The best mobile app A/B testing tools must support your actual SDK, identity model, and outcome measurement. Firebase is a natural candidate for teams already using its analytics and Remote Config. Statsig, GrowthBook, PostHog, and LaunchDarkly merit evaluation for broader product experimentation. Amplitude and Optimizely require particular care around the edition and analysis access included in the quote.
This guide is for mobile product leads and engineers comparing experiments inside an app. It uses official documentation and attributed user reviews checked on November 12, 2026, not hands-on benchmarks. Store-listing experiments answer a different question from changes to onboarding, paywalls, or product behavior. See the overall comparison for other testing surfaces and the free tools guide for budget boundaries.
An app version is part of the experiment
Imagine a language-learning app testing a shorter onboarding sequence. The new screens exist only in the latest release, but many active users still have an older version. A person can qualify for the experiment in the dashboard without having code capable of showing the treatment.
That makes version eligibility a procurement requirement. Ask how the platform targets supported versions, how the app behaves when configuration is unavailable, and when the exposure event is recorded. A downloaded configuration, a calculated assignment, and a screen actually shown are different events. Your analysis needs the distinction relevant to the question being tested.
Now add a user who begins anonymously, creates an account, and returns on another device. Decide whether assignment should remain stable and how events will join across that transition. A vendor's claim to support iOS or Android does not settle those design choices.
When I compare app experimentation tools, I first ask for a trace of one user's journey through eligibility, assignment, exposure, and outcome. If the team cannot explain that trace, a polished results chart is premature. The same trace becomes a useful acceptance test during implementation.
Compare the SDK and plan together
The table is a shortlist, not a universal ranking. Public SDK availability establishes a starting point; your specific language, framework version, implementation pattern, and analysis entitlement still need verification.
| Tool | Qualifying plan and cost | Suitable situation | Assessment for this guide | Evidence confidence |
|---|---|---|---|---|
| Firebase | A/B Testing no-cost; Remote Config has daily fetch allowance and overages. Spark within quota; Blaze for paid Remote Config usage. | App team already using Firebase Analytics and Remote Config | partly meets: Native SDK route documented; exact SDK/version, exposure, offline and assignment behavior require a pilot. | Native route documented; end-to-end mobile behavior untested |
| Statsig | Developer $0; Pro $150/project/month including 5M events. Developer for core experiments and visual editor; Pro for holdouts/bandits. | Engineering-supported product team wanting hosted analysis | partly meets: Native SDK route documented; exact SDK/version, exposure, offline and assignment behavior require a pilot. | Native route documented; end-to-end mobile behavior untested |
| GrowthBook | Starter $0; Pro $40/seat/month. Starter for SDK experiments; Pro for visual editor and split URL tests. | Engineering/data team owning its warehouse integration | partly meets: Native SDK route documented; exact SDK/version, exposure, offline and assignment behavior require a pilot. | Native route documented; end-to-end mobile behavior untested |
| PostHog | 1M flag requests/month free; paid rates start at $0.000100/request. Free or pay-as-you-go. | Product team already collecting dependable PostHog events | partly meets: Native SDK route documented; exact SDK/version, exposure, offline and assignment behavior require a pilot. | Native route documented; end-to-end mobile behavior untested |
| LaunchDarkly | Developer $0; Foundation usage pricing beyond free allowances. Developer for experiments within quota; Foundation for overage usage. | Engineering team combining release controls and experiments | partly meets: Native SDK route documented; exact SDK/version, exposure, offline and assignment behavior require a pilot. | Native route documented; end-to-end mobile behavior untested |
| Amplitude Experiment | Growth/Enterprise: custom quote for experiment results. Growth/Enterprise for experiment results per current matrix; custom quote. | Team already using Amplitude and budgeting for experiment analysis | partly meets: Native experimentation route exists; results require a qualifying paid quote and SDK validation. | Native route documented; end-to-end mobile behavior untested |
| Optimizely | Custom quote; no public numeric minimum verified. Web Experimentation or Feature Experimentation specified in quote. | Team procuring a distinct Web or Feature Experimentation product | partly meets: Feature Experimentation SDKs documented; specify native platform and product edition in the quote. | Native route documented; end-to-end mobile behavior untested |
Pricing and plan facts checked 2026-11-12. Prices are USD unless stated otherwise; annual equivalents require an annual commitment. Rows are scenario comparisons, not an overall ranking.
Assessment scope: A documented native-app route is a candidate for a pilot; exact SDK/version, exposure, offline and assignment behavior remain procurement conditions. “Meets” describes this narrow shortlist condition; “partly meets” preserves an unresolved requirement. “Does not meet” identifies a mismatch, and “not verified” means evidence is missing. Confidence concerns the cited evidence, not customer satisfaction. This review does not certify each vendor’s statistical assumptions, permitted stopping rules or automated guardrail enforcement. Those remain explicit verification questions before launching an experiment.
Reviews actually read in this guide’s research: Firebase 3 across 3 platforms; Statsig 5 across 2 platforms; GrowthBook 5 across 1 platform; PostHog 5 across 2 platforms; LaunchDarkly 5 across 2 platforms; Amplitude Experiment 7 across 1 platform; Optimizely 5 across 1 platform. These accessible samples are not representative; fewer than five reviews or a single platform falls short of the research target. The examples below are selected observations, not a claim that every sampled review is discussed.
Firebase suits teams whose experiment can be expressed through Remote Config and Analytics. Its A/B Testing documentation covers Android and iOS, with a parameter-based workflow that requires app implementation. The A/B Testing product is listed at no cost, but Remote Config now has usage pricing: the first 100,000 fetches per day per project are free, with paid usage above that threshold. A blanket claim that the whole workflow is always free would be misleading. Firebase experiment setup, Firebase pricing.
Statsig is a candidate for teams ready to instrument product experiments. Its client SDK documentation includes mobile implementations, while Developer provides two million metered events monthly. Exposure and metric volume matter to cost, even when flag checks are unlimited. Confirm the exact SDK's experiment behavior and the billable events generated by your app. Statsig client SDKs, Statsig pricing.
GrowthBook offers mobile SDK options within a flexible implementation approach. Cloud Starter allows three users and one project with unlimited experiments and traffic. That does not remove the work of supplying reliable events and metrics. Evaluate the SDK and data connection together, including who will maintain them. GrowthBook SDKs, GrowthBook pricing.
PostHog is worth considering when product analytics is part of the purchase. Its experiment product page lists Android, iOS, React Native, and Flutter support. Verify the framework-specific implementation and account for analytics events separately from feature-flag requests. PostHog experiment capabilities, PostHog pricing.
LaunchDarkly deserves attention when experiments accompany controlled releases. Its SDK documentation identifies mobile experimentation support, and Developer includes A/B tests within limits of 1,000 client-side monthly active users and five service connections. Estimate client and backend usage separately if the experiment spans both. LaunchDarkly SDKs, LaunchDarkly pricing.
Amplitude and Optimizely are conditional candidates. Amplitude provides native SDKs, but its current pricing matrix gates experiment results to Growth and Enterprise despite smaller plans having active-experiment allowances. Optimizely documents iOS and Android in Feature Experimentation; that is the product to verify in a mobile quote, rather than assuming its Web product covers the app. Amplitude SDKs, Amplitude pricing, Optimizely supported languages.
Evaluate a delayed outcome, not just an instant click
For the hypothetical learning app, finishing onboarding could be an early diagnostic. A more meaningful primary outcome might be completing a first lesson within a predefined window. A paid subscription or renewal requires another measurement definition and a reliable transaction source.
Ask the vendor to demonstrate an outcome arriving after the app closes and reopens. Include duplicate event delivery and a late-arriving event. The objective is to understand deduplication and attribution behavior, not to assume every SDK handles those cases identically.
A retention experiment also needs time for cohorts to mature. Comparing users with a full follow-up window against people who enrolled yesterday can create an apparent difference unrelated to the change. Specify eligibility dates and the observation window before launch, and confirm how the results interface treats incomplete follow-up.
Keep app stability visible alongside the business metric. Decide which crash, error, or performance signals would stop a rollout and who can act. A positive engagement result does not automatically justify shipping an experience that creates unacceptable failures for a subgroup.
Match the tool to the team's operating maturity
A team starting its first app experiments needs stable identity, a documented event plan, and a developer who can verify the SDK integration. The initial purchase should support those foundations without making the experiment owner dependent on unexplained reports.
A team running regular tests needs a repeatable device and version QA process. Its review should cover supported versions, login transitions, slow connectivity, fallback behavior, and internal test accounts. The platform demonstration should show how to inspect those cases, including what evidence remains after a configuration changes.
A larger program needs clearer ownership of metrics and release decisions. Ask about approval requirements, access controls, experiment conflicts, audit history, and export rights. These are plan-specific requirements to establish in writing, not features to infer from a vendor's reputation. The maturity assessment helps identify which process gaps matter first.
What user reviews can and cannot establish
In a June 2025 SoftwareReviews entry, Firebase user Shannon G., working in information technology, valued the connection between analytics and configuration but found experiment interpretation difficult. The platform labels the review verified and discloses a gift-card incentive. The interpretation complaint is a historical user perception, not evidence that a particular statistical feature is currently absent. Read Shannon G.'s review.
LaunchDarkly reviewer Parth K., a software engineer, praised reverting production changes in an October 29, 2026 G2 review and raised questions about targeting-rule precedence. It is marked validated, incentivized, and seller-invited. His use case concerns data pipelines, so it informs release-control questions; it is not direct evidence of mobile experimentation quality. Read Parth K.'s review.
These selected reviews help identify issues to investigate. They do not provide a representative satisfaction ranking or a controlled comparison. A mobile buyer should prefer demonstrations on the intended SDK over extrapolating from a highly rated web or backend use case.
Make a small implementation prove the fit
Request an evaluation around one instrumented screen and one outcome. Have the engineer demonstrate supported and unsupported app versions, an anonymous-to-signed-in transition, and the intended fallback. Have the analyst explain which users enter the result and when their outcomes become eligible for analysis.
Estimate statistical feasibility before expanding the test. The sample-size calculator can provide an initial check for a simple design; more complicated retention, clustering, or repeated-measurement designs need assumptions appropriate to that analysis. A large install count is not the same as a large eligible experiment population.
Price the resulting workload, including events, requests, active users, supporting services, and engineering maintenance. Ask what happens at the quota boundary and how to recover the underlying assignments and outcomes if you leave. Unknowns on those points should remain conditions of the purchase.
Use GrowthLayer's tool directory to compare the wider shortlist. GrowthLayer is also operated by Atticus Li. This guide's version and exposure questions provide the mobile-specific procurement brief to take into that comparison.
FAQ
Is Firebase A/B Testing completely free?
Firebase lists A/B Testing itself at no cost. Its current pricing includes a free Remote Config fetch allowance and paid usage above it. Check supporting services and the app's fetch behavior before treating the complete implementation as free.
Can a no-code website testing tool test a native app?
A website editor does not establish native-app support. Ask for the exact mobile SDK, supported framework, experiment implementation, and result-analysis plan. Remote parameters can simplify later changes, but the app must first implement the relevant behavior.
Which tool is best for a subscription app?
Shortlist tools that can preserve assignment through login and connect exposure to verified subscription outcomes. Then evaluate the follow-up window, SDK fit, operating cost, and release controls. A tool that measures paywall taps alone cannot establish subscription revenue.