Java Jobs in Web3

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Job Position Company Posted Location Salary Tags

RoofStacks

İstanbul

$106k - $114k

Okx

Remote

$143k - $257k

Launchpadtechnologiesinc

Remote

$75k - $105k

Bitmex

Remote

$120k - $148k

Tastylive

Remote

$124k - $145k

Okx

Remote

$143k - $257k

Zscaler

Remote

$98k - $100k

Zinnia

Remote

$98k - $120k

Kraken

European Union

$106k - $114k

Dune

London, United Kingdom

$36k - $54k

Copperco

Remote

$112k - $156k

Binance

Taipei, Taiwan

Crypto.com

Bangalore, India

$126k - $131k

Zscaler

Remote

$84k - $107k

Public

New York, NY, United States

$81k - $84k

RoofStacks
$106k - $114k estimated
İstanbul
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Senior Backend Developer (Card Payment Systems)

İstanbul
RoofMoney – Kart Paketi /
Full Time /
Hybrid

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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

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What does a Java developer in web3 do?

A Java developer in web3 would likely be focused on developing applications that use the Java programming language in the context of the web3 technology stack

Web3 is a collective term used to refer to the next generation of decentralized, blockchain-based technologies that are aimed at creating a more open and secure internet

In this context, a Java developer would be responsible for writing code that interacts with web3 technologies, such as decentralized applications (DApps) and smart contracts, to create new tools and services that run on the blockchain

This could involve working with cutting-edge technologies such as Ethereum, which is a popular blockchain platform that uses the Java programming language, as well as other web3 technologies and frameworks.