Backend 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

Senior Software Engineer

Responsibilities:

• Lead by the principle of "customer first" to analyse, debug, develop, and maintain customer-centric software.

• Collaborate closely with multidisciplinary teams to analyse, debug and fix issues with high quality code, zero regressions, scalable, innovative technical solutions.

• Optimizing components for maximum performance and scalability

• Participates in R&D, Proof of Concepts, Prototyping, Code review, Root Causing, etc.

• At least 2-3 yrs of experience in taking full ownership of software development lifecycle including planning, design, architecture, development, test & deployment. And 2+ years of experience in supporting production or customer issues and escalations.

• Review and analyze support tickets that are complex in nature and require more technical knowledge to analyze. Investigate issues to identify root causes and document findings clearly.

• Influences the development practices so that they follow best practices, policies, and procedures.

• Ensure software products meet all non-functional requirements including operational and security needs.

• Excellent verbal and written communication skills, problem solving skills.

• Address complex technical challenges within software systems, ensuring robustness, compliance, and customer satisfaction.

• Contribute to knowledge base

• Support the Lead and Mentor the team of software engineers and own the technical health of the service the team is working on.

Requirements:

• Bachelor’s or Master’s degree in Computer Science, Engineering, or a related field.

• Minimum of 5 years of professional experience in Java development with expertise in core Java, JDK, data structures, and multithreading.

• Strong analytical skills with experience in root cause analysis and fixes • Strong experience with Spring and Spring Boot frameworks.

• Strong understanding of software design principles, architecture, and best practices

• Familiarity with server technologies, including Tomcat and WebLogic.

• Proficiency in working with relational databases such as Oracle and PostgreSQL

• Experience with messaging queues, particularly JMS MQ or Artemis MQ.

• Possess exceptional debugging and troubleshooting skills to resolve complex issues across the entire, cross-functional technology stack

• Awareness / exposure to debugging Frontend applications (ReactJS / .Net) is a good to have.

• Exposure to Kubernetes, containerization and cloud (AWS) technologies in building scalable, resilient, and distributed environments.

• Excellent problem-solving skills and the ability to work in a fast-paced and in production customer sensitive environments.

• Strong communication and collaboration skills. Quick learner.

• Experience and knowledge in working in the HRP application – specifically the Claims functionality. Added experience in other areas including Enrollment, Billing, Financials is a plus. Candidate must have worked previously in HRP

• Familiarity with ticketing systems (Jira, SalesForce) and production support workflows.

• Design and develop innovative, company impacting products and services to support infrastructure operations
• Design, develop and implement object-oriented PHP applications from prototype through implementation
• Integrate open source and commercial enterprise applications into an exposed API and web-based portal
• Create highly scalable and performant REST/SOAP web services
• Keep focus on end users and goals all through the development process
• Work closely with product management and stakeholders to ensure applications meet needs and expectations
• Adhere to the highest levels of technical discipline and excellence to set a standard for the larger development organization

Requirements

• Bachelor's Degree in Computer Science, related field, or comparable extra work experience
• Solid experience with SQL and relation databases
• Solid experience with Object Oriented Design and Development
• Experience Developing API Interfaces
• Experience with version control systems, preferably Git

Beneficial Skills

• Experience with non-relational data stores such as ZooKeeper or Memcache

7+ years of experience with Design, development & architecture.

• Experience in software development with minimum 3 plus years of architecture experience.
• Experience in Core JAVA 8
• Experience in Java J2EE, Microservices
• Experience in Java - Spring, Java - SpringBoot, GCP , Hibernate,JDBC
• Experience in Multi-threading, Performance and Scaling is a plus
• Have used the RDBMS and NoSQL databases like MySQL/Oracle, MongoDB, Cassandra, Neo4J Risk for production ready software’s
• Cloud Native application design experience is a plus
• CICD – Release Pipeline experience
• Experience in application of principles of Architecture Design
• Experience building large scale, high performance distributed systems
• Strong understanding of modern development techniques and processes such as Dev Ops /Cloud
• Promoter of Agile/Scrum, TDD and CI/CD best practices
• Analyzes, designs, programs, debugs and modifies software enhancements and/or new products used in local, networked or Internet-related computer programs. (Code must be used in core version of applications available for sale commercially.)
• Interacts with Delivery managers and/or users to define system requirements and/or necessary modifications.
• Participates in software design meetings and analyzes user needs to determine technical requirements.
• Write technical specifications based on conceptual design and stated business requirements.
• Writes code, completes programming and performs testing and debugging of applications using current programming languages and technologies.
• Completes documentation and procedures for installation and maintenance.
• Trains and communicates with internal Client Training, Client Relationship and Sales teams on systems application.
• May be responsible for developing or executing project plans, budgets and schedules and for documenting work and results.
• May deliver informational and decision-seeking presentations to technical and business groups to internal and/or external audiences.

Roles & Responsibilities:

Build efficient, testable, and reusable PHP modules.

Solve complex performance problems and architectural challenges.

Integration of data storage solutions (may include databases, key-value stores, etc.).

Integration of User Interfaces developed by front end developers.

Skills and Qualifications:

· Must have a bachelor’s degree or above in Computer Science or in similar field.

· Minimum 4 years of experience in PHP web development.

· Strong knowledge of front-end technologies, such as JavaScript, HTML5, and CSS3

· Strong knowledge of PHP web frameworks (CodeIgniter, NodeJS)

· Experience in creating custom modules and themes.

· Expert knowledge in web architecture.

· Strong understanding of MVC design patterns and oops concept.

· Strong understanding of full synchronous behaviour of PHP.

· Experience with modern UI frameworks such as React, Angular or Vue.js

· Experience in MySQL and the ability to write SQL queries.

· Proficient understanding of source control management such as Git, SVN.

· Proficient understanding fundamental design principles behind a scalable application.

· Familiarity with limitations of PHP as a platform and its workarounds.

· Ability to create database schemes that represent and support business processes.

· Experience with Edu Tech companies will be preferred.

. Immediate Joiner Preferred.

Mandatory Skills:

1. Good Coding Skills
2. Hands on Experience on C#
3. Indexer
4. Object Oriented concepts using C#
5. Linq
6. Generics
7. Delegates
8. File IO
9. GAC concepts
10. MVC
11. Entity framework
12. .Net Core Concepts
13. Web-API
14. Sql Queries

Secondary Skills:

• Knowledge of Angular/React/Vue/Java Script/ Type Script
• Knowledge of HTML and CSS
• SQL Server and PL/SQL
• Understanding of Design Patterns

Interpersonal Skills:

1. Good in communications (Verbal and Written)
2. Should have worked individually or in team

Job Description:

• Team with top-notch engineers, product managers, program managers, DevOps and QA following agile development methodologies
• Review functional requirements, providing technical feedback on feasibility and architectural approach and framework.
• Design and develop web / mobile applications
• Create Prototype and/or Proof of Concepts (POCs) when necessary
• Act in a technical leadership capacity: Mentor junior engineers and new team members, perform code reviews and apply technical expertise to challenging programming and design problems
• Utilize Agile Development, SCRUM / Pair / Extreme Programming methodologies
• Design and develop supporting components and microservices for the backend tiers focusing on fault-tolerance and scalability in a multi-tenant enterprise environment
• Maintain and improve the functionality and performance of the existing web applications
• Help shape and execute the technical roadmap to develop next generation features; integrate corporate- and product-level architecture principles and goals into the teams project work through designs, implementation strategies, and project planning.
• Drive a culture of quality, technical curiosity, continuous improvement, and evidence-based data driven decision making in the organization.
• Execute other Duties as assigned

• 3+ years of experience developing Backend, API and data-based applications/software
• Experience with one of the major relational databases (MySQL, Oracle, Postgres) and NoSQL databases (Mongo DB, Cassandra, Dynamo DB or such)
• Expert object-oriented programming experience using Java
• Strong OO design and programming skills in Java, Hibernate, JPA, Spring Boot
• Worked in Maven, JPA, REST services, Postman
• Working knowledge on Spring Security / Spring Batch / ZUUL / Eureka / Hysterix
• Exposure with Frontend technologies (React.js, Angular or Ruby-on-Rails)
• Require experience and Strong understanding of entire Software Development Life Cycle (SDLC), Agile (Scrum), Software design/architecture process, unit testing & Test-Driven Development (TDD)
• Experience with web services (consuming or creating)
• Experience managing Cloud infrastructure (resources and service) in AWS, Azure and/or GCP
• Strong knowledge of SOA, object-oriented programming, design patterns, multi-threaded application development
• Experience in reporting and analytics, queuing and real-time streaming systems
• Git or similar distributed SCM tools experience.