We are looking for an experienced Senior Blockchain Developer with strong hands-on expertise in Bitcoin (BTC) and Java to join a long-term project focused on production-grade Bitcoin wallet and custody infrastructure.

Location: EU-based candidates
Working model: Fully Remote
Workload: Full-time
Start: ASAP
Duration: Long-term
English: B2 or higher

Must-have experience:

• Strong Java development experience, including Spring Boot and SQL
• 3+ years of production blockchain experience with Bitcoin (BTC)
• Deep understanding of how the Bitcoin network and transactions work
• Hands-on experience with manual Bitcoin transaction construction and UTXO management
• Strong knowledge of SegWit, address management, Bitcoin Script and address types
• Experience with PSBT and transaction construction
• Strong understanding of the Bitcoin transaction lifecycle
• Experience with fee estimation and management, RBF and CPFP
• Strong knowledge of secure wallet key management
• Strong experience with multisig / multi-signature coordination
• Experience designing solutions that integrate a backend, database and Bitcoin node
• Production experience with Bitcoin wallet or custody infrastructure

Experience with TDD/BDD, Domain-Driven Design, monorepos and CI/CD environments is also highly valuable.

Interested? Please send your CV together with the following information:

• English level (B2 / C1 / C2);
• Total years of professional experience;
• Years of Java experience;
• Years of Bitcoin / BTC production experience;
• Current location / country;
• Citizenship;
• Availability / earliest possible start date;

Feel free to share this opportunity with someone who might be a good fit.