Register endpoints, write SPARQL, and let FedX do the work.
The example returns up to 10 matches from your selected endpoints.
Run a query to see its response.
Run a query to capture its plan, or choose Show plan.
Actual outgoing SPARQL, including source-selection ASK queries and runtime bindings.
Your endpoint changes haven’t been saved.
Quick add
Public endpoints · select to add
This clears all endpoints, bearer tokens, saved queries, query tabs, results, and settings in this browser tab and its saved workspace. Any running query will be stopped.
The page will reload with the default endpoints, example query, and settings. Export your workspace first if you want to keep it. This cannot be undone.
Turn it on to suggest SPARQL terms from the endpoints you select in the sidebar.
Ctrl + Space opens suggestions. Typing ? suggests variables. Use the arrow keys and Enter to insert a suggestion. Shift + Space also opens suggestions.
Place the cursor after a subject to suggest predicates, or after a predicate to suggest values. Selected endpoint presets also offer prefix shortcuts.
Hover a variable for a local explanation, or an IRI for a label lookup. “Matched selected federation” means FedX evaluated the suggestion against your supported query context. It does not identify which endpoint contributed each part of a join.
Progress, unsupported contexts, and endpoint failures appear below the editor. Suggestions never fall back to a broader query. Suggestions are examples, not complete results or proof that your query is valid.
Known prefixes are added automatically while this is on. Underlines show editing diagnostics; use the lightbulb for quick fixes and query-building actions. These checks do not replace validation by FedX.
Use F2 to rename a variable, or the editor context menu to find references. Query blocks can fold, and Enter, semicolon and period format valid triples as you type. Turn this off to stop all authoring assistance.
RDF4J / FedX 6.1.0 runs in WebAssembly in an isolated worker. Queries go directly to your endpoints.
Saved queries and endpoint settings stay in local browser storage. Results are not saved. Export a workspace backup before clearing browser data.
Large joins can still consume engine heap beyond the input/output budgets. Browser cancellation terminates the worker; it cannot guarantee cancellation of work already running on a remote server.