diff --git a/benchmark/benchmark-suite.coffee b/benchmark/benchmark-suite.coffee
index 2b8bec8ba..b5401d385 100644
--- a/benchmark/benchmark-suite.coffee
+++ b/benchmark/benchmark-suite.coffee
@@ -123,6 +123,41 @@ describe "editor.", ->
         div = document.createElement('div')
         div.innerHTML = html
 
+    describe "gutter-api.", ->
+      describe "getLineNumberElementsForClass.", ->
+        beforeEach ->
+          editor.gutter.addClassToLine(20, 'omgwow')
+          editor.gutter.addClassToLine(40, 'omgwow')
+
+        benchmark "DOM", 20000, ->
+          editor.gutter.getLineNumberElementsForClass('omgwow')
+
+      benchmark "getLineNumberElement.DOM", 20000, ->
+        editor.gutter.getLineNumberElement(12)
+
+      benchmark "toggle-class", 2000, ->
+        editor.gutter.addClassToLine(40, 'omgwow')
+        editor.gutter.removeClassFromLine(40, 'omgwow')
+
+      describe "find-then-unset.", ->
+        classes = ['one', 'two', 'three', 'four']
+
+        benchmark "single-class", 200, ->
+          editor.gutter.addClassToLine(30, 'omgwow')
+          editor.gutter.addClassToLine(40, 'omgwow')
+          editor.gutter.removeClassFromAllLines('omgwow')
+
+        benchmark "multiple-class", 200, ->
+          editor.gutter.addClassToLine(30, 'one')
+          editor.gutter.addClassToLine(30, 'two')
+
+          editor.gutter.addClassToLine(40, 'two')
+          editor.gutter.addClassToLine(40, 'three')
+          editor.gutter.addClassToLine(40, 'four')
+
+          for klass in classes
+            editor.gutter.removeClassFromAllLines(klass)
+
     describe "line-htmlification.", ->
       div = null
       html = null
diff --git a/package.json b/package.json
index 6f7c8410e..97e1e87a4 100644
--- a/package.json
+++ b/package.json
@@ -46,7 +46,7 @@
     "archive-view": "0.8.0",
     "autocomplete": "0.6.0",
     "autoflow": "0.3.0",
-    "bookmarks": "0.4.0",
+    "bookmarks": "0.5.0",
     "bracket-matcher": "0.6.0",
     "collaboration": "0.20.0",
     "command-logger": "0.4.0",
@@ -56,7 +56,7 @@
     "find-and-replace": "0.24.0",
     "fuzzy-finder": "0.7.0",
     "gfm": "0.5.0",
-    "git-diff": "0.4.0",
+    "git-diff": "0.5.0",
     "gists": "0.3.0",
     "github-sign-in": "0.7.0",
     "go-to-line": "0.4.0",
diff --git a/spec/editor-spec.coffee b/spec/editor-spec.coffee
index e407048cb..48de79f12 100644
--- a/spec/editor-spec.coffee
+++ b/spec/editor-spec.coffee
@@ -1886,6 +1886,49 @@ describe "Editor", ->
         config.set("editor.showLineNumbers", false)
         expect(editor.gutter.lineNumbers).not.toBeVisible()
 
+    describe "using gutter's api", ->
+      it "can get all the line number elements", ->
+        elements = editor.gutter.getLineNumberElements()
+        len = editor.gutter.lastScreenRow - editor.gutter.firstScreenRow + 1
+        expect(elements).toHaveLength(len)
+
+      it "can get a single line number element", ->
+        element = editor.gutter.getLineNumberElement(3)
+        expect(element).toBeTruthy()
+
+      it "returns falsy when there is no line element", ->
+        expect(editor.gutter.getLineNumberElement(42)).toHaveLength 0
+
+      it "can add and remove classes to all the line numbers", ->
+        wasAdded = editor.gutter.addClassToAllLines('heyok')
+        expect(wasAdded).toBe true
+
+        elements = editor.gutter.getLineNumberElementsForClass('heyok')
+        expect($(elements)).toHaveClass('heyok')
+
+        editor.gutter.removeClassFromAllLines('heyok')
+        expect($(editor.gutter.getLineNumberElements())).not.toHaveClass('heyok')
+
+      it "can add and remove classes from a single line number", ->
+        wasAdded = editor.gutter.addClassToLine(3, 'heyok')
+        expect(wasAdded).toBe true
+
+        element = editor.gutter.getLineNumberElement(2)
+        expect($(element)).not.toHaveClass('heyok')
+
+      it "can fetch line numbers by their class", ->
+        editor.gutter.addClassToLine(1, 'heyok')
+        editor.gutter.addClassToLine(3, 'heyok')
+
+        elements = editor.gutter.getLineNumberElementsForClass('heyok')
+        expect(elements.length).toBe 2
+
+        expect($(elements[0])).toHaveClass 'line-number-1'
+        expect($(elements[0])).toHaveClass 'heyok'
+
+        expect($(elements[1])).toHaveClass 'line-number-3'
+        expect($(elements[1])).toHaveClass 'heyok'
+
   describe "gutter line highlighting", ->
     beforeEach ->
       editor.attachToDom(heightInLines: 5.5)
diff --git a/src/gutter.coffee b/src/gutter.coffee
index 0fb2ae9a3..1e38daa7a 100644
--- a/src/gutter.coffee
+++ b/src/gutter.coffee
@@ -62,6 +62,76 @@ class Gutter extends View
   setShowLineNumbers: (showLineNumbers) ->
     if showLineNumbers then @lineNumbers.show() else @lineNumbers.hide()
 
+  # Get all the line-number divs.
+  #
+  # Returns a list of {HTMLElement}s.
+  getLineNumberElements: ->
+    @lineNumbers[0].childNodes
+
+  # Get all the line-number divs.
+  #
+  # Returns a list of {HTMLElement}s.
+  getLineNumberElementsForClass: (klass) ->
+    @lineNumbers[0].getElementsByClassName(klass)
+
+  # Get a single line-number div.
+  #
+  # * bufferRow: 0 based line number
+  #
+  # Returns a list of {HTMLElement}s that correspond to the bufferRow. More than
+  # one in the list indicates a wrapped line.
+  getLineNumberElement: (bufferRow) ->
+    @getLineNumberElementsForClass("line-number-#{bufferRow}")
+
+  # Add a class to all line-number divs.
+  #
+  # * klass: string class name
+  #
+  # Returns true if the class was added to any lines
+  addClassToAllLines: (klass)->
+    elements = @getLineNumberElements()
+    el.classList.add(klass) for el in elements
+    !!elements.length
+
+  # Remove a class from all line-number divs.
+  #
+  # * klass: string class name. Can only be one class name. i.e. 'my-class'
+  #
+  # Returns true if the class was removed from any lines
+  removeClassFromAllLines: (klass)->
+    # This is faster than calling $.removeClass on all lines, and faster than
+    # making a new array and iterating through it.
+    elements = @getLineNumberElementsForClass(klass)
+    willRemoveClasses = !!elements.length
+    elements[0].classList.remove(klass) while elements.length > 0
+    willRemoveClasses
+
+  # Add a class to a single line-number div
+  #
+  # * bufferRow: 0 based line number
+  # * klass: string class name
+  #
+  # Returns true if there were lines the class was added to
+  addClassToLine: (bufferRow, klass)->
+    elements = @getLineNumberElement(bufferRow)
+    el.classList.add(klass) for el in elements
+    !!elements.length
+
+  # Remove a class from a single line-number div
+  #
+  # * bufferRow: 0 based line number
+  # * klass: string class name
+  #
+  # Returns true if there were lines the class was removed from
+  removeClassFromLine: (bufferRow, klass)->
+    classesRemoved = false
+    elements = @getLineNumberElement(bufferRow)
+    for el in elements
+      hasClass = el.classList.contains(klass)
+      classesRemoved |= hasClass
+      el.classList.remove(klass) if hasClass
+    classesRemoved
+
   ### Internal ###
 
   updateLineNumbers: (changes, renderFrom, renderTo) ->
@@ -96,12 +166,12 @@ class Gutter extends View
       else
         rowValue = (row + 1).toString()
 
-      classes = 'line-number'
+      classes = "line-number line-number-#{row}"
       classes += ' fold' if editor.isFoldedAtBufferRow(row)
 
       rowValuePadding = _.multiplyString(' ', maxDigits - rowValue.length)
 
-      html += """<div class="#{classes}" lineNumber="#{row}">#{rowValuePadding}#{rowValue}</div>"""
+      html += """<div class="#{classes}">#{rowValuePadding}#{rowValue}</div>"""
 
       lastScreenRow = row