Freelance projects

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Search for a Backend Developer (Kotlin + Spring Boot) for a large-scale mobile service Smart Mobility

Java — incorrectly specified categories?

300 USD

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We are looking for an experienced Backend Developer for long-term work on a large commercial project Smart Mobility — a full-fledged real-time ride-hailing service (like Uber/Bolt/BlaBlaCar), but with enhanced social interaction and unique POOL trip algorithms.

❗ IMPORTANT

The current project is not suitable for PHP. We need a specialist who:

is proficient in Kotlin + Spring Boot 3,
understands multithreading, low-latency, WebSockets, real-time logic,
has experience building high-load APIs,
works with geolocation, event queues, Redis/Kafka,
can design scalable architecture.

📌 Stack (mandatory)

Kotlin
Spring Boot 3
WebFlux (reactive stack)
PostgreSQL
Redis
WebSocket
Docker
Advantage: Kafka, Firebase, Mapbox/OSRM routing API

📌 Brief about the project

Smart Mobility is a service that includes:

individual and shared POOL trips;
POOL algorithm
real-time passenger matching;
group rooms (Rooms) with chat;
private chat “Nearby” between passengers;
Secure Ride (live tracking for trusted persons);
No-Show logic, referral scenarios, social statuses, ratings;
separate functionality for drivers (cooperative).

There is a lot of work to do. This is not a “simple taxi”.

We need a specialist who understands complex systems and is ready to participate in the development of the complete backend core.

📌 Requirements

3+ years of commercial development on JVM (Kotlin or Java).
Experience with microservices, real high-load APIs.
Understanding of concurrency, race conditions, fault tolerance.
Ability to design data models and complex business logic.

📌 Tasks for the near future (MVP Backend)

Authorization/roles (passenger/driver)
Trips & POOL Engine (Base, Extra, Required Payout)
Matching
FSM states of the trip
Rooms + WebSocket Chat
Secure Ride (live tracking)
Implementation of tariffs (SOLO/POOL)
Logging of critical events

📌 What we offer

complete technical specifications, including formulas, logic, scenarios;
access to all UI mockups and requirements;
technical support and product maintenance;
adequate budget if the level matches.

If you are a specialist in Kotlin/Spring Boot and love complex tasks — we look forward to your response.
Further – payment step by step, for each module separately.

Proposals 7

Andrіy Sokіl

0 0

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Budget: 300 USD Deadline: 7 days

I am looking for a long-term project with 20 years of experience. Spring Boot 3, Redis/Kafka, Postgres, etc. The rate is formal, I am ready to discuss the details.

Anastasiia Sherkunova

0 0

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Rating 164

Budget: 300 USD Deadline: 5 days

Hello! 👋 You are greeted by Anastasia, the 256Devs team. We provide services of qualified Backend developers who specialize in Kotlin and Spring Boot for creating high-performance and reliable enterprise solutions. We guarantee clean architecture, adherence to deadlines, and effective integration into your current or new project. Please send a description of the tasks or project for scope assessment.

Food delivery system for a restaurant chain

Alexey Manuilskyi

0 0

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Rating 472

Budget: 300 USD Deadline: 5 days

Здравствуйте!
Меня зовут Алексей, я представляю группу разработчиков – NC-1.
В нашей команде есть специалист (mobile-developer, senior) с необходимыми для Вас опытом и знаниями. Ставка в час - 26 usd.
Стек: Java, Kotlin and Dart.Git, GitFlow, Github and Bitbucket. Room, Active Android,GreenDao. Kotlin Coroutines and RxJava2. XML and JSON.Postman, SoapUI & Figma. Simple XML Parser, GSON, Moshi and Retrofit 2. HTTP Url Connection, Asynchronous HTTP Client, OkHttp2.CHUCK.Lint, KtLint. MVP, MVVM and MVVM + clean architecture. Dagger Hilt, Dagger2 and Koin. Jira, Trello. SOLID, Dry. XML & Jetpack Compose.CameraX (ImageCapture and VideoCapture). Espresso, UI Automator. JUnit 4, Truth, Mockito and Mokk. Google play console, Firebase app distribution and Fastlane.SwiftUI, SwiftData, R.Swift. AppWrite
Кейсы: https://1drv.ms/b/c/b7a0d31a9dae1bc5/IQCpK38gmEvWT6F_Cso40Li-AXAKkSs-J67mCwll-C732pw?e=v4VVF5
С уважением,
Алексей М.

David Lb

0 0

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Rating 348

Budget: 300 USD Deadline: 3 days

Hello! With extensive experience in Kotlin/Spring Boot and reactive systems, I am ready to develop the backend core of Smart Mobility, handling POOL trips, real-time matching, chat, and secure trip tracking. My approach ensures clean architecture, concurrency safety, and step-by-step delivery of modules according to your technical requirements. Thank you.

Giorgi Zenaishvili

5 1

Budget: 300 USD Deadline: 2 days

Hello! I have reviewed your assignment and believe that I can successfully complete it. I would be happy to collaborate, please write to me personally for further details.

The list does not show proposals concealed by the client or freelancer with a Plus profile, as well as proposals violating rules

Yurii Potsiluiev
Oslo, Norway

Projects 3
Rating 5.0
Rating 261