Another property that we encounter is that blockchain is append-only, which means that data can only be added to the blockchain in time-ordered sequential order.
This property implies that once data is added to the blockchain, it is almost impossible to change that data and can be considered practically immutable.
Why Blockchain Data Can Never Be Deleted or Altered
Nonetheless, it can be changed in rare scenarios wherein collusion against the blockchain network succeeds in gaining more than 51 percent of the power.
There may be some legitimate reasons to change data in the blockchain once it has been added, such as the right to be forgotten or right to erasure (also defined in General Data Protection (GDPR) ruling, ).
For all practical purposes, blockchain is indeed immutable and cannot be changed.
Why This Matters for Blockchain Technology
Understanding Append-only is not just an academic exercise — it has real-world implications for how blockchain systems are designed, deployed, and secured. Whether you are a developer building decentralized applications, a business leader evaluating blockchain adoption, or a curious learner exploring the technology, this knowledge provides a critical foundation.
Key Points to Remember
- Append-only Another property that we encounter is that blockchain is append-only, which means that data can only be added to the blockchain in time-ordered sequential order.
- This property implies that once data is added to the blockchain, it is almost impossible to change that data and can be considered practically immutable.
- Nonetheless, it can be changed in rare scenarios wherein collusion against the blockchain network succeeds in gaining more than 51 percent of the power.
- There may be some legitimate reasons to change data in the blockchain once it has been added, such as the right to be forgotten or right to erasure (also defined in General Data Protection (GDPR) ruling, ).
Conclusion
Append-only represents one of the many innovative layers that make blockchain technology so powerful and transformative. As distributed systems continue to evolve, a solid understanding of these core concepts becomes increasingly valuable — not just for developers, but for anyone building, investing in, or working alongside blockchain-powered systems.
Whether you are just starting your blockchain journey or deepening existing expertise, mastering these fundamentals gives you the tools to think clearly about decentralized systems and make smarter decisions in this rapidly evolving space.