Senior Blockchain Engineer (100% remote - Spain)

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.

About the job :

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.

Minimum 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.

This role focuses on building a non-custodial wallet library using Javascript, while maintaining high security standards. The ideal candidate should be passionate about cryptocurrency technology and have a proven track record of developing secure, user-focused wallet solutions.

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