diff --git a/CHANGELOG.md b/CHANGELOG.md
index 598c57ac..685a89f0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 master
 ===
 
+* Incremental builds: `--track-dependencies` and `--only-changed` flags (#2220)
 * Remove Rack support in favor of `resource.filters << proc { |oldbody| newbody }`
 * `manipulate_resource_list_container!` as a faster, less functional approach.
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 3ad30134..15430724 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,13 +1,13 @@
 PATH
   remote: middleman-cli
   specs:
-    middleman-cli (4.3.0.rc.4)
+    middleman-cli (5.0.0.rc.1)
       thor (>= 0.17.0, < 2.0)
 
 PATH
   remote: middleman-core
   specs:
-    middleman-core (4.3.0.rc.4)
+    middleman-core (5.0.0.rc.1)
       activesupport (>= 4.2, < 5.2)
       addressable (~> 2.3)
       backports (~> 3.11)
diff --git a/LICENSE.md b/LICENSE.md
index a506b74f..faa6d6c7 100644
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -1,4 +1,4 @@
-Copyright (c) 2010-2017 Thomas Reynolds
+Copyright (c) 2010-2018 Thomas Reynolds
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
diff --git a/middleman-cli/lib/middleman-cli/build.rb b/middleman-cli/lib/middleman-cli/build.rb
index 41253290..350a75c9 100644
--- a/middleman-cli/lib/middleman-cli/build.rb
+++ b/middleman-cli/lib/middleman-cli/build.rb
@@ -36,6 +36,18 @@ module Middleman::Cli
                  type: :boolean,
                  default: false,
                  desc: 'Generate profiling report for the build'
+    class_option :track_dependencies,
+                 type: :boolean,
+                 default: false,
+                 desc: 'Track file dependencies'
+    class_option :only_changed,
+                 type: :boolean,
+                 default: false,
+                 desc: 'Only build changed files'
+    class_option :missing_and_changed,
+                 type: :boolean,
+                 default: false,
+                 desc: 'Only build changed files or files missing from build folder'
 
     Middleman::Cli.import_config(self)
 
@@ -71,7 +83,10 @@ module Middleman::Cli
         builder = Middleman::Builder.new(@app,
                                          glob: options['glob'],
                                          clean: options['clean'],
-                                         parallel: options['parallel'])
+                                         parallel: options['parallel'],
+                                         only_changed: options['only_changed'],
+                                         missing_and_changed: options['missing_and_changed'],
+                                         track_dependencies: options['track_dependencies'])
         builder.thor = self
         builder.on_build_event(&method(:on_event))
       end
@@ -108,6 +123,8 @@ module Middleman::Cli
         say_status :create, target, :green
       when :identical
         say_status :identical, target, :blue
+      when :skipped
+        say_status :skipped, target, :blue
       when :updated
         say_status :updated, target, :yellow
       else
diff --git a/middleman-core/features/extension_hooks.feature b/middleman-core/features/extension_hooks.feature
index ae89dfec..12e0eacc 100644
--- a/middleman-core/features/extension_hooks.feature
+++ b/middleman-core/features/extension_hooks.feature
@@ -5,6 +5,4 @@ Feature: Extension author could use some hooks
     And the output should contain "/// after_configuration ///"
     And the output should contain "/// ready ///"
     And the output should contain "/// before_build ///"
-    And the output should contain "/// before_render ///"
-    And the output should contain "/// after_render ///"
     And the output should contain "/// after_build ///"
diff --git a/middleman-core/fixtures/extension-hooks-app/config.rb b/middleman-core/fixtures/extension-hooks-app/config.rb
index d0769b81..4a81dda3 100644
--- a/middleman-core/fixtures/extension-hooks-app/config.rb
+++ b/middleman-core/fixtures/extension-hooks-app/config.rb
@@ -12,14 +12,6 @@ class MyFeature < Middleman::Extension
       puts '/// ready ///'
     end
 
-    app.before_render do |_body, _path, _locs, _template_class|
-      puts '/// before_render ///'
-    end
-
-    app.after_render do |_content, _path, _locs, _template_class|
-      puts '/// after_render ///'
-    end
-
     app.before_build do |_builder|
       puts '/// before_build ///'
     end
diff --git a/middleman-core/fixtures/more-preview-app/source/stylesheets/_below_partial.sass b/middleman-core/fixtures/more-preview-app/source/stylesheets/_below_partial.sass
new file mode 100644
index 00000000..f3b95765
--- /dev/null
+++ b/middleman-core/fixtures/more-preview-app/source/stylesheets/_below_partial.sass
@@ -0,0 +1,2 @@
+footer
+  font-size: 1px
\ No newline at end of file
diff --git a/middleman-core/fixtures/more-preview-app/source/stylesheets/_partial.sass b/middleman-core/fixtures/more-preview-app/source/stylesheets/_partial.sass
index 3b0e67db..2b171ed9 100644
--- a/middleman-core/fixtures/more-preview-app/source/stylesheets/_partial.sass
+++ b/middleman-core/fixtures/more-preview-app/source/stylesheets/_partial.sass
@@ -1,2 +1,4 @@
+@import below_partial.sass
+
 body
   font-size: 18px
\ No newline at end of file
diff --git a/middleman-core/fixtures/more-preview-app/source/stylesheets/also_needs_partial.css.scss b/middleman-core/fixtures/more-preview-app/source/stylesheets/also_needs_partial.css.scss
new file mode 100644
index 00000000..139fe81a
--- /dev/null
+++ b/middleman-core/fixtures/more-preview-app/source/stylesheets/also_needs_partial.css.scss
@@ -0,0 +1,5 @@
+@import "partial.sass";
+
+blue {
+  color: red;
+}
\ No newline at end of file
diff --git a/middleman-core/lib/middleman-core/application.rb b/middleman-core/lib/middleman-core/application.rb
index 8484d721..3e8191a6 100644
--- a/middleman-core/lib/middleman-core/application.rb
+++ b/middleman-core/lib/middleman-core/application.rb
@@ -237,8 +237,6 @@ module Middleman
                                       :after_build,
                                       :before_shutdown,
                                       :before, # Before Rack requests
-                                      :before_render,
-                                      :after_render,
                                       :before_server,
                                       :reload
                                     ])
diff --git a/middleman-core/lib/middleman-core/builder.rb b/middleman-core/lib/middleman-core/builder.rb
index 1316fbc0..eeceaf8e 100644
--- a/middleman-core/lib/middleman-core/builder.rb
+++ b/middleman-core/lib/middleman-core/builder.rb
@@ -2,6 +2,7 @@ require 'pathname'
 require 'fileutils'
 require 'tempfile'
 require 'parallel'
+require 'middleman-core/dependencies'
 require 'middleman-core/callback_manager'
 require 'middleman-core/contracts'
 
@@ -33,8 +34,11 @@ module Middleman
       raise ":build_dir (#{@build_dir}) cannot be a parent of :source_dir (#{@source_dir})" if /\A[.\/]+\Z/.match?(@build_dir.expand_path.relative_path_from(@source_dir).to_s)
 
       @glob = options_hash.fetch(:glob)
-      @cleaning = options_hash.fetch(:clean)
       @parallel = options_hash.fetch(:parallel, true)
+      @only_changed = options_hash.fetch(:only_changed, false)
+      @missing_and_changed = !@only_changed && options_hash.fetch(:missing_and_changed, false)
+      @track_dependencies = @only_changed || @missing_and_changed || options_hash.fetch(:track_dependencies, false)
+      @cleaning = options_hash.fetch(:clean)
 
       @callbacks = ::Middleman::CallbackManager.new
       @callbacks.install_methods!(self, [:on_build_event])
@@ -47,6 +51,24 @@ module Middleman
       @has_error = false
       @events = {}
 
+      if @track_dependencies
+        begin
+          @graph = ::Middleman::Dependencies.load_and_deserialize(@app)
+        rescue ::Middleman::Dependencies::InvalidDepsYAML
+          logger.error 'dep.yml was corrupt. Dependency graph must be rebuilt.'
+          @graph = ::Middleman::Dependencies::Graph.new
+          @only_changed = @missing_and_changed = false
+        rescue ::Middleman::Dependencies::InvalidatedRubyFiles => e
+          changed = e.invalidated.map { |f| f[:file] }.join(', ')
+          logger.error "Some ruby files (#{changed}) have changed since last run. Dependency graph must be rebuilt."
+
+          @graph = ::Middleman::Dependencies::Graph.new
+          @only_changed = @missing_and_changed = false
+        end
+      end
+
+      @invalidated_files = @graph.invalidated if @only_changed || @missing_and_changed
+
       ::Middleman::Util.instrument 'builder.before' do
         @app.execute_callbacks(:before_build, [self])
       end
@@ -56,18 +78,34 @@ module Middleman
       end
 
       ::Middleman::Util.instrument 'builder.prerender' do
-        prerender_css
+        prerender_css.tap do |resources|
+          if @track_dependencies
+            resources.each do |r|
+              dependency = r[1]
+              @graph.add_dependency(dependency) unless dependency.nil?
+            end
+          end
+        end
       end
 
       ::Middleman::Profiling.start
 
       ::Middleman::Util.instrument 'builder.output' do
-        output_files
+        output_files.tap do |resources|
+          if @track_dependencies
+            resources.each do |r|
+              dependency = r[1]
+              @graph.add_dependency(dependency) unless dependency.nil?
+            end
+          end
+        end
       end
 
       ::Middleman::Profiling.report('build')
 
       unless @has_error
+        ::Middleman::Dependencies.serialize_and_save(@app, @graph) if @track_dependencies
+
         ::Middleman::Util.instrument 'builder.clean' do
           clean! if @cleaning
         end
@@ -82,12 +120,14 @@ module Middleman
 
     # Pre-request CSS to give Compass a chance to build sprites
     # @return [Array<Resource>] List of css resources that were output.
-    Contract ResourceList
+    Contract ArrayOf[[Pathname, Maybe[::Middleman::Dependencies::Dependency]]]
     def prerender_css
       logger.debug '== Prerendering CSS'
 
+      resources = @app.sitemap.by_extension('.css').to_a
+
       css_files = ::Middleman::Util.instrument 'builder.prerender.output' do
-        output_resources(@app.sitemap.by_extension('.css').to_a)
+        output_resources(resources)
       end
 
       ::Middleman::Util.instrument 'builder.prerender.check-files' do
@@ -103,7 +143,7 @@ module Middleman
 
     # Find all the files we need to output and do so.
     # @return [Array<Resource>] List of resources that were output.
-    Contract OldResourceList
+    Contract ArrayOf[[Pathname, Maybe[::Middleman::Dependencies::Dependency]]]
     def output_files
       logger.debug '== Building files'
 
@@ -112,20 +152,10 @@ module Middleman
       resources = non_css_resources
                   .sort_by { |resource| SORT_ORDER.index(resource.ext) || 100 }
 
-      if @glob
-        resources = resources.select do |resource|
-          if defined?(::File::FNM_EXTGLOB)
-            File.fnmatch(@glob, resource.destination_path, ::File::FNM_EXTGLOB)
-          else
-            File.fnmatch(@glob, resource.destination_path)
-          end
-        end
-      end
-
       output_resources(resources.to_a)
     end
 
-    Contract OldResourceList => OldResourceList
+    Contract OldResourceList => ArrayOf[Or[Bool, [Pathname, Maybe[::Middleman::Dependencies::Dependency]]]]
     def output_resources(resources)
       res_count = resources.count
 
@@ -156,16 +186,19 @@ module Middleman
                     resources[r].map!(&method(:output_resource))
                   end
 
-                  outputs.flatten!
+                  outputs.flatten!(1)
                   outputs
                 else
                   resources.map(&method(:output_resource))
                 end
 
-      @has_error = true if results.any? { |r| r == false }
+      without_errors = results.reject { |r| r == false }
+
+      @has_error = results.size > without_errors.size
 
       if @cleaning && !@has_error
-        results.each do |p|
+        results.each do |r|
+          p = r[0]
           next unless p.exist?
 
           # handle UTF-8-MAC filename on MacOS
@@ -179,19 +212,21 @@ module Middleman
         end
       end
 
-      resources
+      without_errors
     end
 
     # Figure out the correct event mode.
     # @param [Pathname] output_file The output file path.
     # @param [String] source The source file path.
     # @return [Symbol]
-    Contract Pathname, String => Symbol
-    def which_mode(output_file, source)
+    Contract Pathname, String, Bool => Symbol
+    def which_mode(output_file, source, binary)
       if !output_file.exist?
         :created
+      elsif FileUtils.compare_file(source.to_s, output_file.to_s)
+        binary ? :skipped : :identical
       else
-        FileUtils.compare_file(source.to_s, output_file.to_s) ? :identical : :updated
+        :updated
       end
     end
 
@@ -216,8 +251,8 @@ module Middleman
     # @param [Pathname] output_file The path to output to.
     # @param [String|Pathname] source The source path or contents.
     # @return [void]
-    Contract Pathname, Or[String, Pathname] => Any
-    def export_file!(output_file, source)
+    Contract Pathname, Or[String, Pathname], Maybe[Bool] => Any
+    def export_file!(output_file, source, binary = false)
       ::Middleman::Util.instrument 'write_file', output_file: output_file do
         source = write_tempfile(output_file, source.to_s) if source.is_a? String
 
@@ -227,9 +262,9 @@ module Middleman
                                 [::FileUtils.method(:cp), source.to_s]
                               end
 
-        mode = which_mode(output_file, source_path)
+        mode = which_mode(output_file, source_path, binary)
 
-        if %i[created updated].include? mode
+        if mode == :created
           ::FileUtils.mkdir_p(output_file.dirname)
           method.call(source_path, output_file.to_s)
         end
@@ -243,23 +278,57 @@ module Middleman
     # Try to output a resource and capture errors.
     # @param [Middleman::Sitemap::Resource] resource The resource.
     # @return [void]
-    Contract IsA['Middleman::Sitemap::Resource'] => Or[Pathname, Bool]
+    Contract IsA['Middleman::Sitemap::Resource'] => Or[Bool, [Pathname, Maybe[::Middleman::Dependencies::Dependency]]]
     def output_resource(resource)
       ::Middleman::Util.instrument 'builder.output.resource', path: File.basename(resource.destination_path) do
-        output_file = @build_dir + resource.destination_path.gsub('%20', ' ')
-
         begin
+          output_file = @build_dir + resource.destination_path.gsub('%20', ' ')
+
+          if @track_dependencies && (@only_changed || @missing_and_changed)
+            path = resource.file_descriptor[:full_path].to_s
+
+            if @only_changed && !@invalidated_files.include?(path)
+              trigger(:skipped, output_file)
+              return [output_file, nil]
+            elsif @missing_and_changed && File.exist?(output_file) && !@invalidated_files.include?(path)
+              trigger(:skipped, output_file)
+              return [output_file, nil]
+            end
+          elsif @glob
+            did_match = if defined?(::File::FNM_EXTGLOB)
+                          File.fnmatch(@glob, resource.destination_path, ::File::FNM_EXTGLOB)
+                        else
+                          File.fnmatch(@glob, resource.destination_path)
+                        end
+
+            unless did_match
+              trigger(:skipped, output_file)
+              return [output_file, nil]
+            end
+          end
+
+          deps = nil
+
           if resource.binary?
-            export_file!(output_file, resource.file_descriptor[:full_path])
+            export_file!(output_file, resource.file_descriptor[:full_path], true)
           else
-            export_file!(output_file, binary_encode(resource.render({}, {})))
+            content = resource.render({}, {})
+
+            unless resource.dependencies.empty?
+              deps = ::Middleman::Dependencies::Dependency.new(
+                resource.source_file,
+                resource.dependencies
+              )
+            end
+
+            export_file!(output_file, binary_encode(content))
           end
         rescue StandardError => e
           trigger(:error, output_file, "#{e}\n#{e.backtrace.join("\n")}")
           return false
         end
 
-        output_file
+        [output_file, deps]
       end
     end
 
diff --git a/middleman-core/lib/middleman-core/dependencies.rb b/middleman-core/lib/middleman-core/dependencies.rb
new file mode 100644
index 00000000..61881a90
--- /dev/null
+++ b/middleman-core/lib/middleman-core/dependencies.rb
@@ -0,0 +1,194 @@
+require 'middleman-core/contracts'
+require 'set'
+require 'pathname'
+require 'yaml'
+
+module Middleman
+  module Dependencies
+    class Dependency
+      include Contracts
+
+      Contract String
+      attr_reader :file
+
+      Contract Maybe[SetOf[String]]
+      attr_accessor :depends_on
+
+      Contract String, Maybe[SetOf[String]] => Any
+      def initialize(file, depends_on = nil)
+        @file = file
+        @depends_on = nil
+        @depends_on = Set.new(depends_on) unless depends_on.nil?
+      end
+
+      Contract String
+      def to_s
+        "#<#{self.class} file=#{@file} depends_on=#{@depends_on}>"
+      end
+    end
+
+    class Graph
+      include Contracts
+
+      Contract HashOf[String, String]
+      attr_reader :hashes
+
+      Contract HashOf[String, SetOf[String]]
+      attr_accessor :dependency_map
+
+      def initialize(hashes = {})
+        @hashes = hashes
+        @dependency_map = {}
+      end
+
+      Contract Dependency => Any
+      def add_dependency(file)
+        @dependency_map[file.file] ||= Set.new
+        @dependency_map[file.file] << file.file
+
+        return if file.depends_on.nil?
+
+        file.depends_on.each do |dep|
+          @dependency_map[dep] ||= Set.new
+          @dependency_map[dep] << dep
+          @dependency_map[dep] << file.file
+        end
+      end
+
+      Contract String => Bool
+      def exists?(file_path)
+        @dependency_map.key?(file_path)
+      end
+
+      Contract SetOf[String]
+      def invalidated
+        invalidated_files = @dependency_map.keys.select do |file|
+          if !@hashes.key?(file)
+            # $stderr.puts "#{file} missing hash"
+            true
+          else
+            # $stderr.puts "#{file} invalid hash"
+            hashes[file] != ::Middleman::Dependencies.hashing_method(file)
+          end
+        end
+
+        invalidated_files.reduce(Set.new) do |sum, file|
+          sum << file
+          sum | @dependency_map[file]
+        end
+      end
+    end
+
+    include Contracts
+
+    module_function
+
+    Contract String => String
+    def hashing_method(file_name)
+      ::Digest::SHA1.file(file_name).hexdigest
+    end
+
+    Contract ArrayOf[String]
+    def ruby_files_paths
+      Dir['**/*.rb', 'Gemfile.lock']
+    end
+
+    Contract IsA['::Middleman::Application'], String => String
+    def relativize(app, file)
+      Pathname(File.expand_path(file)).relative_path_from(app.root_path).to_s
+    end
+
+    Contract IsA['::Middleman::Application'], String => String
+    def fullize(app, file)
+      File.expand_path(file, app.root_path)
+    end
+
+    Contract IsA['::Middleman::Application'], Graph => String
+    def serialize(app, graph)
+      ruby_files = ruby_files_paths.reduce([]) do |sum, file|
+        sum << {
+          file: relativize(app, file),
+          hash: hashing_method(file)
+        }
+      end
+
+      source_files = graph.dependency_map.reduce([]) do |sum, (file, depended_on_by)|
+        sum << {
+          file: relativize(app, file),
+          hash: hashing_method(file),
+          depended_on_by: depended_on_by.delete(file).to_a.sort.map { |p| relativize(app, p) }
+        }
+      end
+
+      ::YAML.dump(
+        ruby_files: ruby_files.sort_by { |d| d[:file] },
+        source_files: source_files.sort_by { |d| d[:file] }
+      )
+    end
+
+    DEFAULT_FILE_PATH = 'deps.yml'.freeze
+
+    Contract IsA['::Middleman::Application'], Graph, Maybe[String] => Any
+    def serialize_and_save(app, graph, file_path = DEFAULT_FILE_PATH)
+      File.open(file_path, 'w') do |file|
+        file.write serialize(app, graph)
+      end
+    end
+
+    Contract String => Graph
+    def deserialize(file_path)
+      ::YAML.load_file(file_path)
+    rescue StandardError, ::Psych::SyntaxError => error
+      warn "YAML Exception parsing dependency graph: #{error.message}"
+    end
+
+    Contract ArrayOf[String]
+    def invalidated_ruby_files(known_files)
+      known_files.reject do |file|
+        file[:hash] == hashing_method(file[:file])
+      end
+    end
+
+    class InvalidDepsYAML < RuntimeError
+    end
+
+    class InvalidatedRubyFiles < RuntimeError
+      attr_reader :invalidated
+
+      def initialize(invalidated)
+        super()
+
+        @invalidated = invalidated
+      end
+    end
+
+    Contract IsA['::Middleman::Application'], Maybe[String] => Graph
+    def load_and_deserialize(app, file_path = DEFAULT_FILE_PATH)
+      return Graph.new unless File.exist?(file_path)
+
+      data = deserialize(file_path)
+
+      ruby_files = data[:ruby_files]
+
+      unless (invalidated = invalidated_ruby_files(ruby_files)).empty?
+        raise InvalidatedRubyFiles, invalidated
+      end
+
+      source_files = data[:source_files]
+
+      hashes = source_files.each_with_object({}) do |row, sum|
+        sum[fullize(app, row[:file])] = row[:hash]
+      end
+
+      graph = Graph.new(hashes)
+
+      graph.dependency_map = source_files.each_with_object({}) do |row, sum|
+        sum[fullize(app, row[:file])] = Set.new((row[:depended_on_by] + [row[:file]]).map { |f| fullize(app, f) })
+      end
+
+      graph
+    rescue StandardError
+      raise InvalidDepsYAML
+    end
+  end
+end
diff --git a/middleman-core/lib/middleman-core/extension.rb b/middleman-core/lib/middleman-core/extension.rb
index 1affa64e..43d98690 100644
--- a/middleman-core/lib/middleman-core/extension.rb
+++ b/middleman-core/lib/middleman-core/extension.rb
@@ -61,8 +61,6 @@ module Middleman
   #
   # There are also some less common hooks that can be listened to from within an extension's `initialize` method:
   #
-  # * `app.before_render {|body, path, locs, template_class| ... }` - Manipulate template sources before they are rendered.
-  # * `app.after_render {|content, path, locs, template_class| ... }` - Manipulate output text after a template has been rendered.
   # * `app.ready { ... }` - Run code once Middleman is ready to serve or build files (after `after_configuration`).
 
   #
diff --git a/middleman-core/lib/middleman-core/extensions/asset_hash.rb b/middleman-core/lib/middleman-core/extensions/asset_hash.rb
index 1becd32e..9b21db7d 100644
--- a/middleman-core/lib/middleman-core/extensions/asset_hash.rb
+++ b/middleman-core/lib/middleman-core/extensions/asset_hash.rb
@@ -1,7 +1,7 @@
 require 'middleman-core/util'
 
 class Middleman::Extensions::AssetHash < ::Middleman::Extension
-  option :sources, %w[.css .htm .html .js .php .xhtml], 'List of extensions that are searched for hashable assets.'
+  option :sources, %w[.css .htm .html .js .json .php .xhtml], 'List of extensions that are searched for hashable assets.'
   option :exts, nil, 'List of extensions that get asset hashes appended to them.'
   option :ignore, [], 'Regexes of filenames to skip adding asset hashes to'
   option :rewrite_ignore, [], 'Regexes of filenames to skip processing for path rewrites'
@@ -54,6 +54,7 @@ class Middleman::Extensions::AssetHash < ::Middleman::Extension
       r.add_filter ::Middleman::InlineURLRewriter.new(:asset_hash,
                                                       app,
                                                       r,
+                                                      create_dependencies: true,
                                                       url_extensions: @set_of_exts,
                                                       ignore: options.ignore,
                                                       proc: method(:rewrite_url))
diff --git a/middleman-core/lib/middleman-core/file_renderer.rb b/middleman-core/lib/middleman-core/file_renderer.rb
index 46e8ae78..a4ace8a3 100644
--- a/middleman-core/lib/middleman-core/file_renderer.rb
+++ b/middleman-core/lib/middleman-core/file_renderer.rb
@@ -1,4 +1,5 @@
 require 'tilt'
+require 'set'
 require 'active_support/core_ext/string/output_safety'
 require 'active_support/core_ext/module/delegation'
 require 'middleman-core/contracts'
@@ -15,11 +16,15 @@ module Middleman
       @_cache ||= ::Tilt::Cache.new
     end
 
+    Contract Maybe[SetOf[String]]
+    attr_reader :dependencies
+
     def_delegator :"self.class", :cache
 
     def initialize(app, path)
       @app = app
       @path = path.to_s
+      @dependencies = nil
     end
 
     # Render an on-disk file. Used for everything, including layouts.
@@ -60,28 +65,19 @@ module Middleman
       # Overwrite with frontmatter options
       options = options.deep_merge(options[:renderer_options]) if options[:renderer_options]
 
-      template_class = ::Middleman::Util.tilt_class(path)
-
-      # Allow hooks to manipulate the template before render
-      body = @app.callbacks_for(:before_render).reduce(body) do |sum, callback|
-        callback.call(sum, path, locs, template_class) || sum
-      end
-
       # Read compiled template from disk or cache
       template = ::Tilt.new(path, 1, options) { body }
       # template = cache.fetch(:compiled_template, extension, options, body) do
       #   ::Tilt.new(path, 1, options) { body }
       # end
 
-      # Render using Tilt
-      # content = ::Middleman::Util.instrument 'render.tilt', path: path do
-      #   template.render(context, locs, &block)
-      # end
-      content = template.render(context, locs, &block)
+      @dependencies = nil
 
-      # Allow hooks to manipulate the result after render
-      content = @app.callbacks_for(:after_render).reduce(content) do |sum, callback|
-        callback.call(sum, path, locs, template_class) || sum
+      # Render using Tilt
+      content = ::Middleman::Util.instrument 'render.tilt', path: path do
+        template.render(context, locs, &block).tap do
+          @dependencies = template.dependencies if template.respond_to?(:dependencies)
+        end
       end
 
       output = ::ActiveSupport::SafeBuffer.new ''
diff --git a/middleman-core/lib/middleman-core/filter.rb b/middleman-core/lib/middleman-core/filter.rb
index aa08d2e4..99b91316 100644
--- a/middleman-core/lib/middleman-core/filter.rb
+++ b/middleman-core/lib/middleman-core/filter.rb
@@ -45,9 +45,10 @@ module Middleman
       @callable = callable
     end
 
-    Contract String => String
+    Contract String => [String, Maybe[SetOf[String]]]
     def execute_filter(body)
-      @callable.call(body)
+      result = @callable.call(body)
+      result.is_a?(Array) ? result : [result, nil]
     end
   end
 end
diff --git a/middleman-core/lib/middleman-core/inline_url_rewriter.rb b/middleman-core/lib/middleman-core/inline_url_filter.rb
similarity index 55%
rename from middleman-core/lib/middleman-core/inline_url_rewriter.rb
rename to middleman-core/lib/middleman-core/inline_url_filter.rb
index 92206752..2f36d3c5 100644
--- a/middleman-core/lib/middleman-core/inline_url_rewriter.rb
+++ b/middleman-core/lib/middleman-core/inline_url_filter.rb
@@ -14,13 +14,29 @@ module Middleman
       @resource = resource
     end
 
-    Contract String => String
+    Contract String, Pathname => Maybe[IsA['::Middleman::Sitemap::Resource']]
+    def target_resource(asset_path, dirpath)
+      uri = ::Middleman::Util.parse_uri(asset_path)
+      relative_path = !uri.path.start_with?('/')
+
+      full_asset_path = if relative_path
+                          dirpath.join(asset_path).to_s
+                        else
+                          asset_path
+                        end
+
+      @app.sitemap.by_destination_path(full_asset_path) || @app.sitemap.by_path(full_asset_path)
+    end
+
+    Contract String => [String, Maybe[SetOf[String]]]
     def execute_filter(body)
       path = "/#{@resource.destination_path}"
       dirpath = ::Pathname.new(File.dirname(path))
 
-      ::Middleman::Util.instrument 'inline_url_rewriter', path: path do
-        ::Middleman::Util.rewrite_paths(body, path, @options.fetch(:url_extensions), @app) do |asset_path|
+      ::Middleman::Util.instrument 'inline_url_filter', path: path do
+        deps = Set.new
+
+        new_content = ::Middleman::Util.rewrite_paths(body, path, @options.fetch(:url_extensions), @app) do |asset_path|
           uri = ::Middleman::Util.parse_uri(asset_path)
 
           relative_path = uri.host.nil?
@@ -36,10 +52,17 @@ module Middleman
           next if @options.fetch(:ignore).any? { |r| ::Middleman::Util.should_ignore?(r, full_asset_path) }
 
           result = @options.fetch(:proc).call(asset_path, dirpath, path)
-          asset_path = result if result
+
+          if result
+            deps << target_resource(asset_path, dirpath).source_file if @options.fetch(:create_dependencies, false)
+
+            asset_path = result
+          end
 
           asset_path
         end
+
+        [new_content, deps]
       end
     end
   end
diff --git a/middleman-core/lib/middleman-core/renderers/sass.rb b/middleman-core/lib/middleman-core/renderers/sass.rb
index 43ea1f5f..2e5e3325 100644
--- a/middleman-core/lib/middleman-core/renderers/sass.rb
+++ b/middleman-core/lib/middleman-core/renderers/sass.rb
@@ -1,3 +1,4 @@
+require 'set'
 require 'sass'
 
 begin
@@ -74,6 +75,11 @@ module Middleman
           end
         end
 
+        def dependencies
+          files = @engine.dependencies.map(&:filename)
+          files.empty? ? nil : Set.new(files)
+        end
+
         # Change Sass path, for url functions, to the build folder if we're building
         # @return [Hash]
         def sass_options
diff --git a/middleman-core/lib/middleman-core/sitemap/resource.rb b/middleman-core/lib/middleman-core/sitemap/resource.rb
index 3423cf2c..35c2b705 100644
--- a/middleman-core/lib/middleman-core/sitemap/resource.rb
+++ b/middleman-core/lib/middleman-core/sitemap/resource.rb
@@ -4,7 +4,7 @@ require 'middleman-core/file_renderer'
 require 'middleman-core/template_renderer'
 require 'middleman-core/contracts'
 require 'set'
-require 'middleman-core/inline_url_rewriter'
+require 'middleman-core/inline_url_filter'
 
 module Middleman
   # Sitemap namespace
@@ -37,6 +37,9 @@ module Middleman
       Contract Num
       attr_reader :priority
 
+      Contract Maybe[SetOf[String]]
+      attr_reader :dependencies
+
       # Initialize resource with parent store and URL
       # @param [Middleman::Sitemap::Store] store
       # @param [String] path
@@ -49,6 +52,7 @@ module Middleman
         @ignored  = false
         @filters  = ::Hamster::SortedSet.empty
         @priority = priority
+        @dependencies = Set.new
 
         source = Pathname(source) if source&.is_a?(String)
 
@@ -169,6 +173,8 @@ module Middleman
       # @return [String]
       Contract Hash, Hash, Maybe[Proc] => String
       def render(options_hash = ::Middleman::EMPTY_HASH, locs = ::Middleman::EMPTY_HASH, &_block)
+        @dependencies = Set.new
+
         body = render_without_filters(options_hash, locs)
 
         return body if @filters.empty?
@@ -177,7 +183,9 @@ module Middleman
           if block_given? && !yield(filter)
             output
           elsif filter.is_a?(Filter)
-            filter.execute_filter(output)
+            result = filter.execute_filter(output)
+            @dependencies |= result[1] unless result[1].nil?
+            result[0]
           else
             output
           end
@@ -208,7 +216,9 @@ module Middleman
         locs[:current_path] ||= destination_path
 
         renderer = ::Middleman::TemplateRenderer.new(@app, file_descriptor[:full_path].to_s)
-        renderer.render(locs, opts).to_str
+        renderer.render(locs, opts).to_str.tap do
+          @dependencies |= renderer.dependencies unless renderer.dependencies.nil?
+        end
       end
 
       # A path without the directory index - so foo/index.html becomes
diff --git a/middleman-core/lib/middleman-core/template_context.rb b/middleman-core/lib/middleman-core/template_context.rb
index 7dc9ec1e..de1d62eb 100644
--- a/middleman-core/lib/middleman-core/template_context.rb
+++ b/middleman-core/lib/middleman-core/template_context.rb
@@ -22,6 +22,9 @@ module Middleman
     # Required for Padrino's rendering
     attr_accessor :current_engine
 
+    Contract Maybe[SetOf[String]]
+    attr_reader :dependencies
+
     # Shorthand references to global values on the app instance.
     def_delegators :@app, :config, :logger, :sitemap, :server?, :build?, :environment?, :environment, :data, :extensions, :root, :development?, :production?
 
@@ -34,6 +37,8 @@ module Middleman
       @app = app
       @locs = locs
       @opts = options_hash
+
+      @dependencies = Set.new
     end
 
     # Return the current buffer to the caller and clear the value internally.
@@ -86,6 +91,8 @@ module Middleman
         restore_buffer(buf_was)
       end
 
+      @dependencies << layout_file[:full_path].to_s
+
       # Render the layout, with the contents of the block inside.
       concat_safe_content render_file(layout_file, @locs, @opts) { content }
     ensure
@@ -111,14 +118,18 @@ module Middleman
       source_path = sitemap.file_to_path(partial_file)
       r = sitemap.by_path(source_path)
 
-      if (r && !r.template?) || (Tilt[partial_file[:full_path]].nil? && partial_file[:full_path].exist?)
-        partial_file.read
-      else
-        opts = options_hash.dup
-        locs = opts.delete(:locals)
+      @dependencies << partial_file[:full_path].to_s
 
-        render_file(partial_file, locs, opts, &block)
-      end
+      result = if (r && !r.template?) || (Tilt[partial_file[:full_path]].nil? && partial_file[:full_path].exist?)
+                 partial_file.read
+               else
+                 opts = options_hash.dup
+                 locs = opts.delete(:locals)
+
+                 render_file(partial_file, locs, opts, &block)
+               end
+
+      result
     end
 
     # Locate a partial relative to the current path or the source dir, given a partial's path.
@@ -207,6 +218,7 @@ module Middleman
 
           content_renderer = ::Middleman::FileRenderer.new(@app, path)
           content = content_renderer.render(locs, opts, context, &block)
+          @dependencies |= content_renderer.dependencies unless content_renderer.dependencies.nil?
 
           path = File.basename(path, File.extname(path))
         rescue LocalJumpError
diff --git a/middleman-core/lib/middleman-core/template_renderer.rb b/middleman-core/lib/middleman-core/template_renderer.rb
index 7551022b..0829a360 100644
--- a/middleman-core/lib/middleman-core/template_renderer.rb
+++ b/middleman-core/lib/middleman-core/template_renderer.rb
@@ -1,4 +1,5 @@
 require 'tilt'
+require 'set'
 require 'active_support/core_ext/string/output_safety'
 require 'middleman-core/template_context'
 require 'middleman-core/file_renderer'
@@ -98,9 +99,13 @@ module Middleman
     # Custom error class for handling
     class TemplateNotFound < RuntimeError; end
 
+    Contract Maybe[SetOf[String]]
+    attr_reader :dependencies
+
     def initialize(app, path)
       @app = app
       @path = path
+      @dependencies = nil
     end
 
     # Render a template, with layout, given a path
@@ -167,13 +172,19 @@ module Middleman
                     layout_renderer = ::Middleman::FileRenderer.new(@app, layout_file[:relative_path].to_s)
 
                     ::Middleman::Util.instrument 'builder.output.resource.render-layout', path: File.basename(layout_file[:relative_path].to_s) do
-                      layout_renderer.render(locals, options, context) { content }
+                      layout_renderer.render(locals, options, context) { content }.tap do
+                        @dependencies << layout_file[:full_path].to_s
+                        @dependencies |= layout_renderer.dependencies unless layout_renderer.dependencies.nil?
+                      end
                     end
                   else
                     content
                   end
       end
 
+      @dependencies |= context.dependencies unless context.dependencies.nil?
+      @dependencies = @dependencies.empty? ? nil : @dependencies
+
       # Return result
       content
     ensure
@@ -189,12 +200,15 @@ module Middleman
       # handles cases like `style.css.sass.erb`
       content = nil
 
+      @dependencies = Set.new
+
       while ::Middleman::Util.tilt_class(path)
         begin
           opts[:template_body] = content if content
 
           content_renderer = ::Middleman::FileRenderer.new(@app, path)
           content = content_renderer.render(locs, opts, context, &block)
+          @dependencies |= content_renderer.dependencies unless content_renderer.dependencies.nil?
 
           path = path.sub(/\.[^.]*\z/, '')
         rescue LocalJumpError
diff --git a/middleman-core/lib/middleman-core/version.rb b/middleman-core/lib/middleman-core/version.rb
index f03f26a8..dc0b4402 100644
--- a/middleman-core/lib/middleman-core/version.rb
+++ b/middleman-core/lib/middleman-core/version.rb
@@ -1,5 +1,5 @@
 module Middleman
   # Current Version
   # @return [String]
-  VERSION = '4.3.0.rc.4'.freeze unless const_defined?(:VERSION)
+  VERSION = '5.0.0.rc.1'.freeze unless const_defined?(:VERSION)
 end
diff --git a/vendor.yml b/vendor.yml
deleted file mode 100644
index eec4cafe..00000000
--- a/vendor.yml
+++ /dev/null
@@ -1,3 +0,0 @@
-- fixtures
-- templates
-- vendored-middleman-deps