of no-touch legacy modules so the two tracks do not collide. Typically 20–30% of the feature team’s sprint capacity is reserved for modernisation integration work; we account for that in the phase plan.

External integrations are catalogued in discovery and classified by migration risk. Integrations with documented APIs are wrapped behind an internal adapter layer first, so new microservices call the adapter rather than the legacy connector directly. End-of-life vendor APIs (for example, a deprecated SOAP endpoint) are flagged and either replaced or wrapped with a compatibility shim during migration. Integrations that cannot be replaced during migration are pinned in the legacy system and migrated last, after all other bounded contexts are live.

It happens, and we plan for it. During dual-run we run a reconciliation job that compares outputs from the legacy and new paths for every transaction. Divergences are classified into expected differences (deliberate behaviour changes), legacy bugs now surfaced, and new bugs introduced in the migrated code. Legacy bugs discovered during migration are documented and triaged with you — some are fixed in the new service, some are noted as known issues to patch post-cutover. We do not silently carry legacy bugs forward.

We define three layers of success metrics at the start: technical (test coverage, deploy frequency, MTTR, error rate on migrated services), operational (incident reduction, infrastructure cost delta, on-call burden), and business (feature velocity on the new stack, time-to-market for new capabilities). These are reported in monthly programme reviews. Each phase ends with a demoable cutover and a health dashboard showing legacy traffic percentage — so stakeholders can see the migration advancing concretely, not just on a Gantt chart.