diff --git a/light9/web/graph.coffee b/light9/web/graph.coffee
new file mode 100644
--- /dev/null
+++ b/light9/web/graph.coffee
@@ -0,0 +1,148 @@
+# Patch is {addQuads: <quads>, delQuads: <quads>}
+# <quads> is [{subject: s, ...}, ...]
+
+# partial port of autodepgraphapi.py
+class GraphWatchers
+  constructor: ->
+    @handlersSp = {} # {s: {p: [handlers]}}
+  subscribe: (s, p, o, onChange) -> # return subscription handle
+    if o? then throw Error('not implemented')
+    if not @handlersSp[s]
+      @handlersSp[s] = {}
+    if not @handlersSp[s][p]
+      @handlersSp[s][p] = []
+    @handlersSp[s][p].push(onChange)
+    
+  unsubscribe: (subscription) ->
+    throw Error('not implemented')
+    
+  graphChanged: (patch) ->
+    for quad in patch.delQuads
+      for cb in ((@handlersSp[quad.subject] || {})[quad.predicate] || [])
+        # currently calls multiple times, which is ok, but we might
+        # group things into fewer patches
+        cb({delQuads: [quad], addQuads: []})
+    for quad in patch.addQuads
+      for cb in ((@handlersSp[quad.subject] || {})[quad.predicate] || [])
+        cb({delQuads: [], addQuads: [quad]})
+
+
+class window.SyncedGraph
+  # Note that applyPatch is the only method to write to the graph, so
+  # it can fire subscriptions.
+
+  constructor: (patchSenderUrl, prefixes) ->
+    @graph = N3.Store()
+    @_addPrefixes(prefixes)
+    @_watchers = new GraphWatchers()
+
+  _addPrefixes: (prefixes) ->
+    @graph.addPrefixes(prefixes)
+        
+  Uri: (curie) ->
+    N3.Util.expandPrefixedName(curie, @graph._prefixes)
+
+  Literal: (jsValue) ->
+    N3.Util.createLiteral(jsValue)
+
+  toJs: (literal) ->
+    # incomplete
+    parseFloat(N3.Util.getLiteralValue(literal))
+
+  loadTrig: (trig, cb) -> # for debugging
+    patch = {delQuads: [], addQuads: []}
+    parser = N3.Parser()
+    parser.parse trig, (error, quad, prefixes) =>
+                  if (quad)
+                    patch.addQuads.push(quad)
+                  else
+                    @applyPatch(patch)
+                    @_addPrefixes(prefixes)
+                    cb() if cb
+                    
+  quads: () -> # for debugging
+    [q.subject, q.predicate, q.object, q.graph] for q in @graph.find()
+
+  applyAndSendPatch: (patch, cb) ->
+    @applyPatch(patch)
+    console.log('patch to server:', patch)
+    # post to server
+
+  applyPatch: (patch) ->
+    # In most cases you want applyAndSendPatch.
+    # 
+    # This is the only method that writes to the graph!
+    for quad in patch.delQuads
+      @graph.removeTriple(quad)
+    for quad in patch.addQuads
+      @graph.addTriple(quad)
+    @_watchers.graphChanged(patch)
+
+  getObjectPatch: (s, p, newObject, g) ->
+    # send a patch which removes existing values for (s,p,*,c) and
+    # adds (s,p,newObject,c). Values in other graphs are not affected.
+    existing = @graph.findByIRI(s, p, null, g)
+    return {
+      delQuads: existing,
+      addQuads: [{subject: s, predicate: p, object: newObject, graph: g}]
+    }
+
+  patchObject: (s, p, newObject, g) ->
+    @applyAndSendPatch(@getObjectPatch(s, p, newObject, g))
+  
+
+  subscribe: (s, p, o, onChange) -> # return subscription handle
+    # onChange is called with a patch that's limited to the quads
+    # that match your request.
+    # We call you immediately on existing triples.
+    @_watchers.subscribe(s, p, o, onChange)
+    immediatePatch = {delQuads: [], addQuads: @graph.findByIRI(s, p, o)}
+    if immediatePatch.addQuads.length
+      onChange(immediatePatch)
+
+  unsubscribe: (subscription) ->
+    @_watchers.unsubscribe(subscription)
+
+  floatValue: (s, p) ->
+    quads = @graph.findByIRI(s, p)
+    switch quads.length
+      when 0 then throw new Error("no value for "+s+" "+p)
+      when 1
+        obj = quads[0].object
+        return parseFloat(N3.Util.getLiteralValue(obj))
+      else
+        throw new Error("too many values: " + JSON.stringify(quads))
+    
+  stringValue: (s, p) ->
+
+  uriValue: (s, p) ->
+
+  objects: (s, p) ->
+
+  subjects: (p, o) ->
+
+  items: (list) ->
+
+  contains: (s, p, o) ->
+
+###
+rdfstore.create((err, store) ->
+  window.store = store
+  store.setPrefix('l9', "http://light9.bigasterisk.com/")
+  store.setPrefix('xsd', "http://www.w3.org/2001/XMLSchema#")
+  store.load('text/turtle', "
+@prefix : <http://light9.bigasterisk.com/> .
+@prefix dev: <http://light9.bigasterisk.com/device/> .
+
+:demoResource :startTime 0.5 .
+    ", (err, n) ->
+      console.log('loaded', n)
+      store.graph (err, graph) ->
+        window.graph = graph
+        
+    )
+  window.URI = (curie) -> store.rdf.createNamedNode(store.rdf.resolve(curie))
+  window.Lit = (value, dtype) -> store.rdf.createLiteral(value, null, URI(dtype))
+
+  )
+###
\ No newline at end of file