Junior/Mid FullStack Developer with Blockchain

Rumblefish; Kraków; On-site; PLN 40,000 - 60,000; Full time

Benefits offered by this job

Paid holidays

Training budget

Private healthcare

Non-corporate culture

Flexible hours

Multisport Plus or gym pass

Supportive team

Job summary

A software development company in Poland is looking for a Junior/Mid FullStack Developer with Blockchain experience. The ideal candidate will build modern web applications using technologies like React, Node.js, and AWS, and work on exciting blockchain projects. Excellent communication skills and a willingness to learn new technologies are essential. The position offers a hybrid work model with various benefits including paid holidays, a training budget, and private healthcare.

Qualifications

• Basic understanding of frontend/backend structure and AWS services exposure.
• Familiarity with React and TypeScript.
• Basic knowledge of Rust and willingness to learn.
• Comfortable working with APIs (REST, GraphQL).
• Basic blockchain concepts and interest in applied cryptography.
• Excellent communication skills and openness to new tools.

Responsibilities

• Build and develop full-stack applications (React, Rust, AWS).
• Work on real blockchain/Web3 projects.
• Integrate frontend and backend with blockchain data.
• Design and implement APIs for indexing and data processing logic.
• Work closely with a product team and communicate in English daily.

Skills

React

TypeScript

Node.js

NestJS

Material UI

REST

Docker

AWS

Rust

Stellar Blockchain

Postgres

Job description

Join our team as Junior/Mid FullStack Developer with Blockchain in Krakó | Hybrid. We’re looking for a Junior/Mid-level FullStack Blockchain Developer passionate about building modern web applications and curious about blockchain systems. Help us develop tools that make interacting with on‑chain data and smart contracts more accessible and transparent.

Qualifications

• Basic tech stack: React, TypeScript, Node.js, NestJS, Material UI, REST, Docker, AWS.
• Nice to have: Rust, Stellar Blockchain, Postgres.
• Important traits: Basic understanding of frontend/backend structure and AWS services exposure; familiarity with React and TypeScript; basic knowledge of Rust and willingness to learn; comfortable working with APIs (REST, GraphQL); basic blockchain concepts and interest in applied cryptography; comfortable using AI coding tools; excellent communication skills, team spirit; openness to new tools; understanding when not to fully rely on AI; proficiency in spoken English.

Responsibilities

• Build and develop full‑stack applications (React, Rust, AWS).
• Work on real blockchain/Web3 projects.
• Integrate frontend and backend with blockchain data.
• Design and implement APIs for indexing and data processing logic.
• Work closely with a product team and communicate in English daily.

Benefits

• Paid holidays
• Training budget
• Private healthcare
• Non‑corporate culture
• Hybrid work environment with flexible hours
• Multisport Plus or gym and swimming pool pass for a nearby facility
• Supportive team that loves sharing knowledge

About the project

You may join one of our blockchain projects, such as building tools around the Stellar / Soroban ecosystem, including a smart contract block explorer. Your work will focus on making on‑chain data more accessible and understandable – helping developers and users explore transactions, contracts, and blockchain activity in a clear and meaningful way.

We don’t expect you to have experience with these particular technologies, as these are quite niche. What we do expect is that you’re eager to learn and explore.

At Rumble Fish, we work on a variety of projects across blockchain, cloud, and AI, so depending on the project you may also have the opportunity to explore different technologies and domains over time.

If you’re excited about building real products, working with modern technologies, and growing your skills in the Web3 space – let’s talk!