O Oskar Karpiński

Backend, APIs and integrations

Backend systems, REST APIs and integrations

I design backend systems, REST APIs and integrations primarily with Kotlin, Spring Boot and Ktor, with Go, PostgreSQL and Docker where appropriate.

What I can deliver

I design and build backend systems matched to the product, team and maintenance needs.

Example use cases

  • A new product backend
  • REST API for a web or Android application
  • Integrations with external services
  • Data synchronization and webhooks

Technologies

  • Kotlin
  • Spring Boot
  • Spring Security
  • Spring Data JPA
  • Hibernate
  • Ktor
  • REST API
  • JWT
  • OpenAPI
  • JUnit
  • integration testing
  • Go
  • Docker

Delivery process

  1. 01

    Understand the domain, users and system boundaries

  2. 02

    Design API contracts, data models and authorization

  3. 03

    Implement integrations, scheduled tasks and synchronization

  4. 04

    Test, document the API, containerize and prepare deployment

Related public project

LibrePass

A public archived reference project showing Kotlin/Spring Boot backend systems, REST APIs, authorization and synchronization.

LibrePass

Related services

Need a backend or integration?

Describe the scope and I will help define a practical next step.

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