Application modernization services, one manageable step at a time
Improve performance, maintainability and supportability through incremental upgrades. After a scoping call you get a written ballpark within a week; the first iteration maps the code and confirms the plan.
Results from systems we have built and improved
A modernization we finished this year, and the platform work behind it: architecture redesign, performance engineering and long-term development on systems that stayed in production throughout.
- 47 to 0
- critical and high-severity advisories cleared from a fifteen-year-old Java commerce platform, moved to Java 25 and Spring 6 in about four weeks with no rewrite.Wine merchant modernization case study
- 80%
- lower infrastructure cost after extracting hotel availability search into an in-memory data grid; the database remained the system of record.Hotel metasearch case study
- 1B / hour
- financial transactions on FastPost, built and evolved by Stratoflow for nearly ten years from 2013.FastPost case study
The developed software product was built from scratch with solid quality. We have had a long-term engagement with Stratoflow for nearly 10 years. We look at them as partners, rather than contractors. I'm impressed by their team culture and cross-team support.
- Starting point
- A scoping call, then a written ballpark within a week.
- First iteration
- Maps the application, runtime and dependencies and confirms the plan for the phase.
- Implementation
- Plan for 6 to 12 weeks per agreed phase.
- Commercial model
- Time and materials against an agreed scope, with a ballpark estimate.
Address the parts of your application that hold it back
The first iteration identifies which changes matter first. A phase can cover one of these areas or a combination, depending on dependencies and the outcome you need.
Java and Spring upgrades
Move to a supported runtime and framework baseline. Check library compatibility, build tooling and behaviour changes before choosing the target versions. Add regression tests around the functions the business relies on.
Dependencies and security
Map the dependency tree, identify known vulnerabilities and plan upgrades or replacements. Record any remaining issues and the decisions needed to address them, including dependencies that no longer have a supported release.
Architecture and performance
Find the boundaries that let a part of the application change independently. Measure bottlenecks before choosing whether to refactor code, change data access or extract a component. A modular monolith may remain the right architecture.
Data and integrations
Plan schema changes, data backfills and interface updates alongside the application changes. Check compatibility with systems that must continue running, and define how data will be verified during rollout.
Deployment and observability
Improve the build and release path, environment configuration, logs, metrics and traces. Define the checks that show a release is healthy and the rollback steps the team will use if it is not.
Cloud infrastructure
Assess whether a cloud move supports the business case. Compare operating costs, measure resource needs and choose infrastructure around the workload. The migration plan includes the application, its data and its external dependencies.
Agree the next step before committing to the whole programme
Discuss the application
On the scoping call, review the current stack, business priorities, known problems and delivery constraints. A written ballpark follows within a week, with the access and people the work needs.
Map and plan
In the first iteration, review the code, dependencies, runtime behaviour, tests and deployment process. Identify a first group of related components that can be changed together, and confirm the roadmap, risks and plan for the phase.
Implement and verify
Work in weekly iterations within the agreed scope. Establish baseline behaviour, make the changes and check them against agreed acceptance criteria. Review progress with your team every week and agree any scope changes before carrying them out.
Roll out and hand over
Choose a rollout approach around the application and its integrations. Rehearse data migration and rollback where applicable, agree any maintenance window, and hand over code, documentation and operational guidance. Use what was learned to plan the next phase.
What each phase delivers
The first iteration is part of the phase, not a separate engagement. You keep its findings and roadmap whether you continue with us or plan the work with your own team.
First iteration: findings and roadmap
A view of the current versions, dependencies, test coverage and operating constraints. Prioritized changes, migration boundaries, risks and a recommended order of work.
First iteration: plan for the phase
The scope, assumptions, acceptance criteria and schedule for the rest of the phase, checked against the ballpark. A list of the access, decisions and support needed from your team.
Implementation: code and validation
The agreed application changes, tests and build or deployment updates. Documentation of behaviour changes, validation results and any remaining issues that need a decision.
Implementation: handover and next steps
Operational notes, rollout and rollback instructions where applicable, and knowledge transfer. A delivery report covering the agreed measures and recommendations for the next phase.
An estimate for the work you agree to undertake
The first phase is billed time and materials against the written ballpark you receive after the scoping call. Its first iteration confirms the scope; if the findings change the ballpark, we say so before the work continues. You approve each phase separately.
The estimate depends on the components being changed, test coverage, the runtime and framework upgrade path, data migration, external integrations and operating constraints. These factors also determine whether a phase fits the usual 6 to 12 week planning range. An application may need several phases; the first one establishes their sequence and an initial programme estimate.
The phase plan defines the included work, acceptance criteria and assumptions. If new findings or a requested change affect that scope, we discuss the impact and agree the price and schedule before proceeding with the additional work. Results from completed phases help refine later estimates.
When one engineering decision needs attention first
Architecture
Evaluate whether to separate services, improve module boundaries or retain the current structure.
Delivery platform
Review build pipelines, environments and the infrastructure your developers use to release software.
Cloud migration
Assess the operating model, workload and costs before choosing a migration approach.
Vulnerability remediation
Address dependency findings with a prioritized upgrade plan and a record of remaining risks.
Planning a Java modernization project
How long will the whole project take?
A scoped phase is usually planned for 6 to 12 weeks, starting with an iteration that maps the application. The total depends on the number of phases, their dependencies, testing, data migration and release windows. The first iteration gives an initial estimate for the programme, refined as work progresses. Parallel work is possible where components and team capacity allow it.
Will migration require downtime?
That depends on the application, its data and connected systems. Parallel operation and staged cutovers can reduce disruption, but some changes require a maintenance window. We identify these constraints in the first iteration and agree the rollout, validation and recovery plan with your team.
Which Java and Spring versions should we target?
We choose supported versions that fit your libraries, deployment environment and maintenance requirements. Java 21 or 25 may be suitable targets; Spring Boot 4 requires Java 17 or later. A framework minimum is only one input to the decision. The first iteration checks compatibility and the upgrade path for your application.
What if the application has few tests or little documentation?
We include discovery and characterization tests in the scope where they are needed. These tests capture important existing behaviour before changes begin. Access to people who understand the business workflows helps identify which behaviours must be preserved and which can change.
Do we need microservices or a complete rewrite?
Neither is a default requirement. Improving a modular monolith may be sufficient. Where components can be separated safely, incremental replacement can reduce the amount of change in each release. A replacement may be appropriate when the existing system cannot meet future needs at a reasonable cost. We compare the options in the first iteration, or in a separate architecture review if you want that decision first.
Can you take over an application built by another vendor?
Yes. We start by establishing the code, infrastructure, access and knowledge available to your team. Gaps in documentation, tests or ownership become explicit findings of the first iteration and are reflected in the delivery plan. If you are buying or investing in the company behind the system, start with Technical Due Diligence.
How do you use AI during delivery?
We use a sanctioned toolchain within client-approved data boundaries for tasks such as characterization tests, dependency upgrades and migration scaffolding. Tool use is agreed around your environment and requirements.
What happens after the final phase?
We hand over the agreed documentation and operational knowledge to your team. If you need ongoing patching, maintenance or application support, we can discuss a separate managed support engagement.
How do you approach legacy application modernization?
From the running system rather than a rewrite plan. Many legacy modernization services begin with a replacement; ours begin with what the application does today. Our legacy system modernization services upgrade Java and Spring, replace unsupported libraries, add tests where changes land and extract parts only where it pays, often with the strangler pattern, while releases continue.
How should we compare application modernization companies?
Ask each application modernization company three things: whether the engineers in the pitch will do the work, how releases continue while the upgrade runs, and what you hold at the end. The answers separate application modernization companies that sell a rewrite from those that leave you with a supported system you can change.
Plan the next step for your Java application
Tell us what is running today, what needs to improve and the constraints you need to work within. A written ballpark follows within a week.