1"use strict";(self.webpackChunkdocs=self.webpackChunkdocs||[]).push([[4705],{20375:e=>{e.exports=JSON.parse('{"permalink":"/blog/guide-of-ab-test-with-feature-flag","source":"@site/blog/2025/2025-07-16-guide-of-ab-test-with-feature-flag.md","title":"A Practical Guide to A/B Testing with Feature Flags","description":"Improving a website or application inevitably involves releasing new features and changing designs. However, every change carries inherent risks: \\"Will this break something?\\" or \\"Will this negatively impact the user experience?\\"","date":"2025-07-16T12:00:00.000Z","tags":[{"inline":true,"label":"ABtest","permalink":"/blog/tags/a-btest"},{"inline":true,"label":"FeatureFlag","permalink":"/blog/tags/feature-flag"},{"inline":true,"label":"Experiments","permalink":"/blog/tags/experiments"}],"readingTime":4.55,"hasTruncateMarker":true,"authors":[{"name":"Yoshifumi Kakinoki","title":"Software Engineer","url":"https://github.com/kakcy","page":{"permalink":"/blog/authors/yoshifumi-kakinoki"},"socials":{"github":"https://github.com/kakcy"},"imageURL":"/img/members/yoshifumi-kakinoki.png","key":"yoshifumi-kakinoki"}],"frontMatter":{"title":"A Practical Guide to A/B Testing with Feature Flags","slug":"guide-of-ab-test-with-feature-flag","authors":["yoshifumi-kakinoki"],"tags":["ABtest","FeatureFlag","Experiments"],"hide_table_of_contents":false,"date":"2025-07-16T12:00"},"unlisted":false,"prevItem":{"title":"Feature Flags Without Leaving Your IDE","permalink":"/blog/feature-flags-without-leaving-your-ide"},"nextItem":{"title":"Introducing OpenFeature Support for Bucketeer Go SDK","permalink":"/blog/introducing-openfeature-support-for-bucketeer-go-sdk"}}')},28453:(e,n,t)=>{t.d(n,{RP:()=>r,xA:()=>l});var i=t(96540);const s=i.createContext({});function r(e){const n=i.useContext(s);return i.useMemo((()=>"function"==typeof e?e(n):{...n,...e}),[n,e])}const a={};function l({components:e,children:n,disableParentContext:t}){let l;return l=t?"function"==typeof e?e({}):e||a:r(e),i.createElement(s.Provider,{value:l},n)}},31158:(e,n,t)=>{t.r(n),t.d(n,{assets:()=>o,contentTitle:()=>l,default:()=>d,frontMatter:()=>a,metadata:()=>i,toc:()=>c});var i=t(20375),s=t(74848),r=t(28453);const a={title:"A Practical Guide to A/B Testing with Feature Flags",slug:"guide-of-ab-test-with-feature-flag",authors:["yoshifumi-kakinoki"],tags:["ABtest","FeatureFlag","Experiments"],hide_table_of_contents:!1,date:"2025-07-16T12:00"},l=void 0,o={authorsImageUrls:[void 0]},c=[{value:"The Fundamentals of Feature Flags and A/B Testing",id:"the-fundamentals-of-feature-flags-and-ab-testing",level:3},{value:"What Are Feature Flags?",id:"what-are-feature-flags",level:4},{value:"Why Are They So Effective for A/B Testing?",id:"why-are-they-so-effective-for-ab-testing",level:4},{value:"Example 1: Optimizing Marketing Copy with a Simple A/B Test",id:"example-1-optimizing-marketing-copy-with-a-simple-ab-test",level:3},{value:"Steps",id:"steps",level:4},{value:"Example 2: Safely Verifying a High-Risk Feature with an A/B Test",id:"example-2-safely-verifying-a-high-risk-feature-with-an-ab-test",level:3},{value:"Steps",id:"steps-1",level:4},{value:"Conclusion",id:"conclusion",level:3}];function h(e){const n={a:"a",code:"code",h3:"h3",h4:"h4",hr:"hr",li:"li",ol:"ol",p:"p",strong:"strong",ul:"ul",...(0,r.RP)(),...e.components};return(0,s.jsxs)(s.Fragment,{children:[(0,s.jsx)(n.p,{children:'Improving a website or application inevitably involves releasing new features and changing designs. However, every change carries inherent risks: "Will this break something?" or "Will this negatively impact the user experience?"'}),"\n",(0,s.jsxs)(n.p,{children:["This article explains how to use a powerful technique called ",(0,s.jsx)(n.strong,{children:"feature flags"})," to manage these risks and effectively run ",(0,s.jsx)(n.strong,{children:"A/B tests"})," that are both safe and data-driven, complete with practical examples."]}),"\n",(0,s.jsx)(n.h3,{id:"the-fundamentals-of-feature-flags-and-ab-testing",children:"The Fundamentals of Feature Flags and A/B Testing"}),"\n",(0,s.jsx)(n.p,{children:"First, let's quickly review the core concept of feature flags."}),"\n",(0,s.jsx)(n.h4,{id:"what-are-feature-flags",children:"What Are Feature Flags?"}),"\n",(0,s.jsxs)(n.p,{children:["In simple terms, a feature flag acts like an ",(0,s.jsx)(n.strong,{children:"ON/OFF switch for a feature"}),". By embedding these switches in your source code, you can control a feature's availability from an external dashboard without having to redeploy your application."]}),"\n",(0,s.jsx)(n.h4,{id:"why-are-they-so-effective-for-ab-testing",children:"Why Are They So Effective for A/B Testing?"}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"Deploy Now, Release Later"}),": You can deploy new code with the feature flag turned OFF, and then start your A/B test at any time by simply turning the flag ON for a specific set of users."]}),"\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"Risk Mitigation"}),': You can perform a gradual rollout, such as "release to internal users only" or "enable for 1% of users." If any problems arise, you can instantly turn the flag OFF, minimizing the impact.']}),"\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"Rapid, Data-Driven Decisions"}),": Test multiple variations simultaneously and collect real-time data. This allows you to quickly switch to the winning pattern, making decisions based on data, not just intuition."]}),"\n"]}),"\n",(0,s.jsx)(n.hr,{}),"\n",(0,s.jsx)(n.h3,{id:"example-1-optimizing-marketing-copy-with-a-simple-ab-test",children:"Example 1: Optimizing Marketing Copy with a Simple A/B Test"}),"\n",(0,s.jsx)(n.p,{children:"Even a small change in wording can have a significant impact on user behavior. A/B testing is the most reliable way to find the most effective marketing copy."}),"\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Scenario: A/B testing the text on a new campaign banner to see which one gets more clicks."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"Variation A"}),': "Special Offer: Get 20% Off Now!"']}),"\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"Variation B"}),': "Save Big: Your 20% Discount is Waiting!"']}),"\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"Hypothesis"}),": Which phrasing will achieve a higher Click-Through Rate (CTR)?"]}),"\n"]}),"\n",(0,s.jsx)(n.h4,{id:"steps",children:"Steps"}),"\n",(0,s.jsxs)(n.ol,{children:["\n",(0,s.jsxs)(n.li,{children:["\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Create a Feature Flag with Variations."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"\ud83d\udca1"})," Use the ",(0,s.jsx)(n.strong,{children:"Feature Flag"})," to create a flag (e.g., ",(0,s.jsx)(n.code,{children:"campaign-banner-text"}),"). Add two variations, one for each string of text you want to test."]}),"\n"]}),"\n"]}),"\n",(0,s.jsxs)(n.li,{children:["\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Set the Rollout percentage to distribute the variation evenly across all users."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"\ud83d\udca1"})," Set the delivery ratio to 50%."]}),"\n"]}),"\n",(0,s.jsxs)(n.p,{children:["\u270f\ufe0f ",(0,s.jsx)(n.a,{href:"https://docs.bucketeer.io/feature-flags/creating-feature-flags/targeting#rollout-percentage",children:"Rollout Percentage"})]}),"\n"]}),"\n",(0,s.jsxs)(n.li,{children:["\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Set the Goal (KPI)."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"\ud83d\udca1"})," Use the ",(0,s.jsx)(n.strong,{children:"Goal"}),' to define a conversion event, such as a "click campaign event" This allows Bucketeer to track which variation performs better against your business objectives.']}),"\n"]}),"\n",(0,s.jsxs)(n.p,{children:["\u270f\ufe0f ",(0,s.jsx)(n.a,{href:"https://docs.bucketeer.io/feature-flags/testing-with-flags/goals",children:"Goal"})]}),"\n"]}),"\n",(0,s.jsxs)(n.li,{children:["\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Set the Experiments."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"\ud83d\udca1"})," Using the feature flags and goals you created, set up an A/B test using the ",(0,s.jsx)(n.strong,{children:"Experiment"}
1),". Specify the period you want to test and measure the goal results for each flag over a certain period of time."]}),"\n"]}),"\n",(0,s.jsxs)(n.p,{children:["\u270f\ufe0f ",(0,s.jsx)(n.a,{href:"https://docs.bucketeer.io/feature-flags/testing-with-flags/experiments",children:"Experiments"})]}),"\n"]}),"\n",(0,s.jsxs)(n.li,{children:["\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Implement Tracking and Analyze Results."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsx)(n.li,{children:"In your application, you can use the Bucketeer SDK to display campaign link based on the strings retrieved from the FeatureFlags and send them when the goal event occurs."}),"\n"]}),"\n"]}),"\n"]}),"\n",(0,s.jsx)(n.p,{children:"After you've run your test for a sufficient period of time, you can analyze the results in your dashboard to see which wording drives better conversions for your campaign."}),"\n",(0,s.jsx)(n.hr,{}),"\n",(0,s.jsx)(n.h3,{id:"example-2-safely-verifying-a-high-risk-feature-with-an-ab-test",children:"Example 2: Safely Verifying a High-Risk Feature with an A/B Test"}),"\n",(0,s.jsx)(n.p,{children:"Large-scale changes to a service's core functionality are incredibly risky. Feature flags allow you to run an A/B test to verify if the new feature truly improves business metrics, all while managing the risk."}),"\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Scenario: A/B testing a new AI-powered recommendation engine on an e-commerce site."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"Variation A (Control)"}),': The current recommendation logic, based on "Top Popularity Rankings."']}),"\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"Variation B (Test)"}),": A new, personalized recommendation logic powered by AI."]}),"\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"Hypothesis"}),": Variation B will increase the conversion rate (CVR) from recommendations compared to Variation A."]}),"\n"]}),"\n",(0,s.jsx)(n.h4,{id:"steps-1",children:"Steps"}),"\n",(0,s.jsxs)(n.ol,{children:["\n",(0,s.jsxs)(n.li,{children:["\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Prepare the Feature Flag. Design a Safety-First A/B Test."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"\ud83d\udca1"})," Use feature flags to create a flag with a name such as product-recommendation-logic. You can safely perform A/B testing by first enabling it for testers using Targeting and then gradually increasing the number of enabled users using Progressive Rollout."]}),"\n"]}),"\n"]}),"\n",(0,s.jsxs)(n.li,{children:["\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Set the Goal (KPI)."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"\ud83d\udca1"})," Use the ",(0,s.jsx)(n.strong,{children:"Goal"}),' to define a conversion event, such as a "purchase from recommendation." This allows Bucketeer to track which variation performs better against your business objectives.']}),"\n"]}),"\n",(0,s.jsxs)(n.p,{children:["\u270f\ufe0f ",(0,s.jsx)(n.a,{href:"https://docs.bucketeer.io/feature-flags/testing-with-flags/goals",children:"Goal"})]}),"\n"]}),"\n",(0,s.jsxs)(n.li,{children:["\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Set the Experiments."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:[(0,s.jsx)(n.strong,{children:"\ud83d\udca1"})," Using the feature flags and goals you created, set up an A/B test using the ",(0,s.jsx)(n.strong,{children:"Experiment"}),". Specify the period you want to test and measure the goal results for each flag over a certain period of time."]}),"\n"]}),"\n",(0,s.jsxs)(n.p,{children:["\u270f\ufe0f ",(0,s.jsx)(n.a,{href:"https://docs.bucketeer.io/feature-flags/testing-with-flags/experiments",children:"Experiments"})]}),"\n"]}),"\n",(0,s.jsxs)(n.li,{children:["\n",(0,s.jsx)(n.p,{children:(0,s.jsx)(n.strong,{children:"Implement Tracking and Analyze Results."})}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsx)(n.li,{children:"In your application, use the Bucketeer SDK to track when the goal event occurs."}),"\n"]}),"\n"]}),"\n"]}),"\n",(0,s.jsx)(n.p,{children:"You can analyze the results in the dashboard and make data-driven decisions. If the test flag is clearly driving lower conversions, you can immediately turn off the test and end it."}),"\n",(0,s.jsx)(n.hr,{}),"\n",(0,s.jsx)(n.h3,{id:"conclusion",children:"Conclusion"}),"\n",(0,s.jsx)(n.p,{children:"A/B testing with feature flags functions as:"}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:["A ",(0,s.jsx)(n.strong,{children:'"compass"'})," for safely navigating high-risk feature changes."]}),"\n",(0,s.jsxs)(n.li,{children:["A ",(0,s.jsx)(n.strong,{children:'"measuring instrument"'})," for gauging the true ROI of your personalization efforts."]}),"\n"]}),"\n",(0,s.jsx)(n.p,{children:"Instead of relying on intuition or experience alone, you can improve your service based on the objective truth of data. Feature flags are a powerful weapon in your arsenal to achieve just that."})]})}function d(e={}){const{wrapper:n}={...(0,r.RP)(),...e.components};return n?(0,s.jsx)(n,{...e,children:(0,s.jsx)(h,{...e})}):h(e)}}}]);
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