Your old system is
costing more than
building a new one.
We have seen what happens when teams patch a system that should have been rebuilt years ago. More patches, fewer features, slower hiring, and a growing list of things nobody wants to touch. We help you move out without breaking what is running.
"Modernizing a legacy system is not a demolition project. It is more like renovating a house while people are still living in it. You do not knock down walls. You replace them one at a time."
Every service you migrate is a wall that gets stronger without anyone noticing the work happened. The trick is sequencing. Start with the parts that are causing the most pain, build the new thing alongside the old, switch traffic over gradually, and only then tear out what you replaced. No big bang. No weekend downtime. No crossed fingers.
The system is not broken.
It just keeps getting harder.
These are the patterns we see when we first talk to an engineering team carrying a legacy system they have outgrown.
Cannot hire for the stack anymore
Nobody wants to maintain PHP 5.6 or a system with no tests and no documentation. The engineers who built it have moved on. The new ones spend weeks just understanding what they inherited.
Security vulnerabilities that cannot be patched
The framework is past end-of-life. The CVEs keep piling up. You cannot upgrade the language version without breaking something. Every month the exposure window gets wider and the fix gets harder.
Scaling hits a wall every time
Traffic spikes and the whole system struggles. You cannot scale just the parts that are under load because everything is coupled together. More hardware buys time but does not fix anything.
Fear of touching anything in production
The codebase has sections nobody understands. A change in one place breaks something else entirely. Deployments happen at 2am. Everyone holds their breath. Features take twice as long as they should.
Life before and
after the migration.
This is not a pitch for the ideal architecture. It is what we have seen change in real teams after a structured modernization programme.
We do the work.
You stay in production.
We work alongside your team, not instead of it. Everything below is something Bithost actively runs or implements as part of the engagement.
Legacy System Audit
Before anything moves, we spend time understanding what you actually have. We map dependencies, identify the riskiest parts, surface the CVEs, and produce a plain-language report on where things stand. No assumptions, no generic output.
Strangler Fig Strategy
We plan the migration using the strangler fig pattern — new services grow alongside the old system, traffic shifts gradually, and the legacy parts are decommissioned one by one. Nothing gets rewritten all at once.
Phased Migration Plan
We build a sequenced roadmap that prioritises the highest-pain services first, accounts for team capacity, and sets realistic timelines. Each phase has clear exit criteria so everyone knows when it is actually done.
Risk Assessment and Mitigation
We identify what could go wrong at each stage and build rollback procedures before they are needed. Every service migration includes a parallel-run period where both versions are live and we can switch back in under a minute.
Zero-Downtime Deployment Strategy
We implement blue-green or canary deployment pipelines before the first service migrates. By the time production traffic moves, the deployment process has already been tested dozens of times in staging.
Cloud Migration and Infra Setup
If the move to cloud is part of the plan, we handle the infrastructure side — Kubernetes, Terraform, CI/CD pipelines, environment parity. We set it up right the first time rather than retrofitting later.
Tech Debt Triage and Remediation
Not every piece of legacy code needs a full rewrite. We distinguish between the technical debt that is actively slowing you down and the debt that is stable and can wait. We tackle the first kind and document the second.
Knowledge Transfer Throughout
We document as we go, hold working sessions with your team, and make sure the engineers who will own the new system understand every decision we made. The goal is that we eventually become unnecessary.
From audit to
decommissioned legacy.
System audit and risk map
We spend one to two weeks reading your codebase, interviewing your engineers, and mapping every dependency and vulnerability. The output is a risk-ranked inventory of what needs to move, in what order, and why.
Migration roadmap and tooling setup
We deliver the sequenced migration plan, set up the deployment pipeline, establish the parallel-run infrastructure, and instrument both the old and new systems with the monitoring needed to make safe traffic shifts.
Service-by-service migration
We rebuild and migrate one service at a time, running old and new in parallel until the new version proves itself. Traffic moves in increments — 10%, 30%, 70%, then 100%. If something looks wrong we roll back before users notice.
Legacy decommission and handover
Once traffic is fully on the new stack and the stability window closes, we decommission the old services, archive what needs to be kept, and hand the system to your team with documentation and a runbook for everything we built.
14 CVEs identified. PHP 5.6 reached end-of-life in December 2018. No security patches available. Framework version pinned due to tight coupling with deprecated APIs.
Auth migrates first. It has the most CVEs, is the most self-contained service, and unblocking it frees up the framework upgrade for everything downstream. Estimated 6 weeks including parallel run.
Canary performing well. Error rate 0.02% vs 0.18% on legacy. P99 latency 142ms vs 380ms. Safe to increase traffic weight to 50% this week.
Legacy decommissioned. All traffic running on the new stack for 30 days with no incidents. The old system has been archived and the infrastructure costs dropped by 40%.
What the numbers
tend to look like.
These are representative figures from modernization engagements in the 50 to 500 person range. Every situation is different and we will give you honest estimates based on your actual system.
Things people
ask us right away.
Not sure where to start?
Start with the audit.
A free 30-minute call is enough to understand your current system, identify the biggest risks, and tell you whether a structured modernization programme makes sense for your situation.
Book a free system audit call
Your old system is
costing more than
building a new one.
We have seen what happens when teams patch a system that should have been rebuilt years ago. More patches, fewer features, slower hiring, and a growing list of things nobody wants to touch. We help you move out without breaking what is running.
"Modernizing a legacy system is not a demolition project. It is more like renovating a house while people are still living in it. You do not knock down walls. You replace them one at a time."
Every service you migrate is a wall that gets stronger without anyone noticing the work happened. The trick is sequencing. Start with the parts that are causing the most pain, build the new thing alongside the old, switch traffic over gradually, and only then tear out what you replaced. No big bang. No weekend downtime. No crossed fingers.
The system is not broken.
It just keeps getting harder.
These are the patterns we see when we first talk to an engineering team carrying a legacy system they have outgrown.
Cannot hire for the stack anymore
Nobody wants to maintain PHP 5.6 or a system with no tests and no documentation. The engineers who built it have moved on. The new ones spend weeks just understanding what they inherited.
Security vulnerabilities that cannot be patched
The framework is past end-of-life. The CVEs keep piling up. You cannot upgrade the language version without breaking something. Every month the exposure window gets wider and the fix gets harder.
Scaling hits a wall every time
Traffic spikes and the whole system struggles. You cannot scale just the parts that are under load because everything is coupled together. More hardware buys time but does not fix anything.
Fear of touching anything in production
The codebase has sections nobody understands. A change in one place breaks something else entirely. Deployments happen at 2am. Everyone holds their breath. Features take twice as long as they should.
Life before and
after the migration.
This is not a pitch for the ideal architecture. It is what we have seen change in real teams after a structured modernization programme.
We do the work.
You stay in production.
We work alongside your team, not instead of it. Everything below is something Bithost actively runs or implements as part of the engagement.
Legacy System Audit
Before anything moves, we spend time understanding what you actually have. We map dependencies, identify the riskiest parts, surface the CVEs, and produce a plain-language report on where things stand. No assumptions, no generic output.
Strangler Fig Strategy
We plan the migration using the strangler fig pattern — new services grow alongside the old system, traffic shifts gradually, and the legacy parts are decommissioned one by one. Nothing gets rewritten all at once.
Phased Migration Plan
We build a sequenced roadmap that prioritises the highest-pain services first, accounts for team capacity, and sets realistic timelines. Each phase has clear exit criteria so everyone knows when it is actually done.
Risk Assessment and Mitigation
We identify what could go wrong at each stage and build rollback procedures before they are needed. Every service migration includes a parallel-run period where both versions are live and we can switch back in under a minute.
Zero-Downtime Deployment Strategy
We implement blue-green or canary deployment pipelines before the first service migrates. By the time production traffic moves, the deployment process has already been tested dozens of times in staging.
Cloud Migration and Infra Setup
If the move to cloud is part of the plan, we handle the infrastructure side — Kubernetes, Terraform, CI/CD pipelines, environment parity. We set it up right the first time rather than retrofitting later.
Tech Debt Triage and Remediation
Not every piece of legacy code needs a full rewrite. We distinguish between the technical debt that is actively slowing you down and the debt that is stable and can wait. We tackle the first kind and document the second.
Knowledge Transfer Throughout
We document as we go, hold working sessions with your team, and make sure the engineers who will own the new system understand every decision we made. The goal is that we eventually become unnecessary.
From audit to
decommissioned legacy.
System audit and risk map
We spend one to two weeks reading your codebase, interviewing your engineers, and mapping every dependency and vulnerability. The output is a risk-ranked inventory of what needs to move, in what order, and why.
Migration roadmap and tooling setup
We deliver the sequenced migration plan, set up the deployment pipeline, establish the parallel-run infrastructure, and instrument both the old and new systems with the monitoring needed to make safe traffic shifts.
Service-by-service migration
We rebuild and migrate one service at a time, running old and new in parallel until the new version proves itself. Traffic moves in increments — 10%, 30%, 70%, then 100%. If something looks wrong we roll back before users notice.
Legacy decommission and handover
Once traffic is fully on the new stack and the stability window closes, we decommission the old services, archive what needs to be kept, and hand the system to your team with documentation and a runbook for everything we built.
14 CVEs identified. PHP 5.6 reached end-of-life in December 2018. No security patches available. Framework version pinned due to tight coupling with deprecated APIs.
Auth migrates first. It has the most CVEs, is the most self-contained service, and unblocking it frees up the framework upgrade for everything downstream. Estimated 6 weeks including parallel run.
Canary performing well. Error rate 0.02% vs 0.18% on legacy. P99 latency 142ms vs 380ms. Safe to increase traffic weight to 50% this week.
Legacy decommissioned. All traffic running on the new stack for 30 days with no incidents. The old system has been archived and the infrastructure costs dropped by 40%.
What the numbers
tend to look like.
These are representative figures from modernization engagements in the 50 to 500 person range. Every situation is different and we will give you honest estimates based on your actual system.
Things people
ask us right away.
Not sure where to start?
Start with the audit.
A free 30-minute call is enough to understand your current system, identify the biggest risks, and tell you whether a structured modernization programme makes sense for your situation.
Book a free system audit call