Security & App Store Risk
EOL frameworks receive zero patches. Legacy iOS apps built on deprecated APIs get rejected at review — every month of delay expands attack surface and blocks releases.
Legacy Modernization Services
Legacy Application Modernization Services.
Legacy modernization services with zero downtime — monolith to microservices, on-prem to cloud, Oracle to PostgreSQL, and legacy iOS apps rebuilt to current App Store requirements.
- 120+
- Systems Modernized
- 99.9%
- Uptime During Migration
- 60%
- Avg Cost Reduction
- 4.9★
- Client Rating
- NDA signed on day one
- Fixed-price quote within 48 hours
- Senior engineers only, in your timezone
- You own the code and IP
Get your custom project plan
Share your project details — a senior engineer responds within 4 hours.
NDA protected 24hr response Free consultation
Independently audited, certified and built to standards you can check
Legacy application modernization services move ageing systems onto supported stacks without stopping the business. Codazz replatforms monoliths to cloud, migrates Oracle and SQL Server databases, wraps legacy APIs, and provides legacy iOS modernization development services for Objective-C and Swift apps that fail App Store review — incrementally, with rollback at every step.
Clutch Top Modernization Company 2026AWS Migration CompetencySOC 2 Type II CertifiedISO 27001 CertifiedAzure Migration PartnerGoogle Cloud PartnerTop IT Services - GoodFirmsZero-Downtime Track Record
Why Legacy Systems Need Modernization Now
Maintenance Cost Spiral
Legacy code costs 3–5× more to maintain than modern equivalents. Vendor lock-in, custom patches and shrinking talent pools drain engineering budgets every quarter.
Integration Bottlenecks
Systems never designed for APIs turn every new partner integration into a multi-month project instead of a REST call.
Who Needs Legacy Modernization?
Financial Services
COBOL mainframes, monolithic banking apps and legacy trading platforms that cannot meet modern regulatory or API requirements.
Healthcare
Legacy EHR systems, HIPAA gaps and on-prem medical databases that need cloud migration without disrupting patient care.
Manufacturing & Enterprise
Ageing ERP systems and custom inventory platforms costing millions in maintenance and unplanned downtime.
Retail & Mobile-First Brands
Monolithic platforms and legacy iOS apps struggling with traffic spikes, slow releases and outdated payment integrations.
Modernization Impact
60-80%
Cost Reduction
Infrastructure savings
4-5x
Developer Productivity
Features per quarter
99.9%
Uptime
Post-modernization
80-95%
Fewer Incidents
Security improvements
75%
Faster Hiring
Modern stack appeal
10x
Faster Deploys
Monthly to daily
Legacy modernization is a business transformation, not a tech refresh. Codazz uses strangler-fig patterns and blue-green deployments to migrate incrementally — zero downtime, rollback at every phase, and measurable improvements within weeks.
How We Modernize
Legacy Modernization Services Zero-downtime guaranteed.
From re-platforming and refactoring to full rebuilds and API-first modernization — we choose the right approach for each component of your system.
Monolith to Microservices
Decompose tightly coupled monoliths into independently deployable microservices using the strangler-fig pattern — no big-bang rewrites, no downtime.
Domain-DrivenEvent-DrivenAPI GatewayService Mesh
On-Prem to Cloud
Migrate from physical data centers to AWS, Azure, or GCP with infrastructure-as-code, containerization, and cost optimization from day one.
AWSAzureGCPDockerKubernetesTerraform
Database Migration
Move from legacy databases — Oracle, SQL Server, MySQL on-prem — to modern managed solutions with zero data loss and schema optimization.
PostgreSQLMongoDBDynamoDBAuroraCloud SQL
API-First Modernization
Wrap legacy systems with modern RESTful and GraphQL APIs so they can integrate with any modern tool, partner, or platform.
RESTGraphQLAPI GatewayOAuth 2.0OpenAPI
Replatform & Refactor
Move existing applications to modern infrastructure with minimal code changes, or incrementally restructure for better performance and maintainability.
Lift & ShiftContainersCI/CDBlue-Green Deploy
Explore GreenfieldFull Rebuild
Build completely new applications using modern frameworks and cloud-native architecture while preserving business rules, data models, and workflows.
ReactNode.jsGoCloud-NativeMicroservices
Explore 
Why Codazz Modernization
Modernization That Protects Your Business.
Every legacy modernization engagement is scoped, priced and staffed the same way — so these hold on every project, not just the showcase ones.
Zero-Downtime Guarantee
Strangler-fig patterns and blue-green deployments keep your business running at full capacity throughout the entire migration.
Data Integrity First
Parallel environments, real-time syncs and reconciliation reports before every cutover — no big-bang migrations.
Knowledge Transfer Built In
Architecture decision records, runbooks and hands-on training included so your team owns the modernized system.
Trusted by teams building with
AWSAzureGoogle CloudDockerKubernetesTerraformPostgreSQLMongoDBRedisKafkaDatadogPagerDutyGitHubGitLabNew RelicGrafana
By the numbers
Legacy Modernization Results That Speak for Themselves.
120+Systems ModernizedAcross industries
99.9%UptimeDuring migration
60%Cost ReductionAverage savings
10xFaster DeploysPost-modernization
4.9★Client RatingAcross 70+ reviews
How we deliver legacy modernization projects
One process, five stages, fixed milestones. You always know what is happening and what it costs.
- 01
Discovery
1–2 weeksWe map the business problem, the users and the constraints, then agree what success looks like in numbers.
Scope documentFixed-price quote - 02
Design & architecture
2–4 weeksFlows, interface design and a clickable prototype, so the hard decisions are settled before engineering starts.
Clickable prototypeTechnical architecture - 03
Build
8–16 weeksTwo-week sprints against a fixed scope. You see working software every fortnight, not a status report.
Sprint demosAutomated tests - 04
Launch
1–2 weeksLoad testing, security review, migration and a rollout plan — with someone from the build team on call.
Security reviewRollout plan - 05
Support & scale
OngoingMonitoring, iteration and a support SLA. Most clients keep building with us long after go-live.
MonitoringSupport SLA
Advanced technologies
Modernization Technologies Built Into Every Migration.
We do not just build products — we engineer intelligent, connected, future-proof digital experiences.
Strangler Fig Pattern
Incremental migration without downtime or risk
Containerization
Docker and Kubernetes for portable, scalable workloads
Infrastructure as Code
Terraform and Pulumi for reproducible environments
Blue-Green Deploys
Zero-downtime deployments with instant rollback
Observability
Full-stack monitoring with Datadog and Grafana
Zero Trust
Modern security architecture for cloud-native apps
Event Sourcing
Event-driven architecture for microservices communication
Data Pipelines
ETL and real-time streaming for data migration
Canary Releases
Gradual traffic shifting for safe deployments
API Gateway
Kong, AWS API Gateway for service orchestration
Service Mesh
Istio and Linkerd for microservice communication
Serverless
AWS Lambda and Cloud Functions for event-driven workloads
Technology stack
Legacy Modernization Stack. 40+ Migration Tools.
Best-in-class tools chosen for performance, reliability, and long-term maintainability.
Backend
Node.jsPythonGo.NET CoreJava (Spring Boot)RustFrontend
ReactNext.jsTypeScriptVue.jsAngularCloud & DevOps
AWSAzureGCPDockerKubernetesTerraformDatabases
PostgreSQLMongoDBDynamoDBRedisElasticsearchMessaging & Events
KafkaRabbitMQSQS/SNSEventBridgeMonitoring
DatadogGrafanaPrometheusNew RelicPagerDuty
Selection guide
How to Choose a Legacy Modernization Company
Choosing the right modernization partner is critical — one wrong migration can mean data loss or extended downtime.
Proven Portfolio
Look for references with measurable results in monolith-to-microservices, cloud migration, and zero-downtime cutovers.
Senior Engineers
8+ years avg experience. AWS/Azure/GCP, Docker, Kubernetes, Terraform, and legacy stack familiarity (COBOL, .NET, Java).
Fixed-Price Quotes
No hourly surprises. Clear scope with phased milestones, rollback procedures, and data validation checkpoints.
Post-Launch SLAs
Maintenance, monitoring, incident response, and uptime guarantees for modernized systems.
Security Certs
SOC 2, ISO 27001, HIPAA, PCI-DSS compliant. Zero-trust architecture and encrypted data migration.
Your Timezone
Dedicated PM, daily standups, sprint demos, and stakeholder alignment meetings.
“Scaling to 500K concurrent users was a non-event with their architecture. Black Friday, not a single crash. I’m never going anywhere else.”
Alex R.Founder, E-Commerce Platform, New York
500Kconcurrent users
Frequently asked questions
Answers to common questions about legacy iOS modernization, cloud migration, monolith decomposition and enterprise system transformation.
Ask our teamLegacy iOS modernization development services rebuild or replatform ageing iPhone and iPad apps — Objective-C to Swift, unsupported SDKs to current APIs, monolithic backends to cloud-native services — so the product passes App Store review and runs on supported iOS versions. The work is delivered incrementally with parallel environments and rollback at every cutover.
A targeted re-platform of one application takes 8–16 weeks. A full monolith-to-microservices programme for an enterprise system runs 6–18 months with phased rollouts. Every engagement starts with a 2–4 week assessment and pilot so you see working software before committing to the full scope.
Yes. We use strangler-fig patterns, blue-green deployments and incremental migration strategies that keep your existing system running while we build and cut over to the modernized version. Zero-downtime migration is a core requirement in every project we take on.
Cost depends on system complexity, component count, migration strategy and timeline urgency. A single-app re-platform sits at one end; a multi-system enterprise programme with change management at the other. We provide a cost-benefit analysis during assessment and a fixed-price quote with phased milestones before development starts.
Re-platforming moves your application to new infrastructure (e.g., cloud) with minimal code changes. Refactoring restructures the internal codebase for better performance and maintainability. Rebuilding means creating a new application from scratch using modern architecture while preserving business logic and data.
We audit the existing Objective-C or Swift codebase, map deprecated APIs to current equivalents, migrate UIKit screens to SwiftUI where appropriate, update push notification and background-task entitlements, and run TestFlight builds against Apple's latest review guidelines before submission. Backend APIs are wrapped or replaced in parallel so the app never loses data connectivity during the transition.
No. Data integrity is non-negotiable. We run parallel environments, perform incremental data syncs and execute comprehensive validation checks before any cutover. Every migration includes rollback procedures and data reconciliation reports.
From our blog
View all articlesLegacy Modernization Insights & Guides.
Blog
Monolith to Microservices: A Step-by-Step Guide
How to decompose a monolithic application into microservices without downtime.
Read article BlogCloud Migration Cost Calculator: What to Expect
Budgeting guide for migrating from on-prem to AWS, Azure, or GCP.
Read article BlogThe Strangler Fig Pattern Explained
The safest approach to legacy modernization — incremental migration without risk.
Read articleExplore
Related services and the industries we serve most often.
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Industries we serve
Let’s build something worth keeping.
Tell us what you are trying to build. A senior engineer will come back within one working day with a scope, a timeline and a fixed price.