diff --git a/CHANGELOG.md b/CHANGELOG.md
index c84d381b..f55bc39f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 #### Features
 
+* [#879](https://github.com/ruby-grape/grape-swagger/pull/879): Add support for optional path segments - [@spaceraccoon](https://github.com/spaceraccoon)
 * Your contribution here.
 
 #### Fixes
diff --git a/lib/grape-swagger/doc_methods/path_string.rb b/lib/grape-swagger/doc_methods/path_string.rb
index 1fc02aa1..152de24e 100644
--- a/lib/grape-swagger/doc_methods/path_string.rb
+++ b/lib/grape-swagger/doc_methods/path_string.rb
@@ -4,8 +4,7 @@ module GrapeSwagger
   module DocMethods
     class PathString
       class << self
-        def build(route, options = {})
-          path = route.path.dup
+        def build(route, path, options = {})
           # always removing format
           path.sub!(/\(\.\w+?\)$/, '')
           path.sub!('(.:format)', '')
@@ -29,6 +28,23 @@ def build(route, options = {})
 
           [item, path.start_with?('/') ? path : "/#{path}"]
         end
+
+        def generate_optional_segments(path)
+          # always removing format
+          path.sub!(/\(\.\w+?\)$/, '')
+          path.sub!('(.:format)', '')
+
+          paths = []
+          if path.match(/\(.+\)/)
+            # recurse with included optional segment
+            paths.concat(generate_optional_segments(path.sub(/\([^\)]+\)/, '')))
+            # recurse with excluded optional segment
+            paths.concat(generate_optional_segments(path.sub(/\(/, '').sub(/\)/, '')))
+          else
+            paths << path
+          end
+          paths
+        end
       end
     end
   end
diff --git a/lib/grape-swagger/endpoint.rb b/lib/grape-swagger/endpoint.rb
index 96817317..6220749b 100644
--- a/lib/grape-swagger/endpoint.rb
+++ b/lib/grape-swagger/endpoint.rb
@@ -97,18 +97,17 @@ def path_item(routes, options)
       routes.each do |route|
         next if hidden?(route, options)
 
-        @item, path = GrapeSwagger::DocMethods::PathString.build(route, options)
-        @entity = route.entity || route.options[:success]
-
-        verb, method_object = method_object(route, options, path)
-
-        if @paths.key?(path.to_s)
-          @paths[path.to_s][verb] = method_object
-        else
-          @paths[path.to_s] = { verb => method_object }
+        GrapeSwagger::DocMethods::PathString.generate_optional_segments(route.path.dup).each do |path|
+          @item, path = GrapeSwagger::DocMethods::PathString.build(route, path, options)
+          @entity = route.entity || route.options[:success]
+          verb, method_object = method_object(route, options, path)
+          if @paths.key?(path.to_s)
+            @paths[path.to_s][verb] = method_object
+          else
+            @paths[path.to_s] = { verb => method_object }
+          end
+          GrapeSwagger::DocMethods::Extensions.add(@paths[path.to_s], @definitions, route)
         end
-
-        GrapeSwagger::DocMethods::Extensions.add(@paths[path.to_s], @definitions, route)
       end
     end
 
diff --git a/spec/issues/878_optional_path_segments.rb b/spec/issues/878_optional_path_segments.rb
new file mode 100644
index 00000000..2421f064
--- /dev/null
+++ b/spec/issues/878_optional_path_segments.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe '#878 handle optional path segments' do
+  let(:app) do
+    Class.new(Grape::API) do
+      resource :books do
+        get 'page(/one)(/:two)/three' do
+          { message: 'hello world' }
+        end
+      end
+
+      add_swagger_documentation
+    end
+  end
+  let(:parameters) { subject['paths']['/books/page/{two}/three']['get']['parameters'] }
+
+  subject do
+    get '/swagger_doc'
+    JSON.parse(last_response.body)
+  end
+
+  specify do
+    section_param = parameters.find { |param| param['name'] == 'two' }
+    expect(section_param['in']).to eq 'path'
+    expect subject['paths'].keys.to eq ['/books/page/three', '/books/page/{two}/three', '/books/page/one/three', '/books/page/one/{two}/three']
+  end
+end
diff --git a/spec/lib/path_string_spec.rb b/spec/lib/path_string_spec.rb
index 7380bce4..4706cb78 100644
--- a/spec/lib/path_string_spec.rb
+++ b/spec/lib/path_string_spec.rb
@@ -12,7 +12,7 @@
     specify 'The original route path is not mutated' do
       route = Struct.new(:version, :path).new
       route.path = '/foo/:dynamic/bar'
-      subject.build(route, add_version: true)
+      subject.build(route, route.path.dup, add_version: true)
       expect(route.path).to eq '/foo/:dynamic/bar'
     end
 
@@ -23,17 +23,17 @@
 
         specify 'The returned path includes version' do
           route.path = '/{version}/thing(.json)'
-          expect(subject.build(route, options)).to eql ['Thing', '/v1/thing']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/v1/thing']
           route.path = '/{version}/thing/foo(.json)'
-          expect(subject.build(route, options)).to eql ['Foo', '/v1/thing/foo']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/v1/thing/foo']
           route.path = '/{version}/thing(.:format)'
-          expect(subject.build(route, options)).to eql ['Thing', '/v1/thing']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/v1/thing']
           route.path = '/{version}/thing/foo(.:format)'
-          expect(subject.build(route, options)).to eql ['Foo', '/v1/thing/foo']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/v1/thing/foo']
           route.path = '/{version}/thing/:id'
-          expect(subject.build(route, options)).to eql ['Thing', '/v1/thing/{id}']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/v1/thing/{id}']
           route.path = '/{version}/thing/foo/:id'
-          expect(subject.build(route, options)).to eql ['Foo', '/v1/thing/foo/{id}']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/v1/thing/foo/{id}']
         end
       end
 
@@ -43,17 +43,17 @@
 
         specify 'The returned path does not include version' do
           route.path = '/{version}/thing(.json)'
-          expect(subject.build(route, options)).to eql ['Thing', '/thing']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/thing']
           route.path = '/{version}/thing/foo(.json)'
-          expect(subject.build(route, options)).to eql ['Foo', '/thing/foo']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/thing/foo']
           route.path = '/{version}/thing(.:format)'
-          expect(subject.build(route, options)).to eql ['Thing', '/thing']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/thing']
           route.path = '/{version}/thing/foo(.:format)'
-          expect(subject.build(route, options)).to eql ['Foo', '/thing/foo']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/thing/foo']
           route.path = '/{version}/thing/:id'
-          expect(subject.build(route, options)).to eql ['Thing', '/thing/{id}']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/thing/{id}']
           route.path = '/{version}/thing/foo/:id'
-          expect(subject.build(route, options)).to eql ['Foo', '/thing/foo/{id}']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/thing/foo/{id}']
         end
       end
 
@@ -63,17 +63,17 @@
 
         specify 'The returned path does not include version' do
           route.path = '/{version}/thing(.json)'
-          expect(subject.build(route, options)).to eql ['Thing', '/thing']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/thing']
           route.path = '/{version}/thing/foo(.json)'
-          expect(subject.build(route, options)).to eql ['Foo', '/thing/foo']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/thing/foo']
           route.path = '/{version}/thing(.:format)'
-          expect(subject.build(route, options)).to eql ['Thing', '/thing']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/thing']
           route.path = '/{version}/thing/foo(.:format)'
-          expect(subject.build(route, options)).to eql ['Foo', '/thing/foo']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/thing/foo']
           route.path = '/{version}/thing/:id'
-          expect(subject.build(route, options)).to eql ['Thing', '/thing/{id}']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/thing/{id}']
           route.path = '/{version}/thing/foo/:id'
-          expect(subject.build(route, options)).to eql ['Foo', '/thing/foo/{id}']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/thing/foo/{id}']
         end
       end
 
@@ -83,17 +83,17 @@
 
         specify 'The returned path does not include version' do
           route.path = '/{version}/thing(.json)'
-          expect(subject.build(route, options)).to eql ['Thing', '/thing']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/thing']
           route.path = '/{version}/thing/foo(.json)'
-          expect(subject.build(route, options)).to eql ['Foo', '/thing/foo']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/thing/foo']
           route.path = '/{version}/thing(.:format)'
-          expect(subject.build(route, options)).to eql ['Thing', '/thing']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/thing']
           route.path = '/{version}/thing/foo(.:format)'
-          expect(subject.build(route, options)).to eql ['Foo', '/thing/foo']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/thing/foo']
           route.path = '/{version}/thing/:id'
-          expect(subject.build(route, options)).to eql ['Thing', '/thing/{id}']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Thing', '/thing/{id}']
           route.path = '/{version}/thing/foo/:id'
-          expect(subject.build(route, options)).to eql ['Foo', '/thing/foo/{id}']
+          expect(subject.build(route, route.path.dup, options)).to eql ['Foo', '/thing/foo/{id}']
         end
       end
     end