SENIOR BLOCKCHAIN ENGINEER, MADRID

Senior Blockchain Engineer
Join Tether and Shape the Future of Digital Finance

At Tether we re not just building products we re pioneering a global financial revolution. Our cutting-edge solutions empower businesses from exchanges and wallets to payment processors and ATMs to seamlessly integrate reserve-backed tokens across blockchains. By harnessing the power of blockchain technology Tether enables you to store send and receive digital tokens instantly securely and globally all at a fraction of the cost. Transparency is the bedrock of everything we do ensuring trust in every transaction.
Innovate with Tether

Tether Finance Our innovative product suite features the world s most trusted stablecoin USDT relied upon by hundreds of millions worldwide alongside pioneering digital asset tokenization services.

But that s just the beginning
Tether Power Driving sustainable growth our energy solutions optimize excess power for Bitcoin mining using eco-friendly practices in state-of-the-art geo-diverse facilities.

Tether Data Fueling breakthroughs in AI and peer-to-peer technology we reduce infrastructure costs and enhance global communications with cutting-edge solutions like KEET our flagship app that redefines secure and private data sharing.

Tether Education Democratizing access to top-tier digital learning we empower individuals to thrive in the digital and gig economies driving global growth and opportunity.

Tether Evolution At the intersection of technology and human potential we are pushing the boundaries of what is possible crafting a future where innovation and human capabilities merge in powerful unprecedented ways.
Why Join Us?

Our team is a global talent powerhouse working remotely from every corner of the world. If you re passionate about making a mark in the fintech space this is your opportunity to collaborate with some of the brightest minds pushing boundaries and setting new standards. We ve grown fast stayed lean and secured our place as a leader in the industry.

If you have excellent English communication skills and are ready to contribute to the most innovative platform on the planet Tether is the place for you.

Are you ready to be part of the future?
Tasks
The Senior Blockchain Engineer will work on a wallet development kit an open source tool for integrating various cryptocurrency primitives like payments smart contract applications L2 into various projects like payments app AI agent integrations.
Key Responsibilities

- Design and implement modular non-custodial wallet libraries with support for multiple cryptocurrencies for mobile web and server using Javascript.

- Develop and integrate wallet modules for various blockchain protocols with focus on security and key management.

- Create reliable payment processing systems that interface directly with blockchain nodes.


Requirements

- Strong experience building non-custodial cryptocurrency wallets and key management systems

- Deep understanding of blockchain principles like the UTXO model.

- Hands-on experience running and maintaining blockchain nodes (Bitcoin Ethereum etc.)

- Deep understanding of P2P networking concepts and distributed systems

- Strong focus on security best practices and cryptographic principles

- Advanced JavaScript/Node.js expertise including

- Modern ES6+ features and async programming

- Buffer handling and cryptographic primitives

- WebSocket/REST/RPC API interactions

- Test-driven development practices

- Understanding of Node.js runtime architecture.


Nice to have

- Experience with hardware wallet integration

- Familiarity with P2P technologies like Bitorrent/DHT/Holepunch

- Knowledge of BIP standards (BIP32 BIP39 BIP44 etc.)

- Familiarity with Layer 2 token DeFi protocols

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