ROR Developer

About ZYSYGY

ZYSYGY is building Germany's zero-fee payment network. Merchants pay zero transaction fees. We route payments directly over SEPA Instant, bypassing Visa, Mastercard, and the entire card network chain. No hardware. No card reader. Just a phone.

We are building the first company to combine a fully software-based merchant POS with a consumer super-app for everyday financial life: payments, transport, utilities, government services, all in one place. Think what UPI did for India. We are doing it for Germany, from the ground up, on banking rails.

Role Overview

You will join the core engineering team as a founding engineer. You will own the backend payment engine end to end: transaction flows, wallet management, SEPA Instant settlement, KYB/KYC integration, recurring mandates, refund logic, and the compliance export layer (DATEV, Kassenbuch, GoBD, fiskaltrust). On mobile, you will contribute to the React Native consumer and merchant apps alongside our mobile engineer.

You will own what you build from development through deployment, monitoring, and production reliability. The architecture decisions you make in the first six months will run in production for years.

What you will do

Design and build the backend payment engine: transaction flows, wallet management, SEPA Instant settlement, offline payment authorization, and recurring mandate billing.

Own KYB/KYC integration and the compliance export layer: DATEV, Kassenbuch, GoBD, and fiskaltrust for KassenSichV.

Build REST APIs for financial-grade reliability and high-throughput transaction processing, including full R-transaction handling and reconciliation pipelines.

Contribute to the React Native consumer and merchant mobile apps alongside our mobile engineer.

Own the full lifecycle of what you build, from development through deployment, monitoring, and continuous improvement.

Integrate AI tooling into your development workflow as a matter of course: code generation, automated testing, and intelligent review.

Who you are

Meaningful hands-on experience building payment systems, fintech infrastructure, or financial APIs.

You have designed a ledger. You understand double-entry bookkeeping, immutable transaction records, and why you never update a financial row.

You have solved the partial failure. Money left one wallet and did not arrive in the other. You know how to detect it, resolve it, and make sure it does not happen again.

You understand idempotency at a design level. You have built systems that survive client retries, duplicate webhooks, and network drops without double-charging anyone.

You have built or reasoned about reconciliation: detecting discrepancies between your internal ledger and an external settlement file, and resolving them reliably at scale.

You understand KYC and KYB state machines, what happens when verification status changes mid-transaction, and what a regulator expects from your audit trail.

You are comfortable with SQL databases and own the full lifecycle of your code from development through deployment.

You can communicate technical decisions clearly to non-technical stakeholders. At this stage of the company, that matters.

You are a continuous learner. Payments infrastructure is a deep domain and you treat it that way.

You are comfortable with ambiguity and early-stage risk. There is no playbook yet. You will help write it.

Strong academic background preferred. Demonstrated engineering ability matters more than institution.

Relocation

Relocation to Munich, Germany, is on the table for the right candidate, including visa support.

Connect with the Founder

You can also connect with me on LinkedIn at www.linkedin.com/in/shabbir-maimoon

Description

Join company as a Backend Developer and become a pivotal force in building the robust, scalable services that power our innovative platforms. In this role, you will design, develop, and maintain server‑side applications, ensuring high performance and reliability for millions of users. You’ll collaborate closely with cross‑functional product, front‑end, and DevOps teams to translate business requirements into clean, efficient code, while participating in code reviews and architectural discussions. Our dynamic environment encourages continuous learning, offering opportunities to work with cutting‑edge technologies, cloud infrastructures, and modern development practices. As a key contributor, your work will directly impact product quality, user satisfaction, and the overall success of company's mission to streamline hiring solutions.

Requirements:

• 1–15 years of professional experience in backend development, with a strong focus on building APIs and microservices.
• Proficiency in server‑side languages such as Python, Java, Node.js, or Go, and solid understanding of object‑oriented and functional programming paradigms.
• Extensive experience with relational (e.g., PostgreSQL, MySQL) and NoSQL databases (e.g., MongoDB, Redis), including schema design and query optimization.
• Familiarity with cloud platforms (AWS, GCP, Azure) and containerization technologies like Docker and Kubernetes.
• Hands‑on experience with version control (Git), CI/CD pipelines, and automated testing frameworks.
• Strong problem‑solving abilities, effective communication skills, and a collaborative mindset for working within multidisciplinary teams.

Roles and Responsibilities:

• Design, develop, and maintain high‑throughput backend services and RESTful APIs that support core product features.
• Implement data models and storage solutions, ensuring data integrity, security, and optimal performance.
• Collaborate with front‑end engineers, product managers, and designers to define technical requirements and deliver end‑to‑end solutions.
• Participate in code reviews, provide constructive feedback, and uphold coding standards and best practices.
• Monitor, troubleshoot, and optimize production systems, implementing robust logging, alerting, and performance tuning.
• Contribute to the continuous improvement of development workflows, including CI/CD automation, testing strategies, and deployment processes.
• Stay current with emerging technologies and industry trends, proposing innovative approaches to enhance system architecture.

Budget:

• Job Type: payroll
• Experience Range: 1–15 years

• Implement best practices for the engineering team across code hygiene, overall architecture design, testing, and deployment activities
• Drive technical decisions for building data pipelines, data lakes, and analyst access.
• Act as a leader within the engineering team, providing support and mentorship for teammates across functions
• Bachelor’s Degree in Computer Science or equivalent job experience
• Experienced developer in large data environments
• Experience using Git productively in a team environment
• Experience with Docker
• Experience with Amazon Web Services
• Ability to sit with business or technical SMEs to listen, learn and propose technical solutions to business problems

·       Experience using and adapting to new technologies

·       Take and understand business requirements and goals

·       Work collaboratively with project managers and stakeholders to make sure that all aspects of the project are delivered as planned

·       Strong SQL skills with MySQL or PostgreSQL

• Experience with non-relational databases and their role in web architectures desired

 Knowledge and Experience:

• Good experience with Elixir and functional programming a plus

• Several years of python experience
• Excellent analytical and problem-solving skills
• Excellent organizational skills

Proven verbal and written cross-department and customer communication skills

• JAVA Microservices with AWS needed
• Provide solution architecture & design involving Cloud and DevOps
• Develop new microservices in a cloud-native way.
• Ensure the unit testing and code coverage are achieved as per the agreed percentage.
• Build reusable code and libraries for future use.
• Optimize application for maximum performance and scalability.
• Collaborate, and coordinate with team members and key stakeholders.
• Communicate effectively with different stakeholders.
• Ensure best practices & standards are followed during SDLC.
• Takes ownership of the whole solution from a technical perspective and ensures adherence to defined Architecture & Design.
• Ensures the latest technology standards, and guidelines are utilized for development.
• Performs consistent & adequate code reviews & feedback to the team.
• Training and induction of new resources on the projects.

Skills and Qualifications

• Deep understanding of OOPs and OOAD.
• Expert and hands-on in Java JEE and Spring framework, Spring Boot.
• Should have experience with RESTful web services and API standards.
• Should know various integration patterns in distributed environments.
• Working knowledge of microservice architecture and different design patterns.
• Hands-on in writing unit tests with Mockito and code coverage tools.
• Hands-on data modeling (Logical physical).
• Knowledge of RDBMS, SQL and any ORM framework (JPA, Hibernate etc.)
• Should know Event-driven and asynchronous programming using message broker.
• Should know about cloud IaaS, PaaS, SaaS and Serverless models of any cloud provider (AWS, Azure, GCP), preferably AWS.
• Knowledge of JavaScript frameworks like NodeJS (For the Backend) and Angular React (For Frontend) will be added advantage.
• Good to have DevOps related technologies like Container (Docker), Container Orchestrator (Kubernetes EKS)
• Excellent in communication

As a Senior Software Engineer you have complete ownership of building out the Docexa product along with product people and the rest of the engineering team. This role will act as a great springboard to accelerate career growth & transition into a Tech Lead level role.

Your daily life

• Architecting of the whole platform
• Development of server-side logic
• Building new services and APIs
• Developing core business logic
• Maintenance of current APIs
• Improving the performance and reliability of our systems as we scale

Must-have skills

• You’ve been building web applications professionally for 4+ years
• You’re proficient in PHP 7, Laravel, and PostgreSQL
• You possess strong OOP and design pattern knowledge
• You are familiar with modern technology systems: AWS, load balancers, Kafka queues, caching, etc.
• You write understandable, testable and easy to maintain code
• You’ve the ability to build RESTful APIs
• Explaining complex technical concepts to designers, support team, and fellow engineers is not a problem for you
• Well versed with the fundamentals of computer science and distributed systems

We are looking for a Node.js Developer who is proficient with writing API's, working with data, using AWS and capable of applying algorithms mainly machine learning-based to solve problems and create/modify features for our students. Your primary focus will be the development of all server-side logic, definition and maintenance of the central database, and ensuring high performance and responsiveness to requests from the front-end. You will also be responsible for integrating the front-end elements built by your co-workers into the application. Therefore, a basic understanding of front-end technologies is necessary as well.

Responsibilities

• Integration of user-facing elements developed by front-end developers with server-side logic
• Writing reusable, testable, and efficient code
• Design and implementation of low-latency, high-availability, and performant applications
• Implementation of security and data protection
• Use of algorithms to drive data analytics and features.
• Ability to use AWS to solve scale issues.