Track 02 · Full-stack Java
Spring Boot API development and integrations
Backends your team can read, test and change without fear.
Overview
Overview
ByteKnot Labs builds the APIs and integrations businesses run on: REST and GraphQL APIs on Java and Spring Boot, authentication and authorisation with Spring Security, MySQL schemas designed for growth, and integrations with ERPs, CRMs, payment providers, messaging and partner systems, with retries, idempotency and an audit trail. Everything arrives tested, containerised and documented with an OpenAPI specification.
REST · GraphQL · webhooks · integrations
You probably need this if
- Your web and mobile apps each reach into the database in their own way.
- Partners keep asking for an API you do not have.
- Integrations break silently and someone finds out from a customer.
- Deployments are manual and happen on Friday nights.
Approach
How we build it.
- 01
Contract first
We agree the API contract and the schema before writing services, and generate the OpenAPI specification from the code so it never drifts.
- 02
Tests around what we touch
On existing code we add integration tests around a module before changing it, so every change is safe to ship.
- 03
Failures you can see
Retries, dead-letter queues and alerts on every integration, so a failed message becomes a ticket, not a surprise from a customer.
- 04
Operable from day one
Container images, health checks, structured logs, traces and a CI pipeline, so your team can run it without us.
Deliverables
What you get.
- Domain model and API design with an OpenAPI specification
- Spring Boot services with Spring Security, JPA and Flyway
- MySQL schema design, indexing and query tuning
- Integrations with payments, ERP, CRM, messaging and webhooks
- Webhooks, retries, idempotency keys and an audit trail for every integration
- Background jobs, queues and event-driven pipelines
- Test suites, CI pipelines and container images
Stack
What we build it with.
Chosen per project, benchmarked where it matters, and all of it something your team can run after us.
- Java 21 / 25 LTS
- Spring Boot 4
- Spring Security
- Spring Data JPA
- Flyway
- MySQL 8.4 / 9.7 LTS
- Redis
- Kafka
- Pub/Sub
- OpenAPI
- GraphQL
- JUnit 5
- Testcontainers
- Docker
- Kubernetes
Typical builds
What this looks like in practice.
Core API for a SaaS product
Multi-tenant, secured and documented, ready for web and mobile clients.
Integration layer
One place where internal systems and partners exchange data, with retries and an audit trail.
Partner API
A documented, versioned API your partners can build against, with keys, rate limits and usage reporting.
Backend for an AI product
The secure, typed API layer an AI-native product needs underneath it.
How a project runs
Process
Discover, then Design, then Build, then Launch and hand over. A working build every week, on a staging environment in your cloud.
How a project runsTerms
Code in your GitHub, infrastructure in your cloud, nothing trained on your data, and everything yours when we leave.
Read the termsFAQ
APIs and integrations: questions
Last reviewed
Why Spring Boot rather than Node.js or Python?
For long-lived systems with complex business rules, Spring Boot gives strong typing, a proven security stack and predictable operations. We use Node.js and Python where they fit better, such as web front ends and model serving.
REST or GraphQL?
REST for most business APIs and anything partners consume, because it is simple to cache, secure and document. GraphQL when several front ends need different shapes of the same data. Both can run on the same Spring Boot service.
How do you stop integrations failing silently?
Every integration gets retries with back-off, a dead-letter queue, idempotency keys so a retry never charges twice, an alert when something fails, and an audit trail of what was sent and received.
Can you work on our existing Java codebase?
Yes. We start with a review, add tests around the parts we touch, and change it in small, releasable steps. If it is on an old Java or Spring Boot version, see our Java and Spring Boot modernisation service.
Can we hire a dedicated Spring Boot engineer from you?
Yes, as an ongoing team: a retained engineer or small team, billed monthly, with a notice period and no long contract.
Do you handle database migrations and performance?
Yes. Schema changes ship as versioned Flyway migrations, and we profile and tune MySQL queries and indexes as part of delivery.
Further reading
Before you decide.
Often paired with
CRMs and ERPs
Custom CRMs, ERPs, portals and back-office systems on Java, Spring Boot and MySQL.
ExploreJava modernisation
Legacy Java and Spring Boot moved to supported versions in small, tested steps, without a rewrite.
ExploreTaking on new projects
Planning work on APIs and integrations? Let's talk.
A short call, a written brief, and a straight answer on scope, price and timeline before any work starts. NDA first if you need one.