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?

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 😅

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

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:

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...

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...

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.

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

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.

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

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.

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...

Experiments showed +5%, +3%, +7% wins, but do they really add up to +15%? Likely not, as Airbnb found naive sums can overstate impact by 2x. GrowthBook now offers ✨ Holdouts ✨ for accurate metric measurement:

Another big week for the experimentation industry: OpenAI has acquired Statsig for 1.1B. Graham shares his thoughts on the acquisition and our new Statsig to GrowthBook migration kit: www.linkedin.com/posts/graham...

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?...

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

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 👇

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.

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.

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

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

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?

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.

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.

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 is now live on @vercel Marketplace!

Like an erstwhile PSA: "Do you know where your feature flags are?" As part of our 4.0 launch, we shipped feature flag usage analytics, which means that for every feature flag, you now know: 🛎️ How often it's been evaluated 💁 Which values are being served 📏 Which rules are being hit 🌈 And more

Welcome Home! Our homepage just got a major overhaul 💅 Get instant access to recent experiments and features, see what needs attention, and more. In our latest video, Guy gives Ryan a guided tour of all that's new: www.youtube.com/watch?v=tLjr...

GrowthBook + #MCP gets your A/B test into production in ~60 seconds, all with fewer characters than in this post. See the proof yourself in the video.

After months of engineering work, GrowthBook 4.0 is here with 14+ major features that push the boundaries of what's possible in experimentation platforms.

One size doesn't fit all in experimentation Classic A/B tests → Learning from 2-3 options Safe Rollouts → Shipping without breaking things Bandits → Picking winners from many variations Different tools for different goals. Learn more 👇 blog.growthbook.io/flavors-of-e...

me: "let me just check one quick thing in our data" also me: opens BI tool, waits for it to load, gets distracted, ends up reading AITAH posts We built SQL Explorer in GrowthBook so you can scratch that data itch without the context-switching rabbit hole 🐰

What if experimentation platforms came to YOU instead of the other way around? Try GrowthBook's MCP server and experience the weirdness of conversational experimentation yourself. blog.growthbook.io/experiment-w...

🚀 Launch Month Week 4 drops! New Managed Warehouse = goodbye to 40+ step data setups, hello to one-click deployment and real-time insights ⚡ Plus Feature Usage Analytics to track your flags in real-time and catch tech debt before it catches you 📊 First 2M events free for Pro users! #FeatureFlags

How many do you believe in?

Have you run into this annoyance? You're in your experimentation tool but you have to jump into Looker or Mode just to write some quick SQL to answer a simple data question. All of that context switching adds up, which is why we built SQL Explorer right into GrowthBook #abtesting #datascience

Hot take: The most underrated developer skill in 2025 isn't AI prompting or the latest framework. It's the ability to ship code you're not 100% confident in. Feature flags teach you to embrace uncertainty and let data decide. This mindset shift is worth more than any bootcamp.

Check on your experiments from anywhere with our MCP server. Perfect for those moments when you're having a sandwich but also really want to know how cart-upsell-03 is doing 🥪 🛒

Every experiment teaches you something valuable. But only if you can find and apply those learnings later. We just launched a searchable database of experiment outcomes and insights to make this easier. Now you can find out what your experiments have been trying to tell you.

Your experiment data has been trying to tell you something 📢 Which metrics move easily? Which require heavy lifting? How do your key metrics correlate? New Insights section surfaces all these patterns automatically. docs.growthbook.io/insights

PSA: Your experiment history is probably your most underutilized asset 💎 But only if you can surface those learnings systematically. #experimentation #datascience

You're running dozens, hundreds, thousands!!! of experiments. But are you learning from all of them? Our new Insights section solves this with 5 purpose-built dashboards that turn your experiment history into actionable ... insights.

Week 2 of Launch Month: Insights. Turn your experiment history into strategic advantage with 5 new dashboards: → Executive reporting → Searchable learnings → Timeline visualization → Metric effect analysis → Correlation discovery The more you test, the smarter it gets.

That's a wrap, #snowflakesummit! We had a blast chatting with everyone about how our open source experimentation platform integrates seamlessly with Snowflake to accelerate A/B testing workflows. If you didn't get a chance to talk to us, drop a DM—we'd love to continue the conversation

New shirts just dropped, #snowflakesummit! Swing by for the vibes.

Hey #snowflakesummit ❄️ swing by our booth and get a T-shirt

GrowthBook Launch Month. Week 1. That's right, we have so many exciting things to launch, we had to make it a full month. Click through for even safer rollouts, search filters, #MCP, and our experiment decision framework:

#snowflakesummit starts today ❄️ Stop by our booth to chat about how you can start getting A/B Testing insights from your data.

www.growthbook.io/customers/dr... Dropbox had a problem we've all seen: 6 different experimentation systems. Spoiler: Sometimes the smartest engineering decision is recognizing when someone else has already solved your problem well. What's your team's biggest experimentation pain point?