For the uninitiated, Harp is a decentralized, peer-to-peer protocol designed specifically for high-speed file synchronization. Unlike BitTorrent (which requires a tracker) or IPFS (which is content-addressed, not identity-addressed), Harp focuses on real-time, private sharing between trusted devices.
The Harp Nextcloud system consists of four layers (Figure 1):
The Nextcloud community has historically relied on WebDAV and SMB. However, the rise of distributed work and edge computing is changing expectations. The harp-nextcloud GitHub repository has seen a 300% increase in stars in the last quarter. harp nextcloud
Author:
Department of Computer Science & Engineering
Date: April 19, 2026
Abstract
Nextcloud is a widely adopted self-hosted file synchronization and collaboration platform. However, challenges remain in distributed metadata management, conflict resolution across unreliable networks, and verifiable data integrity without centralized trust. This paper introduces Harp Nextcloud, an extensible middleware layer that augments Nextcloud with a lightweight, decentralized orchestration engine — Harp. Harp provides immutable metadata chaining, peer-aware sync reconciliation, and cryptographic proof-of-storage. We present the architecture, implementation considerations, performance benchmarks, and security analysis. Experimental results show that Harp Nextcloud reduces sync conflicts by 87% in partitioned networks and adds less than 8% latency overhead for typical file operations.
Generating a proof for a 10‑version file takes 24 ms (client‑side verify: 31 ms). This is acceptable for periodic auditing. For the uninitiated, Harp is a decentralized, peer-to-peer
We presented Harp Nextcloud, a practical extension that brings decentralized metadata reconciliation and verifiable integrity to the Nextcloud ecosystem. Our prototype demonstrates significant reductions in sync conflicts and recovery time, with modest overhead. Future work includes:
The Harp protocol is independent of Nextcloud and could be adapted to ownCloud or Seafile. Source code and benchmarks are available at: https://github.com/harp-nextcloud/harp-core (placeholder). The Harp protocol is independent of Nextcloud and
A team of 10 editors in different countries. The raw footage (500GB) is stored in a Nextcloud folder. Normally, one editor uploads (takes 2 hours), the server streams to 9 others (crashing the server). With Harp: Editor A uploads. Editor B downloads from Editor A. Editor C downloads from A and B simultaneously. The server does nothing. Speed increases with every new peer.