RoofStacks Jobs

Senior Backend Developer (Card Payment Systems)

RoofStacks

Senior Backend Developer (Card Payment Systems)

Reposted 21 Days Ago

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Hiring Remotely in İstanbul, Şişli, İstanbul, TUR

Remote or Hybrid

Senior level

Software

The Role

The Senior Backend Developer will work on card payment systems, enhancing the platform for debit, credit, prepaid cards, and handling integrations, transaction management, and secure payment scheme interactions.

Summary Generated by Built In

At Roofstacks, we’re building innovative financial technologies that power seamless card experiences. We are now looking for a Senior .NET Developer to join our growing Card Payment Systems team. If you're passionate about banking, payments, and high-performance backend development—this opportunity is for you.

🧩 What You’ll Be Doing

You will take part in the full development lifecycle of our card platform, working on mission-critical services used in:

- Card application flows for Debit, Credit, Prepaid, Digital & Commercial cards

- Integrations with KKB/LKS, Decision Support, Analytics Solutions and onboarding systems

- Development of card lifecycle and transaction management services (issuance, renewal, limits, fraud, posting, fee, campaign, extre, DWH etc.)

- Secure integrations with payment schemes (Visa, Mastercard, BKM, CUP, Discover) and EMV scripting/PIN management

- POS ecosystem integrations (TechPOS, Ingenico SDK, CAT transaction flows, parameter distributions)

- Real-time and batch transaction processing with high availability (99.9% uptime) requirements

- Working with ISO 8583 messaging, socket programming, TCP/IP protocols

- Supporting authentication flows via OAuth2, OpenID Connect, JWT/JWS, and 3DS SDK/ACS

✅ What We’re Looking For

- Minimum 5+ years of experience in software development

- Bachelor’s degree in Computer Engineering, Software Engineering, or related field

- Strong experience in C#, .NET Core / .NET Framework

- Solid command of SQL / PL-SQL (Oracle preferred)

- Experience in multi-threaded applications and performance optimization

- Prior banking or fintech experience is highly preferred

- Hands-on with RESTful API, Webhook integrations

- Strong debugging, testing, and system integration skills

- Good command of English is a plus

⚙️ Nice-to-Have Experience

- Experience with other OOP programming languages (such as Java, Python, Kotlin, etc.)

- EMV transaction flow, 3DS 2.x, ACS and GO integration

- Encoding/decoding logic in card-based data formats

- High-performance architecture experience in financial transactions

- Familiarity with scheme compliance (Visa/Mastercard bulletins & updates)

- Experience in distributed system development

- Familiarity with TCP/IP Socket programming, encoding/decoding formats (hex, bcd, ebcdic)

- Understanding of HSM, key management, encryption flows is a plus

Skills Required

5+ years of experience in software development
Bachelor's degree in Computer Engineering, Software Engineering, or related field
Strong experience in C#, .NET Core / .NET Framework
Solid command of SQL / PL-SQL (Oracle preferred)
Experience in multi-threaded applications and performance optimization

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The Company

Austin, , Texas

322 Employees

What We Do

ABOUT US Roof Stacks Inc. is an innovative and a complete domestic software company who brings new technologies to Turkey since its foundation in 2015. Roof Stacks Inc, strengthens its place in the developing technology and rapidly growing market with specializing in tourism systems, augmented reality and e-commerce. Head office is in Gebze Bilişim valley and its branches are in Elazig and Antalya. Therewithal a new branch Office opened in 2020 in Austin, USA. Canada and Netherlands offices also will serve soon. Roof Stacks Inc, provides speed, efficiency and cost reduction benefits to its partners while strengthening business partners’ competitive positions with the innovative technology produced. UNITS Roof Travel Roof Stacks is the software developer of Bilet Dükkanı, the leading online ticket sales portal of Turkey which simplifies travel agencies' work flow. Bilet Dükkanı offers innovation on all travel and tourism related ticket sales transactions such as flight tickets, hotel reservations and insurance operations. Roof Money GoArt, which is a Roof Stacks project and introduces historical places with augmented reality technology, is the first in the world. Coins that can be collected while browsing the virtual cities of GoArt, makes Roof Stacks a different company that also develops its own payment methods. This coin technology called “Goarc” is operated based on Ethereum. Roof Games Roof Stacks, an ambitious actor, rapidly growing in the digital gaming market. The global gaming market has a volume of $ 180 billion annually. Roof Stacks comes in as one of the top exporters in Turkey with its innovative inputs in game development industry