iiinova — where your digital self keeps evolving

The best part? It's all open source, warehouse-native, and transparent - you can audit exactly how we calculate everything. Want to see the implementation details? Check out our deep dive: blog.growthbook.io/holdouts-dee...

Most holdouts measure only shipped features. Ours measure everything—including failed experiments. This technical deep dive reveals why we chose reality over clean rooms, and how we built it.

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We built this because our community of 5,000+ engineers kept asking for better ways to prove impact. One customer told us: "Holdouts helped us discover our 'successful' feature was actually causing a 2% revenue decline after 30 days."

Most holdouts measure only shipped features. Ours measure everything—including failed experiments. This technical deep dive reveals why we chose reality over clean rooms, and how we built it.

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🪝 Catch delayed effects - Some changes take weeks to show impact ⚖️ Measure cumulative impact - Stack multiple features and still understand individual contribution 🤝 Build trust in your data - Show stakeholders exactly what drove that revenue increase

Most holdouts measure only shipped features. Ours measure everything—including failed experiments. This technical deep dive reveals why we chose reality over clean rooms, and how we built it.

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Think of them as your experiment's control group that persists even after launch. While 95% of users get your shiny new feature, 5% stay in the original experience. This gives you a clean baseline to measure against.

Most holdouts measure only shipped features. Ours measure everything—including failed experiments. This technical deep dive reveals why we chose reality over clean rooms, and how we built it.

Ever wonder if your feature actually moved the needle, or if that metric bump was just seasonal variance? Most teams struggle with this because they can't isolate the real impact of their changes. That's where holdouts come in - and why we just shipped them in GrowthBook. What are holdouts?

Most holdouts measure only shipped features. Ours measure everything—including failed experiments. This technical deep dive reveals why we chose reality over clean rooms, and how we built it.

GrowthBook @growthbook.io · 17/09/2025

Yesterday's comic was, of course, in reference to Twyman's Law. Applicable not only to experiment analysis, but also life. If it looks too good to be true, then it probably is 😅

GrowthBook @growthbook.io · 16/09/2025

This fantastic comic (xkcd 2899) is about which law?

A black-and-white comic strip with two stick figures. The first figure says, "When a metric becomes a target, it ceases to be a good metric." The second figure, wearing a hat, responds, "Sounds bad. Let's offer a bonus to anyone who identifies a metric that has become a target." The comic illustrates Goodhart's Law, which states that when a measure is used as a goal, it will no longer serve as a good measure.

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GrowthBook @growthbook.io · 15/09/2025

The kicker? ChatGPT already drives 10% of new signups for companies like Vercel. This isn't future speculation - it's happening now. Here's our full guide: blog.growthbook.io/guide-to-geo/ Question: Is anyone A/B testing GEO yet? How is it working?

The Definitive Technical Guide to Generative Engine Optimization (2025)

Everything you need to know about Generative Engine Optimization (GEO).

GrowthBook @growthbook.io · 15/09/2025

• There's no page 2 in AI search - you're either in the answer or you're invisible • Statistics boost AI visibility by 33.9% - AI can't create data, so it gravitates toward sources that provide it • Most AI traffic is invisible - it shows up as "Direct" in analytics

The Definitive Technical Guide to Generative Engine Optimization (2025)

Everything you need to know about Generative Engine Optimization (GEO).

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GrowthBook @growthbook.io · 15/09/2025

As a company, we do things companies do: • Run A/B tests (obviously) • SEO • And now, GEO - optimizing for visibility in AI searches like ChatGPT What's GEO (Generative Engine Optimization)? We were wondering that too, so we did some research. Here are 3 surprising findings:

The Definitive Technical Guide to Generative Engine Optimization (2025)

Everything you need to know about Generative Engine Optimization (GEO).

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GrowthBook @growthbook.io · 12/09/2025

This week we've been sharing everything included in our latest 4.1 release, which includes: → 150+ commits → 8 major features (holdouts, dashboards, #AI, Vercel, Pre-computed dimensions, MCP, FerretDB, Sanity) → 0 vendor lock-in Curious? Full release notes: blog.growthbook.io/growthbook-v...

GrowthBook version 4.1 includes Holdouts, Dashboards, AI features, and More!

GrowthBook Version 4.1

GrowthBook @growthbook.io · 11/09/2025

We're just going to go ahead and say it: GrowthBook is the most comprehensive open-source experimentation platform. Now with #FerretDB support. Because open source means ALL the way down. Learn more: docs.growthbook.io/self-host/fe...

docs.growthbook.io

FerretDB | GrowthBook Docs

How to use FerretDB with GrowthBook

GrowthBook @growthbook.io · 11/09/2025

Sanity offers a powerful content management solution that effortlessly integrates with GrowthBook, enabling you to conduct experiments directly from your content editor without altering any code. This approach allows you to benefit from feature-flag experiments seamlessly.

youtube.com

A/B Testing Made Easy: Sanity + GrowthBook + Next.js Tutorial

Stop hardcoding A/B tests! Learn how to build a professional experimentation system where your content team can create and manage A/B tests directly with Sanity, while GrowthBook handles the…

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GrowthBook for Vercel – Vercel

If you're building on Vercel and NOT running experiments... what are you even doing? 😅 🔗 Install from Vercel Marketplace: vercel.com/marketplace/... #Vercel #NextJS #WebPerformance #EdgeComputing

vercel.com

Open source experimentation and feature flag management.

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GrowthBook for Vercel – Vercel

The technical details you care about: → SDK size: <15KB gzipped → Evaluation time: <1ms at edge → Zero cold starts → Works with App Router, Pages Router, and Edge Runtime Plus, your feature flags now live where your code deploys. No more environment mismatches.

vercel.com

Open source experimentation and feature flag management.

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GrowthBook for Vercel – Vercel

GrowthBook is now native on Vercel Marketplace 🎯 What this means for your Next.js apps: → One-click installation → Unified billing (one less vendor to manage) → Edge-ready performance (we're talking microseconds) → Feature flags that actually work at the edge

vercel.com

Open source experimentation and feature flag management.

GrowthBook @growthbook.io · 09/09/2025

We've introduced practical AI features in GrowthBook 4.1: 🤖 Auto-summarize experiment results 📊 Generate SQL queries from natural language 💡 Enhance experiment hypotheses with AI 🔍 Automatically find similar past experiments ➕ Customize prompts for your org 🙅 Prefer no AI? Disable it entirely.

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Your PM: "What happened with that experiment?" You: Opens 17 tabs, 3 spreadsheets, and a Slack thread Sound familiar? We fixed that. Introducing Experiment Dashboards in GrowthBook 4.1: ✅ Create custom views ✅ Highlight metrics ✅ Add context ✅ Share a single link instead of a dissertation

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GrowthBook @growthbook.io · 09/09/2025

The issue with A/B tests? They conclude. But what about tracking the combined effect of 50 updates over six months? Enter Holdouts: the perpetual experiment. Keep 5% of users on the initial experience, while others enjoy new features. Gauge the true long-term impact of your product changes.

Holdouts in GrowthBook: The Gold Standard for Measuring Cumulative Impact

Many teams ship features weekly but struggle to measure their true cumulative impact. Holdouts in GrowthBook provide a simple way to maintain a control group across multiple features, answering the…

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GrowthBook @growthbook.io · 04/09/2025

Most holdouts measure only shipped features. Ours measure everything—including failed experiments. Because that's what your users actually experienced. Technical breakdown → blog.growthbook.io/holdouts-dee...

Most holdouts measure only shipped features. Ours measure everything—including failed experiments. This technical deep dive reveals why we chose reality over clean rooms, and how we built it.

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GrowthBook @growthbook.io · 27/08/2025

It's possible to build beautiful sites with Framer. But how do you know if they actually convert? You don't unless you test! Our official plugin for Framer lets you do enterprise-level experimentation on your components. Our tutorial helps you get set up in minutes. youtu.be/XqHDLbYCfTM?...

youtu.be

Add Pro A/B Testing to Framer in Minutes (GrowthBook Plugin)

Stop guessing what converts. Start knowing. In this tutorial, I show you how to add enterprise-level A/B testing to your #framer site in minutes using the GrowthBook plugin. No coding required,…

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GrowthBook @growthbook.io · 22/08/2025

It's a hard truth—but we're not all SQL geniuses. Get a little (or lot of help) with your next query by using our new natural language to SQL generation feature. Ask, for example, to list the top 10 pages by view count in the past 3 months and get back a crisp SELECT statement. See Graham's demo

GrowthBook @growthbook.io · 21/08/2025

Teams often struggle with an ever-growing list of metrics, ballooning from 20 to 200. Finding a specific metric during a new experiment can be tough, leading to even more creation ☠️. AI can automatically summarize metrics, making them easier to find and preventing duplicates. Watch Graham's demo 👇

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GrowthBook @growthbook.io · 19/08/2025

Hypothesis enforcement just dropped ✨ No, you won't get a ticket for sloppy hypotheses—but this AI-powered feature ensures your team writes them right. YOU set the quality bar. Academic rigor or lighter touch, your choice. Don't just run experiments, run them right.

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GrowthBook @growthbook.io · 19/08/2025

Automatic experiment result summary generation is here 🪄 Get a summary of your experiment results instantly, including key findings based on your metrics and variants, that's totally customizable to your organization's style and requirements.

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GrowthBook @growthbook.io · 18/08/2025

Here's the tutorial you've been looking for: #Sanity + #Next.js + GrowthBook Ryan provides a comprehensive walkthrough of everything you need to know to set up an enterprise-grade experimentation system that everyone on the team can use! youtu.be/tg85K9K_8-g

youtu.be

A/B Testing Made Easy: Sanity + GrowthBook + Next.js Tutorial

Stop hardcoding A/B tests! Learn how to build a professional experimentation system where your content team can create and manage A/B tests directly with Sanity, while GrowthBook handles the…

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GrowthBook @growthbook.io · 18/08/2025

Graham and Ryan demo all the new AI-powered features recently released in GrowthBook. The best part? Every AI prompt is fully customizable. Want results in haikus? Different language? Your company's tone of voice? You control it all. youtu.be/jhyGxknbGk0

youtu.be

Introducing GrowthBook AI: 6 New Features for Smarter Experimentation

Discover how GrowthBook is revolutionizing A/B testing and experimentation with powerful AI features! In this demo, GrowthBook CEO Graham and Developer Advocate Ryan showcase the latest AI-powered…

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GrowthBook @growthbook.io · 12/08/2025

New tutorial: Run A/B tests without deploying code 🚀 Connect @sanity_io + GrowthBook + Next.js so content editors can test directly from Sanity Studio. No more eng bottlenecks for headline tests. Guide → docs.growthbook.io/guide/sanity What integration should we build next?

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GrowthBook @growthbook.io · 06/08/2025

In the AI era, you don't have a decade to figure it out. You might not even have a year. The takeaway? Place big bets fast. But use experiments as your hedge—fail small to win big. blog.growthbook.io/building-in-...

Building in the AI Era: Lessons from Past Technological Revolutions

Why bolting AI onto existing products is like adding lightbulbs to steam factories. Lessons from Ford to ChatGPT on truly transformative tech adoption.

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GrowthBook @growthbook.io · 06/08/2025

The velocity of change is changing. 🚗 Ford Model T → 1 million sold: 13 years 🔎 Google → 1 million searches/day: 1 year 📱 iPhone → 1 million units: 74 days 💬 ChatGPT → 1 billion searches/day: <1 year This isn't just acceleration—it's a fundamental shift in how quickly markets transform.

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GrowthBook @growthbook.io · 05/08/2025

The real winners in any technological shift don't just adopt new tools. They reimagine entire systems. Are you adding lightbulbs, or are you building the assembly line of the AI era? blog.growthbook.io/building-in-...

Building in the AI Era: Lessons from Past Technological Revolutions

Why bolting AI onto existing products is like adding lightbulbs to steam factories. Lessons from Ford to ChatGPT on truly transformative tech adoption.

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GrowthBook @growthbook.io · 05/08/2025

He didn't just electrify the old system—he invented the assembly line. Build time for a Model T dropped from 12 hours to 93 minutes. Today, companies adding AI chatbots like those factories adding lightbulbs. It's helpful, sure. But it's not transformative.

Building in the AI Era: Lessons from Past Technological Revolutions

Why bolting AI onto existing products is like adding lightbulbs to steam factories. Lessons from Ford to ChatGPT on truly transformative tech adoption.

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GrowthBook @growthbook.io · 05/08/2025

The AI Revolution Isn't Our First Rodeo 🎢 When electricity arrived in the 1880s, most factories just swapped steam engines for electric motors. Same layout. Same processes. Electric lightbulbs where gas lamps used to be. Then Henry Ford reimagined everything.

Building in the AI Era: Lessons from Past Technological Revolutions

Why bolting AI onto existing products is like adding lightbulbs to steam factories. Lessons from Ford to ChatGPT on truly transformative tech adoption.

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Installation takes 60 seconds. Results are immediate.

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→ Precise targeting: User attributes, location, device type, custom rules → Full visibility: Real-time feature flag analytics and debugging tools Unlike other platforms that treat you like a black box, GrowthBook gives you complete control over your experimentation stack.

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→ Built for devs: Works seamlessly with @vercel/flags SDK and Vercel Toolbar → Advanced statistics: Bayesian, Frequentist, CUPED, Sequential testing built-in

Cut feature flag latency to practically zero when you integrate GrowthBook with @Vercel Edge Config. Here's why it's a game changer for technical teams:

GrowthBook @growthbook.io · 29/07/2025

GrowthBook is now live on @vercel Marketplace!