Your Legacy System Replaced.
Zero Downtime. No Big-Bang Rewrite.
Your legacy system costs your team hours every sprint. Deployment weekends, blocked features, and workarounds compound quietly. We replace legacy applications using the strangler fig pattern. Components migrate one at a time. Your users never notice. Your team never misses a release.
The overhead your team pays every sprint. What engineering looks like after we modernize your system.
Every line on the left has a dollar amount on it. The right column is what your team gets back when that overhead is gone.
Pain · IT team at legacy server maintenance
Your legacy system is billing your team by the hour. See the running tab.
Enter your team size, overhead percentage, and developer rate. The counter above runs in real time. Watch what your legacy system costs before you finish reading this page.
*Formula: developers × overhead % × rate × 40 hrs × 52 wks. Excludes infrastructure, security incidents, and recruiting costs.
Get A Modernization ProposalMost modernization projects recoup their cost within 18 months. By year two, the eliminated overhead exceeds the one-time engagement cost. Use your numbers above to size the return for your organization.
See your scoped proposal with line-by-line pricing →Five phases. No launch weekends. No user disruption from phase one to handoff.
Every phase delivers independently. If a phase pauses, the prior phase keeps running in production. No phase gates the next one.
We audit the full codebase, map every integration, scan for security vulnerabilities, and document all data flows. Every risk gets a severity ranking before we write a line of code.
We finalize the migration roadmap, design the adapter layer, and build the CI/CD pipeline. The modern environment starts receiving shadow traffic before any service migration begins.
We replace legacy components one service at a time. Each new service goes live in production before the next migration starts. The legacy system keeps serving everything not yet migrated.
We run parallel writes to both databases and validate data consistency at each step. Load tests run against production data volumes. We do not cut over until the new database proves itself under real conditions.
We route the last traffic away from the legacy system after final validation. You receive architecture diagrams, runbooks, on-call playbooks, and a data model guide. The 90-day hypercare period begins. Full IP transfers to your team.
The strangler fig pattern: how traffic moves from legacy to modern with zero downtime
Click any layer to see what it handles, what it protects, and how it behaves during migration. Any layer can be replaced without taking the others offline.
The legacy system runs at 100% of production traffic on day one. It is never shut down. Components are extracted one at a time. The legacy system keeps serving everything not yet migrated. When migration is complete, traffic drops to zero and the system is decommissioned cleanly.
The adapter layer intercepts every request and sends it to either the legacy system or the modern platform, depending on whether that route has migrated. It handles protocol translation between old and new systems during parallel writes. It provides instant rollback at any point in the migration.
The modern platform receives real production traffic the moment the first service migrates. Not staged traffic. Not synthetic load tests. Real users, real data, real conditions. By the time the legacy system's traffic reaches zero, the modern platform has been running in production for weeks. Failure modes have already been surfaced and resolved. The final cutover is not a risk event. It is the confirmation of something already working.
Legacy monolith replaced. Zero user disruptions. Continuous deployments from week one post-launch.
Proof · post-modernization launch milestone
A mid-market SaaS platform serving thousands of active users. The legacy monolith powered core product features and processed real-time data at scale. Tightly-coupled architecture had accumulated over years. Any migration that risked user disruption or data loss was not an option.
The monolith caused slow release cycles, production outages under load, and architecture that made independent team deploys impossible. Every deployment required manual coordination. The system could not keep pace with user growth.
- Cloud-native microservices on Kubernetes (AWS EKS)
- CI/CD pipeline replacing manual deployment processes
- Zero production user disruptions during full migration
- Containerized services with auto-scaling and self-healing
Three things that separate a real legacy application modernization agency from a very expensive weekend outage.
A big-bang rewrite means taking a production system offline, building a replacement in isolation, and launching it cold. Most big-bang rewrites fail, cause outages, or deliver a platform that cannot handle real production load. The strangler fig pattern replaces one service boundary at a time. The legacy system keeps serving production traffic throughout. There is no moment where everything is offline. There is no single cutover that can fail. There is always a working rollback.
The modern platform receives real production traffic from the moment the first service migrates. Not staged traffic. Not synthetic tests. Real users. By the time the legacy system's traffic reaches zero, the modern platform has already been running in production for weeks. Failure modes have surfaced and been resolved. The cutover formalizes something already working — it is not a risk event.
Enterprise software servicesNo licensing. No proprietary tooling your team cannot read. No ongoing dependency on us to make changes. The code ships with architecture diagrams, runbooks, on-call playbooks, and a data model guide. Any engineer you hire can understand the system on day one. The 90-day hypercare window is support, not a subscription. When it ends, your team owns and runs the platform. That is what we are building toward.
Custom software developmentWhat CTOs and engineering leads ask before engaging.
How long does legacy application modernization take?
Legacy application modernization typically runs 16 to 28 weeks depending on system complexity, integration surface, and migration approach. Every engagement starts with a two to three week technical audit that maps the full system before any build work begins. The audit produces a risk-ranked migration plan with a phase-by-phase timeline. For more complex systems or larger codebases, phased programs may run 12 to 18 months across multiple increments.
Do we need to shut down the legacy system during modernization?
No. The strangler fig pattern allows the modern platform to replace legacy components incrementally while the legacy system continues to serve production traffic. Your users never experience downtime. The legacy system is decommissioned only after the modern platform has proven itself in production, not before. See our cloud-native development services for the architecture that makes this possible.
What happens to existing data during the migration?
We plan data migration in the architecture phase, before any code is written. We design the data pipeline alongside the new system schema. We run parallel writes to both databases during the transition. We validate data consistency at every phase. We do not cut over until the new database proves itself against production data volumes. Data migration is never a big-bang event. It is a continuous, validated handoff.
How do you handle existing integrations and third-party systems?
We map every integration in the technical audit. Each one connects through an adapter layer in the new architecture, so the modern system can communicate with legacy integrations during transition. Each integration migrates on its own timeline. A delay in one never blocks the rest of the project. Deprecated integrations are documented and their replacements planned before migration begins — not discovered mid-build.
What does legacy application modernization pricing look like?
Legacy application modernization typically runs between $120,000 and $500,000 depending on system complexity, codebase age, integration surface, and migration strategy. We scope before we quote. Every proposal includes a line-by-line breakdown with phase-by-phase pricing and clear scope boundaries. The technical audit (weeks 1 to 3) is priced separately and produces the migration plan that informs the full engagement cost. Book a call and we will send you a scoped proposal within 3 business days.
We tell you directly whether this engagement fits before you commit.
Not sure? Tell us about your system and we will tell you honestly whether modernization makes sense right now.
Tell us about your legacy system. We will tell you exactly what modernization would involve.
Every brief gets a response within two business days. No commitment. No pitch. Just an honest technical assessment.
Submit brief → call within 48 hours → audit scoped in 3 days → audit starts within 1 week
We will review your system and send a scoped proposal with phase-by-phase pricing within 3 business days.
Pre-footer · lead architect at new modern architecture
No commitment. No pitch.