Companies Using PostHog

As of our March 2026 crawl. We've identified 20,939 domains running PostHog, with 10,580 enriched company profiles matched to LinkedIn data. PostHog is a Y Combinator-backed (W20) open-source product analytics platform that went from zero to 20,000+ detected domains in five years. That's one of the steepest adoption curves we've tracked for any analytics tool. Here's what the data tells us about who's actually running it.

Growth Trajectory

PostHog's growth is extraordinary by any measure. Our detection data shows it went from essentially zero in early 2020 to 13,733 active domains by July 2025. Active domains doubled from ~3,600 in March 2024 to ~8,000 by January 2025 -- a 122% increase in 10 months. Growth accelerated further in H1 2025, adding another 5,700+ domains. For context, Mixpanel (founded 2009) sits at 19,474 domains. PostHog is on track to surpass it within a year.

“PostHog's growth rate is the fastest we've recorded for any open-source analytics platform. Doubling active domains in 10 months, then adding another 5,700 in the next six, puts it on a trajectory to overtake tools that have been in market for over a decade.” — Mehmet Suleyman, CEO at TechnologyChecker.io

Sales Signal: PostHog's rapid expansion means its customer base is full of recent adopters still evaluating their stack. Companies that added PostHog in the last 12 months are the most receptive to complementary tools -- session replay integrations, data warehouse connectors, and CDP platforms.

Customer Profile

PostHog's customer base is overwhelmingly small and young. 69.8% of companies have 1-10 employees, and combined with the 11-50 bracket, 89.2% have fewer than 50 people. Age data backs this up: 45.2% were founded in the 2020s and another 34.7% in the 2010s, meaning nearly 80% of PostHog customers are less than 15 years old. These are digital-native startups, not legacy businesses modernizing.

The enterprise exceptions are telling: Siemens (1847), The World Bank (1944), UNICEF (1946), and NEC (1899) all appear in our data, but they're running PostHog on specific internal tools or subdomain projects. PostHog's published customer list, which includes ElevenLabs and Lovable, confirms the developer-tool focus.

Sales Signal: The 89.2% sub-50-employee concentration means PostHog's audience is founder-led, engineering-heavy, and budget-conscious. PLG (product-led growth) motions outperform enterprise sales approaches with this segment. If you're selling to PostHog users, lead with developer documentation and free tiers.

Industry and Geographic Concentration

Software Development (16.9%), Technology/Internet (10.5%), and IT Services (4.5%) together account for 31.9% of PostHog's customer base. Real Estate at 12.8% is the surprise -- likely proptech startups and property management SaaS rather than traditional agencies. Financial Services (3.2%) is also notable, with Citizens Bank and Bank of Georgia suggesting PostHog is gaining trust in regulated sectors.

Geographically, the United States leads at 52.5%, followed by the UK (6.6%), Canada (4.3%), and Spain (4.2%). The Spanish adoption is unusually high and may reflect PostHog's European data hosting options. Germany (3.2%), France (2.7%), and India (2.3%) round out the top countries.

Sales Signal: The 31.9% tech-industry concentration makes PostHog's customer list a high-quality prospect pool for developer tools, infrastructure services, and API-first products. Target the US (52.5%) for volume and the UK/Spain corridor for European expansion.

Migration Patterns

Google's forced deprecation of Universal Analytics was PostHog's biggest growth driver. The largest inbound migration comes from Google Universal Analytics (4,490 companies), with 1,223 arriving in the last year alone. PostHog also gained 1,950 from GA4 and 1,552 from Global Site Tag. These aren't analytics novices switching tools for fun -- they're teams forced to re-evaluate who found PostHog offers what GA4 doesn't: product analytics, session replay, and feature flags in one platform.

The outbound side skews heavily toward the pre-2022 period (early adopters who tried PostHog and reverted). Recent 1-year data shows PostHog gaining 1,223 from Google UA vs. losing only 27 -- a 45:1 ratio. Against GA4, the 1-year ratio is 3:1 in PostHog's favor (1,051 gained vs. 347 lost).

“The 45:1 gain-to-loss ratio against Google Universal Analytics is the most lopsided migration pattern in our entire dataset. Google's UA deprecation didn't just create churn -- it created a generation of analytics switchers who now evaluate tools differently.” — Mehmet Suleyman, CEO at TechnologyChecker.io

Sales Signal: Companies that migrated from Google UA to PostHog in the last year are actively rebuilding their analytics infrastructure. They're also likely evaluating CDPs, data warehouses, and experimentation tools. Time your outreach to this “stack rebuild” window.

Technology Ecosystem

PostHog's tech stack data confirms its developer-first positioning. React (61.3%) and Next.js (41.3%) dominate the frontend, while Cloudflare (64.3%) and AWS (53.6%) split the infrastructure. Vercel at 23.2% is four times its web-wide average, confirming PostHog users are on the modern Jamstack. Sentry (33.0%) appears more often with PostHog than with most analytics platforms.

Here's the surprise: Google Analytics (75.1%) and GA4 (63.9%) both show extremely high overlap. Most PostHog users run it alongside Google Analytics, not as a replacement. PostHog handles product analytics and experimentation; Google handles marketing attribution. Google Tag Manager at 78.8% further confirms these are teams that care about tag management and data routing.

Sales Signal: The 41.3% Next.js and 23.2% Vercel overlap tells you exactly where to find PostHog users: modern JavaScript communities, Vercel's ecosystem, and React-focused developer forums. These are high-intent channels for developer tools.

G2 Review Signals

With 1,281 review mentions on G2, the signal is strong. PostHog scores highest for ease of use (229 mentions) and easy setup (185 mentions), which tracks with our data showing micro-business dominance -- small teams need tools that work out of the box. The leading concern is steep learning curve (115 mentions), along with initial setup complexity (64 mentions) and confusing dashboard organization (64 mentions).

That's a paradox worth noting: “easy to set up” but “steep learning curve.” The likely explanation is that basic installation is simple (drop in a JavaScript snippet), but mastering funnels, cohorts, and feature flag workflows takes time. The session recordings (138 mentions) as a top pro validates PostHog's bundled approach.

Sales Signal: The “steep learning curve” complaint (115 mentions) creates an opening for onboarding services, training, and analytics consulting. If you sell implementation help, PostHog's customer base has a documented need for it.

Key Takeaways

1. Fastest-growing open-source analytics platform. 122% active domain growth in 10 months, with trajectory to pass Mixpanel in 2026.

2. 89% sub-50-employee, 80% post-2010 companies. PostHog's audience is overwhelmingly small, young, and developer-led.

3. Google UA deprecation was the primary growth catalyst. 4,490 companies migrated from Google UA, with a 45:1 recent gain-to-loss ratio.

4. Complement, not replacement. 75% of PostHog users also run Google Analytics. PostHog handles product analytics; Google handles acquisition.

5. Modern dev stack marker. 61% React, 41% Next.js, 23% Vercel. PostHog users are a distinct “modern developer” segment.

Sales Applications

Outreach Template: “Hi [Name], I saw [Company] recently adopted PostHog. Based on our data across 10,580 PostHog companies, teams in your stage typically pair it with [CDP / data warehouse / experimentation tool]. We help [specific value]. Would a quick call make sense?”

Targeting Strategy: Filter for US-based software companies with 1-50 employees founded after 2018. Cross-reference with Vercel/Next.js usage for the highest-intent segment. Use developer community channels (GitHub, Discord, Hacker News) over traditional email.

Competitive Angle: Against Hotjar and FullStory, PostHog bundles session replay with product analytics and feature flags. Against Mixpanel, PostHog is open-source and self-hostable. Against GA4, PostHog wins on product analytics but loses on marketing attribution -- most users keep both.

TechnologyChecker.io tracks 10,580 enriched PostHog companies across 29.6 million domains. Use our platform to build targeted prospect lists by company size, industry, tech stack, and migration status.