Java development services for critical, data-intensive systems
Build new platforms, modernize existing applications and keep production systems dependable. Our engineers work across the Java stack, from data processing and integration to deployment and ongoing support.
Results from Java systems we have built
- 1,000,000,000
- financial transactions in under an hourFastPost accounting platform · developed for LegerityFastPost case study
- 300,000,000
- travel queries a dayHotel metasearch · 80% lower infrastructure costHotel search case study
- 65%
- less time to calculate flight schedulesProof of concept on production dataFlight schedule case study
Build, improve and operate your platform
New platform development
Java services for data processing, search, pricing and transaction workflows. Start with the domain model, expected workload and integration requirements.
Application modernization
Upgrade runtimes and dependencies, improve maintainability and change architecture incrementally where it helps.
Performance and scalability
Investigate bottlenecks under representative load. Improve response times, throughput or infrastructure use against an agreed baseline.
Production support
Patching, monitoring, incident handling and planned improvements, with responsibilities and service levels agreed for your environment.
The Java and Spring stack we build on
Java 21 and 25
New systems on the current long-term-support releases; existing ones on 17 or later, upgraded before support ends.
Spring Boot and Spring AI
Web services, batch, security and data access on the framework your own team can hire for, and model calls and retrieval as ordinary Spring components.
Kafka and in-memory grids
Event streaming, and Hazelcast, Oracle Coherence or Apache Ignite where throughput and latency demand them.
PostgreSQL and Elasticsearch
PostgreSQL as the default relational store, measured before any cache is proposed; Elasticsearch where search relevance matters.
Choose the engagement that fits the work
Defined projects, ongoing support or engineers joining your team. Each service has its own scope and commercial model.
| Offer | Price model | Duration | What you get |
|---|---|---|---|
| Data-intensive platform development | Time and materials with a ballpark range | Based on scope | Custom Java platforms for high-volume data processing, real-time search, pricing and analytics. |
| Application Modernization Sprint | Time and materials with a ballpark range | 6 to 12 weeks | A supported Java application baseline, with tested changes and a plan for the next phase |
| Performance Rescue | Time and materials with a ballpark range, against agreed SLO targets | 4 to 8 weeks | Measured latency and throughput improvements, with profiling evidence and validation against agreed SLOs |
| AI Integration for Java Systems | Time and materials pilot with a ballpark range; optional retainer | 4-week scoped pilot, then optional retainer | A scoped AI capability integrated with your Java application, with evaluation, access controls and a rollout decision |
| Managed Java Application Support | Monthly retainer with SLAs | Ongoing, quarterly review | Patching, dependency upgrades and a small-change budget for systems that must keep running |
| Java Team Extension | Monthly team fee | Ongoing, long-term | Senior Java engineers who join your team for the long term and bring our experience with them |
| Technical Due Diligence | Fixed fee by codebase size | 2 to 3 weeks | A written assessment of architecture, security, scalability, team and AI readiness for an investment decision |
Java engineering across complex business domains
Banking and fintech
Accounting, payments, lending and financial data platforms.
Insurance
Policy, claims and broker workflows, including Openkoda implementation and integration.
Travel
Search, pricing and availability across changing inventories.
Ecommerce
Recommendations, product information and high-volume customer journeys.
Real estate
Property data, business workflows and connected systems.
Stratoflow successfully customized the system according to the specific functionalities and without bugs reported. The team was commended for their adaptability in the work process and for their responsiveness.
Joshua BlavinsTech PM, Konekt Group
A clear scope, visible delivery and a planned handover
Understand the system
Discuss the business need and current constraints.
Agree the engagement
Set deliverables, responsibilities, acceptance criteria and the commercial model. Confirm dependencies and how scope changes will be handled.
Build with your team
Work in your repositories, share working increments and validate behavior against agreed tests and performance measures.
Handover or keep supporting
Provide documentation and knowledge transfer. Agree any ongoing maintenance, support or team-extension arrangement separately.
Before we start
Which Java technologies do you work with?
Java and Spring Boot form the core of our work, on Java 21 and 25 for new systems, with Spring AI for model integration. Depending on the system, we add Kafka, Hazelcast, Oracle Coherence, Apache Ignite, Elasticsearch and PostgreSQL. We select versions and deployment patterns around support requirements and measured needs.
Can you take over an existing application?
Yes. We first review the code, operating environment and available documentation, and agree the risks and the changes needed before we commit to delivery or support responsibilities. Evaluating a company you may acquire or invest in? A Technical Due Diligence review comes first.
How are engagements priced?
Scoped implementation projects are billed time and materials against a written ballpark estimate. Support uses a monthly retainer, and team extension uses a monthly team fee. We confirm the estimate once the scope and responsibilities are clear.
Who owns the code and works on it?
You own the commissioned code under the agreed contract, and work happens in repositories you control. Stratoflow engineers are directly employed; we do not subcontract delivery.
Do you build MVPs?
Yes, particularly for fintech and insurtech workflows that fit our Java expertise. We scope the first workflow before agreeing a build. A typical MVP engagement includes a one-week scoping phase followed by a four-week build, subject to readiness and scope.
What should we look for in a Java development company?
Evidence at your volume, and the engineers who produced it. A Java software development company should be able to show systems running under load, name who built them and say who will work on yours. As a Java application development company we build back-end platforms first: transaction processing, search, pricing and integration. We also work as a Java web development company where the platform needs portals and public APIs, but the load behind them is what we are chosen for.
Related services and guides
Discuss your Java platform
Bring the system, the constraint or the new product idea. We will help identify the right starting point and engagement model.