A blockchain developer is a professional who specializes in creating and implementing blockchain technology. They are responsible for designing, developing, and maintaining blockchain-based applications and systems.

As for the 15 features/advantages of a blockchain developer, here are some key ones:

1. Expertise in blockchain technology: A blockchain developer possesses in-depth knowledge and understanding of blockchain concepts, protocols, and frameworks.

2. Smart contract development: They can create and deploy smart contracts, which are self-executing contracts with predefined rules and conditions.

3. Decentralization: Blockchain developers understand the importance of decentralization and can design systems that eliminate the need for intermediaries.

4. Security: They prioritize security measures to protect data and transactions on the blockchain.

5. Transparency: Blockchain developers can ensure transparency by creating systems that allow participants to view and verify transactions.

6. Immutability: They can design blockchain systems that make it nearly impossible to alter or tamper with recorded data.

7. Scalability: Blockchain developers can optimize blockchain networks to handle a large number of transactions and users.

8. Interoperability: They can create blockchain systems that can communicate and interact with other blockchain networks.

9. Privacy: Blockchain developers can implement privacy features to protect sensitive information while maintaining transparency.

10. Consensus mechanisms: They understand different consensus algorithms and can choose the most suitable one for a specific blockchain application.

11. Tokenization: They can create and manage tokens on the blockchain, enabling the development of decentralized applications (DApps).

12. Auditability: Blockchain developers can design systems that allow for easy auditing and verification of transactions.

13. Cost efficiency: They can develop blockchain solutions that reduce costs by eliminating intermediaries and streamlining processes.

14. Traceability: They can create systems that enable the tracking and tracing of goods and transactions on the blockchain.

15. Innovation: Blockchain developers are at the forefront of technological advancements and can contribute to the development of new blockchain-based solutions.