PostHog is a product analytics platform. It wants identified users, funnels that survive login, session replay, feature flags, experiments, surveys, and (if you self-host) the warehouse-shaped control that implies. SiteLine is cookieless website analytics plus a durable Google Search Console import. Comparing them as “analytics tools” is how you buy the wrong one. PostHog is not worse at traffic; it is a different job. SiteLine is not worse at product analytics; it does not do product analytics.
The jobs, without a scorecard
PostHog: what did this user do in the product? Where did they drop in a multi-step flow? What flag were they on? What did the session look like? You will use cookies or an identified distinct_id because that is the point. Self-host or Cloud. Websites can send pageviews into PostHog, but you are paying for a product OS, not a 10 KB cookieless snippet.
SiteLine: what did the site do, without an analytics cookie, and what did Google Search do for this property over time? Visitor identity is a daily hash: truncated IP (/24 v4, /48 v6) + user agent + daily salt, reset every day. Collect omits credentials. Search Console is read-only, 16-month backfill, 25k rows/day, kept while you subscribe, about two days lag. Goals and funnels are path/event rules in the UI. MCP is read-only access for agents. No replay, no heatmaps, no user profiles, no flags, no warehouse, no self-host.
If you need both jobs, you run both. Plenty of teams should.
Comparison
| SiteLine | PostHog | |
|---|---|---|
| Job | Cookieless site analytics + durable GSC | Product analytics and feature platform |
| Identity | Daily hash; no analytics cookie | Users, persons, distinct_id; cookies typical |
| Replay / heatmaps / flags | No | Yes (core PostHog) |
| Search Console | First-class import (16 months, 25k rows/day, keep while subscribed) | Not the product |
| Self-host | No | Yes (or Cloud) |
| Funnels | UI, anonymous daily visitors | Identified (or anonymous) product funnels |
| MCP | Yes | Their own APIs / LLM tooling; different stack |
| Price | $4.99 / $19.99 / $99.99 + overage, 7-day trial | Free tier then usage (events, recordings, etc.) |
Do not use SiteLine as a PostHog substitute
SiteLine funnels will not tell you that user 8491 completed onboarding after a flag change. The visitor hash expires at midnight UTC (salt rotation). There is no person record to attach a trait to. Custom events exist — you can send signup_completed with a short property payload — but they are site events, not a CDP. Event names and properties have tight limits; this is not an arbitrary JSON warehouse.
PostHog will not backfill 16 months of Search Console at 25k rows/day and keep the days Google expired. You can warehouse GSC yourself and join it in PostHog’s SQL, if you like operating that. That project is not “SiteLine but open source.” It is a data pipeline.
Privacy is not a ranking
PostHog can be run in a more private configuration; it can also record sessions and identify emails. The default job pulls you toward personal data. SiteLine’s default job is cookieless traffic plus GSC (which is Google’s search-performance data, imported read-only — not a pageview pixel from Google Analytics). Read /docs/privacy. If legal wants “no SaaS pageviews,” PostHog self-host or Matomo or Umami is the conversation. SiteLine will lose that conversation on purpose.
When SiteLine is the right half
Marketing and SEO teams who need on-site counts without a cookie, plus query/page history that survives Google’s 16-month window. Install: /docs/script. Goals: /docs and the goals page. Proxy: DIY. Trial: 7 days, /register. Plans: $4.99 / $19.99 / $99.99+overage. Unlimited GSC properties on paid tiers.
When PostHog is the right half: product, growth, and engineering teams who need persons, replay, and flags. SiteLine vs Mixpanel is the other product-analytics comparison. For cookieless traffic peers, start at SiteLine vs Plausible.
FAQ
Can SiteLine do session replay like PostHog?
No. SiteLine does not ship replay, heatmaps, or user profiles. If replay is required, PostHog (or Matomo’s plugin) is the tool. That is a different consent and data-retention conversation than cookieless pageviews.
Can PostHog replace SiteLine for Search Console?
Only if you build an import. SiteLine’s GSC path is the product: read-only OAuth, 16-month backfill, 25,000 rows/day, including fresh data before Google finalizes it, retained while you subscribe, MCP. PostHog’s product is persons and product events.
Is SiteLine cookieless?
Yes for the tracker: no analytics cookie, credentials omitted, daily truncated-IP + UA hash. It is still a hosted collector. GSC data is Google’s search performance, imported with a read-only scope. Details: /docs/privacy.