The best Optimizely alternatives & competitors, compared
Contents
1. PostHog
- Founded: 2020
- Similar to: VWO, LaunchDarkly
- Typical users: Engineers and product teams
- Typical customers: Mid-size B2Bs and startups

What is PostHog?
PostHog (that's us 👋) is an open-source platform that includes A/B testing, feature flags, product analytics, session replay, and user surveys. This means it's also an alternative to tools like Mixpanel (product analytics) and Hotjar (session replay and surveys).
Typical PostHog users are engineers and product managers at startups and mid-size companies. Customers include Supabase, ElevenLabs, and Airbus.
According to BuiltWith, as of April 2024, 5,610 (0.5%) of the top 1 million websites use PostHog. This is slightly more than Optimizely's 5,353.
Key features
Feature flags: Safely rollout features with local evaluation (for faster performance), JSON payloads, and instant rollbacks.
A/B tests: Up to 9 test variations, primary and secondary metrics. Automatically calculate test duration, sample size, and statistical significance.
Product analytics: Funnels, user paths, retention analysis, custom trends, and dynamic user cohorts. Also supports SQL insights for power users.
Surveys: Target surveys by event or person properties. Templates for net promoter score (NPS), product-market fit (PMF) surveys, and more.
Session replays: Including event timelines, console logs, network activity, and 90-day data retention.
How does PostHog compare to Optimizely?
The core of feature flags and experimentation are similar between the two. The big difference is that PostHog is free, open-source, and has analytics built in, while Optimizely has a range of enterprise content, commerce, and collaboration tools.
Why do companies use PostHog?
According to reviews on G2, companies use PostHog because:
It replaces multiple tools: PostHog can replace Optimizely (feature flags and A/B testing), Mixpanel (analytics), and Pendo (feedback and session replays). This simplifies workflows and ensures all your product data is in one place.
Pricing is transparent and scalable: Reviewers appreciate how PostHog's pricing scales as they grow. There's a generous free tier they can use forever. Companies eligible for PostHog for Startups also get $50k in additional free credits.
They need a complete picture of users: PostHog includes every tool necessary to understand users and improve products. This means creating funnels to track conversion, watching replays to see where users get stuck, testing solutions with A/B tests, and gathering feedback with user surveys.
Bottom line
Being free, self-serve, and sharing many of the same features, PostHog is a great alternative to Optimizely. This is especially true for startups and scale-ups looking for dev tools, though marketing teams may prefer Optimizely for experiments due to its visual editor.
2. VWO
- Founded: 2009
- Similar to: PostHog, Optimizely
- Typical users: Product managers, engineers, UX designers
- Typical customers: Enterprise B2B and B2C companies optimizing customer experiences

What is VWO?
VWO is a digital experience optimization platform that aims to maximize conversion with tools like A/B testing, personalization, funnels, heatmaps, session replay, and customer analytics.
The VWO platform is home to multiple different products including testing, insights, data, personalize, plan, and web rollouts each with its own feature sets and pricing.
According to BuiltWith, 9,183 of the top million sites use VWO as of April 2024. This is nearly double Optimizely's 5,353.
Key features
A/B testing: Improve and optimize experiences and conversions with web, mobile, and server-side A/B testing.
Data platform: Collect and analyze customer data across your stack using SDKs, third-party integrations, and direct uploads.
Insights: Understand your users with session recordings, heatmaps, analytics, and surveys.
Personalization: Create and tailor user journeys and campaigns for specific audiences, locations, and times.
Planning: Ideate, prioritize and plan optimization campaigns in one location. Connect them directly to data as well.
How does VWO compare to Optimizely?
Optimizely and VWO are both massive, multi-product platforms with many similarities. They both focus on optimizing user experience and have tools like A/B tests, visual editors, program planners, and personalization to help with this.
The difference is that Optimizely has CMS and content tools while VWO has more product tools like session replays, surveys, and behavioral analytics.