A backend for an Android application or web system.
Backend systems and integrations
Backend systems and integrations for applications and business processes
I build backend services, REST APIs and data flows that fit the product, existing systems and the way the team works. I can deliver a new service or take responsibility for a focused module in an existing solution.
I work on complete backends for first product versions as well as isolated integrations, authorization modules and synchronization workflows.
When this service is a good fit
A backend should solve a defined product problem rather than simply expose more endpoints.
- You are building a mobile or web application and need a stable API.
- The current backend slows down feature development or one area needs to be restructured.
- Several systems, a payment provider, marketplace or another external API must be connected.
- The product needs data synchronization, webhooks, scheduled jobs or background processing.
- A service needs to be prepared for predictable deployment and continued maintenance.
What the work can include
The scope depends on the product stage. Not every project needs extensive infrastructure immediately, but every project benefits from clear boundaries and an intentional growth path.
- Analysis of the domain, data flows and system responsibilities.
- REST API design, data models, validation and error handling.
- Authentication, authorization, roles and secure access management.
- External service integrations, webhooks and retry mechanisms.
- Data synchronization, scheduled tasks and background processes.
- Unit and integration tests together with API documentation.
- Containerization and deployment-ready configuration.
Example solutions
Connecting an online store or internal system with an external platform.
User accounts, permissions and organization management.
Synchronization between an application, database and external services.
A service that imports, normalizes or periodically processes data.
How the collaboration works
We first define the backend responsibility and its contracts with the rest of the product. Implementation starts once the required data and processes are understood.
- 01
Problem and system boundary analysis
We clarify users, data, integrations, current constraints and the outcome that should be visible after delivery.
- 02
Contracts and data model
I design the API, data structures, authorization and system behavior for invalid or incomplete scenarios.
- 03
Implementation and integrations
I build the service in testable stages and make the key flows available in a development or staging environment.
- 04
Documentation and deployment
I prepare configuration, containers, API documentation and the information required for continued development or handoff.
Backend stack and tools
Kotlin is my primary backend language, and I use Go for lightweight services and data integrations.
Backend
- Kotlin
- Spring Boot
- Ktor
- Spring Data JPA
- Hibernate
- Go
Data and security
- PostgreSQL
- Redis
- Spring Security
API and quality
- REST API
- OpenAPI
- JUnit
Deployment
- Docker
- Linux
- CI/CD
Related project
LibrePass
LibrePass demonstrates a Kotlin and Spring Boot backend, authentication, REST APIs, encrypted data and synchronization between client and server.
Related services
Need a backend or integration?
Describe the product, existing system and the most important problem. I will help define a practical first stage.
Contact me