diff --git a/CHANGELOG.md b/CHANGELOG.md
index 72a8ebf..0a9e956 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.5.0] - 2022-01-21
+
+### Added
+
+- `BLINKA_APPEND` allows multiple test-runs to be appended to the same JSON-file.
+
 ## [0.4.0] - 2021-03-27
 
 ### Changed
diff --git a/README.md b/README.md
index 56dd463..d8f2ff9 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,5 @@
 # Blinka reporter
 
-- [What does this gem do?](#what-does-this-gem-do)
-- [How do I install the gem?](#how-do-i-install-the-gem)
-- [Which ruby testing frameworks are supported?](#which-ruby-testing-frameworks-are-supported)
-- [What is Blinka?](#what-is-blinka)
-- [How to send report to Blinka?](#how-to-send-report-to-blinka)
-- [How can I report tests in TAP-format?](#how-can-i-report-tests-in-tap-format)
-
 ## What does this gem do?
 
 It connects to [supported ruby testing frameworks](#which-ruby-testing-frameworks-are-supported) and outputs a report of all passing, failing and skipped tests into a json-format. This format can be used to report test results using the [ruby client](#how-to-send-report-to-blinka) to [Blinka](#what-is-blinka).
@@ -22,7 +15,7 @@ gem install blinka-reporter
 or add to your Gemfile
 
 ```ruby
-gem 'blinka-repoter', '~> 0.3.1'
+gem 'blinka-repoter', '~> 0.5.0'
 ```
 
 ## Which ruby testing frameworks are supported?
@@ -62,6 +55,30 @@ Add a step to your Github Action Workflow after running tests:
 
 `BLINKA_TAG` is optional and can be used to separate different reports, for example when using a build matrix.
 
+## How to make multiple test runs into one report?
+
+For example when running tests in parallel you might need to run system tests separately.
+By using `BLINKA_JSON` first and the `BLINKA_REPORT` with `BLINKA_APPEND` it will keep the results from both runs:
+
+```yaml
+- name: System tests
+  env:
+    BLINKA_COMMIT: ${{ github.event.pull_request.head.sha || github.sha }}
+    BLINKA_JSON: true
+    BLINKA_REPOSITORY: davidwessman/blinka_reporter
+    BLINKA_TAG: ""
+    PARALLEL_WORKERS: 1
+  run: bundle exec rails test:system
+- name: Tests
+  env:
+    BLINKA_COMMIT: ${{ github.event.pull_request.head.sha || github.sha }}
+    BLINKA_REPORT: true
+    BLINKA_APPEND: true
+    BLINKA_REPOSITORY: davidwessman/blinka_reporter
+    BLINKA_TAG: ""
+  run: bundle exec rails test
+```
+
 ## How can I report tests in TAP-format?
 
 TAP-format ([Test anything protocol](https://testanything.org)) is used to parse tests results on for example Heroku CI.
diff --git a/lib/blinka_reporter/version.rb b/lib/blinka_reporter/version.rb
index 26062e1..bd0661e 100644
--- a/lib/blinka_reporter/version.rb
+++ b/lib/blinka_reporter/version.rb
@@ -1,3 +1,3 @@
 module BlinkaReporter
-  VERSION = '0.4.0'.freeze
+  VERSION = '0.5.0'.freeze
 end
diff --git a/lib/minitest/blinka_plugin.rb b/lib/minitest/blinka_plugin.rb
index bf048c8..6ea0bcd 100644
--- a/lib/minitest/blinka_plugin.rb
+++ b/lib/minitest/blinka_plugin.rb
@@ -11,6 +11,7 @@ def self.plugin_blinka_init(options)
   def plugin_blinka_options(opts, options); end
 
   module BlinkaPlugin
+    REPORT_PATH = 'blinka_results.json'.freeze
     TAP_COMMENT_PAD = 8
     class Reporter < Minitest::StatisticsReporter
       attr_accessor :tests
@@ -29,7 +30,9 @@ def report
         super
 
         tap_report if ENV['BLINKA_TAP']
-        json_report if ENV['BLINKA_JSON'] || ENV['BLINKA_REPORT']
+        if ENV['BLINKA_JSON'] || ENV['BLINKA_REPORT']
+          json_report(append: !ENV['BLINKA_APPEND'].nil?)
+        end
         BlinkaClient.new.report if ENV['BLINKA_REPORT']
       rescue BlinkaClient::BlinkaError => error
         puts(error)
@@ -37,7 +40,7 @@ def report
 
       private
 
-      def json_report
+      def json_report(append:)
         result = {
           total_time: total_time,
           nbr_tests: count,
@@ -48,12 +51,14 @@ def json_report
           results:
             tests.map { |test_result| BlinkaMinitest.new(test_result).report }
         }
+        result = append_previous(result) if append
 
-        File.open('blinka_results.json', 'w+') do |file|
+        File.open(REPORT_PATH, 'w+') do |file|
           file.write(JSON.pretty_generate(result))
         end
+
         puts
-        puts('Test results written to `./blinka_results.json`')
+        puts("Test results written to `#{REPORT_PATH}`")
       end
 
       # Based on https://github.com/kern/minitest-reporters/blob/master/lib/minitest/reporters/progress_reporter.rb
@@ -95,6 +100,26 @@ def find_commit
           )
         )
       end
+
+      private
+
+      def parse_report
+        return unless File.exist?(REPORT_PATH)
+        JSON.parse(File.read(REPORT_PATH))
+      end
+
+      def append_previous(result)
+        previous = parse_report
+        return if previous.nil?
+        return if result[:commit] != previous['commit']
+        return if result[:tag] != previous['tag']
+
+        result[:total_time] += previous['total_time'] || 0
+        result[:nbr_tests] += previous['nbr_tests'] || 0
+        result[:nbr_assertions] += previous['nbr_assertions'] || 0
+        result[:results] += previous['results'] || []
+        result
+      end
     end
   end
 end