Nextcloud vs Seafile

Nextcloud and Seafile are the two names that come up first when people go looking for a self-hosted Dropbox, and they answer the question in opposite ways. Nextcloud is a collaboration platform that happens to start with files. Seafile is a file sync and share server, and it stays one. Neither is the better product in general — the right pick depends on whether you want a platform or a sync engine, and on one architectural detail that matters more than any feature list: how each one keeps your files on disk.

Two different jobs

Nextcloud: the platform

Nextcloud is a PHP application under the AGPL-3.0. Its Hub bundles Nextcloud Files with Talk (chat, calls and video conferencing), Groupware (calendar, contacts and mail), Office for real-time document collaboration, an AI assistant and Flow automation. If the plan is to replace Dropbox and a shared calendar and a video-call tool with one login, that is the pitch. The cost of the breadth is the stack: a PHP server with a real database behind it (upstream supports MariaDB, MySQL and PostgreSQL — Oracle only with an enterprise subscription — and calls SQLite "only recommended for testing and minimal-instances").

Seafile: the sync engine

Seafile's server core is written in C, with a Go file server and a Django web UI (Seahub). Its model is the library: a collection of files that syncs on its own schedule, so you pick which libraries each device gets. Seafile's README lists selective sync, conflict handling "based on history instead of timestamp", and uploads that "only transfer content delta to the server" and can be resumed if interrupted. There is a Drive client that mounts your libraries as a virtual drive and fetches files on demand, and a lightweight document editor (SeaDoc) — but no calendar, no mail, no chat. If "a fast, dependable Dropbox and nothing else" is the goal, that focus is the product.

How your files sit on disk

This is the difference that decides backups and exit plans, and it is easy to miss.

Nextcloud keeps each file as an ordinary file in its data directory. Its own occ files:scan documentation talks about "copying files directly into the data directory" — the data is plain files plus a database that indexes them.

Seafile does not. Its manual says files "are split to blocks, which means what are stored on your seafile server are not complete files, but blocks. This design faciliates effective data deduplication." You cannot browse the data directory and pick out a document; upstream provides seaf-fuse, a read-only FUSE mount, for administrators who need to see files on the server (encrypted libraries excluded). Two consequences follow. A backup must capture the three databases (ccnet_db, seafile_db, seahub_db) and the data directory, and upstream recommends dumping the databases first to avoid library corruption. And deleted files do not free space by themselves — blocks stay until you run Seafile's garbage collector, seaf-gc.sh.

Encryption

Both can keep a server admin out of your files, but they do it differently.

Seafile's encrypted libraries are set per library with a password. When you sync with the desktop client, encryption and decryption happen on the client and "the password of an encrypted library is not stored on the server". The manual is candid about the limits: file and folder names, sizes and edit history are not encrypted; opening an encrypted library in the web browser sends the password to the server, which caches it in memory for an hour; a library created in the web UI passes its keys through the server, so create it from the desktop client if you want end-to-end protection; and the iOS and Android clients dropped client-side encryption in version 3.0.0.

Nextcloud offers two separate features. Server-side encryption is off by default and, in upstream's words, "does not protect data from a compromised Nextcloud server or malicious administrator"; it also leaves file names and folder structure unencrypted. End-to-end encryption is the one that keeps an admin out: it is performed by the Nextcloud desktop or mobile clients before upload and needs the E2EE server app installed.

Community and Professional editions

Seafile ships in two editions, and the split is worth reading before you commit. The Community Edition is free and open source: the server core is AGPL-3.0 and Seahub is Apache-2.0. The Professional Edition is proprietary, runs "for 3 users" without a license file, and is paid beyond that. Seafile's own comparison table puts these on the Pro side only: full-text search, file locking, fine-grained folder permissions, syncing users and groups from LDAP/AD, ADFS single sign-on, role-based accounts, remote wipe, audit logs, antivirus integration, high availability and AWS S3 storage. The Community Edition keeps sync, mobile and Drive clients, sharing, version history, public links, LDAP/AD authentication, Shibboleth SSO, two-factor authentication, WebDAV, and OnlyOffice or Collabora integration.

For a household of three or fewer, Pro costs nothing; for a team, full-text search and folder-level permissions are the features most likely to push you toward a license.

Resources

Seafile's system requirements put the Community Edition at 2 GB of RAM and two cores, with 10 GB of disk and more than 50 GB recommended, and its default Docker deployment runs five containers — Seafile, MariaDB, Redis, SeaDoc and a Caddy reverse proxy. Pro wants 4 GB and four cores when it runs Elasticsearch on the same machine (its default), or 2 GB with the lighter SeaSearch engine. Nextcloud's manual asks for 128 MB per PHP process and recommends 512 MB; our catalog floor is 1 GB for a small instance, and it grows with the Hub apps you switch on.

Which should you self-host?

Pick Nextcloud if…

• You want files and calendar, contacts, mail, calls and office documents behind one login — a self-hosted replacement for more than Dropbox.
• You want your data directory to hold plain files rather than deduplicated blocks.
• You want end-to-end encryption on mobile as well as desktop — Nextcloud's E2EE runs in both clients, while Seafile's mobile apps no longer encrypt client-side.

Pick Seafile if…

• File sync is the whole job, and you want libraries synced selectively with delta, resumable uploads.
• Per-library encryption with a password the server never stores (on the desktop client) matches how you want to protect a few sensitive folders.
• You are comfortable with block storage: backups that must include the databases, and a garbage collector to run after deleting data.

We do not name a single winner here, because the two are built for different jobs. For a file-only Dropbox replacement, Seafile is the more focused tool; the moment calendar, contacts or calls are on the list, Nextcloud is the one that does all of it. If you are weighing Nextcloud against other file servers too, Nextcloud vs ownCloud covers the lean Go rewrite, Nextcloud vs OpenCloud its database-free continuation, and Syncthing vs Nextcloud covers serverless peer-to-peer sync; every option is on the Dropbox alternatives page.

Running either on a VPS

Both fit on a single small server for a household or small team. Size a Seafile box for its 2 GB Community floor (4 GB for Pro with Elasticsearch), and note that its Caddy container takes ports 80 and 443 — upstream documents how to swap in your own reverse proxy if something already holds them. The Nextcloud deploy guide walks through a full setup, and the Nextcloud and Seafile pages have the install snippets. Whichever you pick, test a restore before you trust the backup — with Seafile, a restore that is missing the databases is a restore of blocks you cannot open.