W3C’s 2015 Recommendation for reading and writing resources over plain HTTP. LDP defines containers that behave like directories, creates members with POST, writes with PUT and PATCH, requires ETag preconditions on updates, and treats non-RDF resources — files — as first-class members. It is the standards-track answer to “a file system over HTTP” that most people have never heard of, and the foundation Solid builds on.
Linked Data Platform
Linked Data Platform is a W3C Recommendation that says how a client reads, creates, updates and deletes resources using nothing but HTTP methods and headers. The headline is RDF, but the useful half is the container model: a container is a resource that lists its members, a POST to it creates a new member, and the server tells you what it created in a Location header. That is a directory. LDP just never called it one.
- Three container types - Basic containers hold members directly; direct and indirect containers let the membership triples live on another resource. Basic is the one that behaves like a folder.
- Preconditions are required - Servers MUST support
If-MatchonPUT, and clients SHOULD send it. The lost-update problem is handled with ETags, not locks. - Non-RDF sources - Any binary — a PDF, an image, a CSV — is an LDP-NR and a full member of a container, with its metadata on a separate RDF resource linked by
describedby. Preferand paging - A client asks for a container with or without its membership listing viaPrefer, and large containers page withfirst/nextlinks instead of one enormous response.
I keep LDP in the catalog as the clean, standards-track statement of a pattern the industry keeps re-inventing: a namespace of resources you can walk, write into, and guard against concurrent writers, using only HTTP. It is what WebDAV did with new verbs, done instead with the verbs HTTP already had. When the Model Context Protocol working groups set out in 2026 to make resources writable with create, delete, stat and optimistic concurrency, they were specifying LDP’s container semantics inside JSON-RPC, and LDP is the shortest document that shows what a complete answer looks like. The Solid Protocol is where it went next.
