Is XRPL centralized? The UNL mechanism sparks a major debate in the crypto community

Cyber Capital founder Justin Bons criticized XRPL on X platform, claiming that its unique node list (UNL) mechanism requires validators to obtain permission, calling it a “centralized blockchain”; Ripple’s Chief Technology Officer David Schwartz publicly rebutted, emphasizing that XRPL’s design is intended to prevent any single entity from controlling the network, including Ripple itself.

Justin Bons’s Centralization Allegation: UNL Mechanism is the Core Issue

Cyber Capital founder and CTO Justin Bons focused his criticism on XRPL’s UNL mechanism: any node deviating from Ripple’s published list could cause a fork, which in practice grants Ripple and its foundation substantial control over the blockchain.

Bons adopts a strict binary framework: blockchains are either fully permissionless (based on PoS or PoW) or inherently permissioned (PoA). He classifies systems that do not fit PoS or PoW as PoA, grouping XRPL with Stellar (XLM), Hedera, Algorand, and others into the “centralized permissioned chains,” pointing out that “trusting someone is not the same as being completely trustless.”

David Schwartz’s Rebuttal: Architecture Designed to Prevent Centralization

Ripple CTO David Schwartz responded from a technical architecture perspective. He pointed out that Ripple intentionally designed XRPL to be resistant to control by any single entity, partly motivated by regulatory considerations—since Ripple is a US-regulated company, it does not want to hold network control that could be enforced by courts.

Regarding double-spending and censorship allegations, Schwartz’s logic is as follows: XRPL reaches consensus roughly every five seconds, with each node independently following protocol rules and only considering validators in its own UNL. If a validator acts dishonestly, honest nodes can regard it as untrusted. Schwartz admits that validators could theoretically collude to disrupt the network, but this cannot result in double-spending, and the solution is to switch to a new UNL.

He further compares: “Bitcoin transactions are often censored, Ethereum transactions have been maliciously altered or censored, but XRPL transactions have never experienced such issues, and it’s hard to imagine how they could.”

Core Points of Schwartz’s Rebuttal

UNL is user-selected, not Ripple-mandated: Each node independently chooses which validators to trust; Ripple cannot force other nodes to adopt its published list.

Double-spending cannot be achieved: Validators cannot force honest nodes to accept double-spending; any attempt to censor or double-spend will immediately and permanently damage trust in XRPL.

Rationale for validator count design: Limiting the number of validators prevents malicious actors from attacking consensus with fake nodes, ensuring the network can determine whether consensus is truly reached.

Historical record evidence: Compared to Bitcoin and Ethereum, XRPL has no record of censorship or malicious tampering.

Frequently Asked Questions

What is the Unique Node List (UNL) in XRPL, and why does it spark decentralization debates?

UNL is a list each XRPL node uses to decide which validators to trust. Ripple and the XRPL Foundation publish their recommended lists, but technically, any node can choose its own set of validators. Critics argue that most nodes follow Ripple’s recommended list, leading to practical centralization; supporters believe that the autonomy of node choices is a core decentralization feature of XRPL.

Can Ripple exert substantial control over transactions on XRPL?

According to Schwartz’s technical explanation, Ripple cannot force honest nodes to accept double-spending or censorship. If Ripple attempts to do so, it would permanently damage trust in the network. The system’s incentive mechanisms are designed to prevent such control. Honest nodes can respond by switching to a different UNL to exclude untrustworthy validators.

Does Justin Bons’s classification of XRPL as centralized reflect industry consensus?

No, this disagreement highlights that there is no unified standard in the industry for defining decentralization. Bons’s strict binary framework (PoS or PoW as decentralized) contrasts with supporters who believe that actual resistance to censorship and control distribution are better measures. This debate is part of broader discussions on blockchain decentralization standards, which currently lack an industry-wide consensus.