Unleash

Feature Flags First, Experimentation as One Use Case

Unleash is not built primarily as an A/B testing tool the way Optimizely, AB Tasty or Kameleoon are; it is a feature flag and progressive-delivery platform where A/B/n testing with flag variants is one of several use cases alongside gradual rollouts, canary releases and kill switches. For a team whose "experiments" are really staged feature rollouts with measurement attached rather than marketing-page optimisation, that is a meaningfully different tool than a visual-editor testing suite, and it belongs in this comparison for exactly that reason.

What It Does

• Unlimited feature flags, projects and environments on every plan, including the free open-source tier
• A/B/n testing with flag variants and user segmentation & stickiness
• Impact metrics, automated progression, and safeguards for rollout monitoring
• Four-eyes approval and change request workflows for flag changes
• 25+ official SDKs, with server-side SDKs evaluating flags locally so no end-user data leaves the customer's own infrastructure
• SOC2 Type II, ISO27001 and FedRAMP-track compliance on hosted Enterprise plans

Genuinely Open Source, Not Source-Available

The core is licensed AGPLv3 (Apache 2.0 for official Docker images and pre-v8 releases), self-hostable on Docker or Kubernetes, with no seat limit -- capped at 1 project, 2 environments and 5,000 feature flags per instance, which is a real ceiling but a workable one for most teams starting out. Thousands of teams reportedly run it in production this way with no bill at all.

Unleash Enterprise Pay-As-You-Go is $75/seat/month, billed monthly with a 14-day free trial and no contract; annual Enterprise is custom-quoted. Client-side monthly active users and flag evaluations are never billed on either tier, which matters for a tool whose whole job is being evaluated constantly in production.

EU or US Hosting -- A Real Choice, Not an EU Default

The pricing page states plainly: "Data residency options in the US or EU. Included [on both Pay-As-You-Go and annual Enterprise]." The published subprocessors page is more specific still: AWS is listed as a subprocessor for "Customer hosted instances. User accounts," located *"EU or US"**, with the footnote: "AWS Region depends on each customer selection. Options: Europe (Frankfurt) or US-East."

That means a European customer who wants EU-only hosting has to select it; it is not the default a customer gets by doing nothing, and two of the three named sub-processors -- Zendesk (support) and LogRocket (session recording, free-trial users only) -- are US-based regardless of which AWS region a customer picks. The Data Processing Agreement is thorough on the legal side of this: EU Commission Standard Contractual Clauses (2021/914/EU) are incorporated by reference for EEA, UK and Swiss transfers, with the relevant Module and Clause options specified rather than left vague.

Norwegian Entity, With a US Sibling for US Customers

Operated by Bricks Software AS, Edvard Storms gate 2, 0166 Oslo, Norway, for any customer located outside the United States. The Terms separately name Bricks Software Inc., 2261 Market Street STE 86259, San Francisco, CA, as the contracting entity for US-located customers -- meaning a European customer's contract is with the Norwegian entity specifically, not the US one. No document reviewed states which entity is the ultimate parent or how the two are related beyond both operating under the Unleash brand, so that structure is disclosed here rather than resolved.

Where It Fits

If the need is a visual page-optimisation editor, AB Tasty, Convert Experiences or Kameleoon fit that job more directly. If the need is flag-driven progressive rollout with experimentation layered on top, and a genuinely free self-hosted option matters, Unleash is the closer Optimizely alternative. See also PostHog for a product-analytics-plus-flags combination, and the wider A/B Testing category.