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testcritic

Unleash vs Optimizely

Feature checklists rarely decide anything. What decides it is the pricing metric, who has to write the tests, and which limitation you can live with.

Entry price

From $75 per seat/month (Pay-As-You-Go, 5-seat minimum self-hosted)

Free tier

Quote on request

Quote only

What drives the bill

The metric that actually scales your invoice.

Self-hosted open source is genuinely free within its project and environment caps. Pay-As-You-Go includes 53M API requests a month with $5 per additional million; Enterprise is an annual custom contract adding SSO, audit and change requests.

Enterprise annual contracts, commonly in the tens of thousands and up. Priced by traffic and modules.

Free tier

Open-source edition is free and self-hosted with no seat limit, but capped at 1 project, 2 environments and 5,000 flags.

No free tier.

Open source

Apache-2.0 (core)

Self-hostable

No-code authoring

Languages

JavaScriptTypeScriptJavaPythonGoC#RubyPHP
JavaScriptPythonJavaC#GoRubyPHPCodeless

Platforms

WebAPIiOSAndroid
WebAPIiOSAndroid

Fits teams

StartupScale-up / mid-marketEnterprise
Enterprise

Adoption

Widely used

Unleash / Bricks Software · since 2014

Widely used

Optimizely · since 2010

Strengths

  • Local evaluation means no user data leaves your infrastructure — a strong GDPR position.
  • Mature, well-documented open-source core with no artificial crippling.
  • Kubernetes and Terraform support for infrastructure-as-code workflows.
  • The most capable visual editor for non-technical experiment authoring.
  • Deep personalisation and audience-targeting features.
  • Established statistics with sequential testing, so peeking is handled correctly.

Limitations

  • Experimentation and analytics are thin; it is a flag system first.
  • Self-hosting means you own uptime for something in your request path.
  • Smaller ecosystem than LaunchDarkly.
  • Expensive, with a suite-oriented sales motion that pushes adjacent products.
  • Client-side testing causes flicker and is increasingly blocked by browsers and blockers.
  • Heavyweight for teams that only need a handful of experiments.

Best for

Privacy-sensitive or cost-sensitive teams that want flags without sending user data to a vendor.

Large marketing organisations running continuous experimentation on high-traffic sites.

All of these integrate with: Slack.

Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.