Blockchain Developer

We are looking for a Blockchain Developer to join a long-term project focused on institutional digital asset and Bitcoin wallet infrastructure.
The role is focused on building and supporting secure Bitcoin-related solutions, including transaction processing, UTXO management, multisig and wallet infrastructure.

Requirements
3+ years of production experience in blockchain development, with strong hands-on experience with Bitcoin
Strong understanding of the Bitcoin network and transaction lifecycle
Experience with UTXO management and manual transaction construction
Strong knowledge of PSBT, SegWit, Bitcoin Script and address types
Experience with multisig wallets
Understanding of fee estimation, RBF and CPFP
Experience with Bitcoin wallet or custody infrastructure
Strong Java, Spring Boot and SQL
Familiarity with TDD and/or BDD
Understanding of Domain-Driven Design principles
Experience working with monorepos and CI/CD pipelines
Good communication skills and ability to work in a cross-functional team
English — B2 or higher

Responsibilities
Develop and maintain Bitcoin wallet infrastructure
Work with UTXO management and transaction construction
Implement and support PSBT, SegWit and multisig workflows
Work with transaction fees, RBF and CPFP
Contribute to backend architecture and integrations with Bitcoin nodes
Monitor and troubleshoot production issues
Participate in technical design and development of new features
Collaborate with other engineers across the project

What we offer
Full-time, remote position
Long-term cooperation
Flexible location within the EU, with a particular focus on Ukraine and the Balkans
Opportunity to work on institutional-grade blockchain infrastructure
Start: ASAP