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Decision Guide

Best A/B Testing Tool for Startups

Updated December 2025
10 min read
TL;DR

The short answer: For most startups, ExperimentHQ is the best choice—it's free to start, takes 5 minutes to set up, and doesn't require developers. If you have a technical team and want open-source, use GrowthBook. Avoid enterprise tools like VWO and Optimizely—they're 100x more expensive than you need.

Who this is for

  • Early-stage startups (pre-seed to Series A)
  • Bootstrapped founders watching every dollar
  • Growth teams at small companies
  • Anyone with 1,000-100,000 monthly visitors

Who this is NOT for

  • Enterprise companies with $50K+ budgets (see VWO vs Optimizely)
  • Sites with under 1,000 monthly visitors (you need more traffic first)

What Startups Actually Need

Affordable Pricing

Free tier or under $100/month. Startups can't justify $10,000+/year tools.

Quick Setup

Under 30 minutes to first test. You don't have weeks for implementation.

No-Code Option

Visual editor for non-technical founders. Developers should be building product.

Lightweight

Small script size. Your site is probably already slow enough.

Tool Comparison

ToolPriceSetup TimeDev RequiredVerdict
ExperimentHQFree - $29/mo5 minNoBest Overall
GrowthBookFree (self-hosted)2-4 hoursYesBest Open Source
PostHogFree - $450/mo30 minYesBest with Analytics
StatsigFree - Custom1-2 hoursYesBest for Developers
VWO$10,000+/year1-2 weeksNoOverkill

Our Recommendations

ExperimentHQ

Best for Most Startups

Built for speed and simplicity. Visual editor means non-technical founders can run tests. Free tier includes 5,000 visitors/month.

Why it's great for startups

  • 5-minute setup, no developers needed
  • Free tier for early-stage companies
  • Lightweight script (<5KB)
  • Visual editor for quick changes

Considerations

  • Newer platform (less brand recognition)
  • No server-side SDK yet

GrowthBook

Best Open Source

Open-source and self-hosted. Great if you have engineering resources and want full control. Free forever if you run it yourself.

Pros

  • Completely free (self-hosted)
  • Full data ownership
  • Feature flags included

Cons

  • Requires engineering time to set up
  • No visual editor
  • Self-hosting costs (servers, maintenance)

Best for: Technical startups with engineering resources who want open-source and full control.

PostHog

Best with Analytics

All-in-one product analytics with A/B testing. Great if you're already using PostHog for analytics.

Pros

  • Analytics + A/B testing in one tool
  • Generous free tier
  • Feature flags included

Cons

  • A/B testing is secondary feature
  • No visual editor
  • Gets expensive at scale

Best for: Startups already using PostHog for analytics who want to add experimentation.

When Should You Start A/B Testing?

✓ You're ready if...

  • • You have 1,000+ monthly visitors
  • • You have a clear conversion goal (signups, purchases, etc.)
  • • You have hypotheses to test (not just random ideas)
  • • You can wait 2-4 weeks for results

✗ You're NOT ready if...

  • • You have under 1,000 monthly visitors (focus on growth first)
  • • You're still finding product-market fit (talk to users instead)
  • • You don't have a clear conversion metric
  • • You need results in days, not weeks

💡 Pro tip: If you're pre-PMF, spend your time talking to users and iterating quickly. A/B testing is for optimization, not discovery.

Mistakes Startups Make

❌ Buying enterprise tools too early

VWO and Optimizely cost $10,000-$50,000/year. That's 10-50 months of ExperimentHQ. Don't waste runway on tools you don't need.

❌ Testing with too little traffic

With 500 visitors/month, you'd need 6+ months for a single test. Focus on growth first, then optimize.

❌ Building your own testing tool

"We'll just build it ourselves" costs 10x more in engineering time than paying for a tool. Your engineers should build product.

❌ Testing random ideas

"Let's test a green button vs blue button" wastes time. Start with user research to generate meaningful hypotheses.

Our Recommendation

For most startups, the choice is simple:

Non-technical founder? Use ExperimentHQ. 5-minute setup, visual editor, free tier.

Technical team that wants open-source? Use GrowthBook. Free, self-hosted, full control.

Already using PostHog? Just enable their A/B testing feature.

Frequently Asked Questions

What's the best free A/B testing tool?
ExperimentHQ offers a free tier with 5,000 monthly visitors. For completely free, GrowthBook is open-source but requires self-hosting.
How much should a startup spend on A/B testing?
$0-$100/month is reasonable for most startups. If you're spending more, you're probably overpaying for features you don't need.
Should I build my own A/B testing tool?
No. Building a proper A/B testing tool takes months of engineering time. That's worth $50,000+ in opportunity cost. Just pay $29/month for a tool.

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