Use PostHog if you already run it and have time to build the price swap. Use PricingFast if you want a Stripe price test without writing the plumbing.
- PostHog experiments are feature flags plus stats; revenue comes from Stripe data you link in its warehouse.
- You build the price swap, the checkout link, the fallback and the clean-up.
- PricingFast does those parts for Stripe prices, and only those.
What PostHog is
PostHog is a product analytics suite. Its experiments are backed by feature flags that randomize users into variants, with Bayesian or frequentist statistics. To score a test on Stripe revenue, you sync Stripe into PostHog’s data warehouse and join Stripe customers to your users.
Facts about PostHog come from its public docs, checked October 2026. See the sources at the end. Spotted something out of date? Tell us and we’ll fix it.
Side by side
| PostHog | PricingFast | |
|---|---|---|
| Built for | Any product experiment | Stripe price tests |
| Test price in Stripe | You create it | Created for you |
| Show the price and the right checkout | Your code reads the flag | Built in |
| Revenue per variant | Stripe sync + customer join you set up | Built in, per visitor |
| Stats | Bayesian (default) or frequentist | 95% confidence and 30 sales on revenue per visitor |
| If the service is slow | Depends on your flag code | Your prices within 1.5 s |
| Ending the test | You archive prices and remove code | Pick the price to keep; the other is archived |
| Price | Free for the first 1M flag requests a month | $79/mo or $790/yr, first test free |
Built for
- PostHog
- Any product experiment
- PricingFast
- Stripe price tests
Test price in Stripe
- PostHog
- You create it
- PricingFast
- Created for you
Show the price and the right checkout
- PostHog
- Your code reads the flag
- PricingFast
- Built in
Revenue per variant
- PostHog
- Stripe sync + customer join you set up
- PricingFast
- Built in, per visitor
Stats
- PostHog
- Bayesian (default) or frequentist
- PricingFast
- 95% confidence and 30 sales on revenue per visitor
If the service is slow
- PostHog
- Depends on your flag code
- PricingFast
- Your prices within 1.5 s
Ending the test
- PostHog
- You archive prices and remove code
- PricingFast
- Pick the price to keep; the other is archived
Price
- PostHog
- Free for the first 1M flag requests a month
- PricingFast
- $79/mo or $790/yr, first test free
When PostHog fits better
- You already use PostHog and want every experiment in one place.
- You want to test more than prices: onboarding, copy, features.
- You have an engineer with a day or two for the plumbing, and you want the free tier.
When PricingFast fits better
- You want a price test this week, installed by your coding agent.
- You don’t want to join Stripe customers to analytics users yourself.
- You want a fixed stop rule and a safe fallback on your checkout without writing them.
Switching from PostHog
- 1
Keep PostHog for analytics
The two run side by side. PricingFast only handles the price on your pricing page.
- 2
Remove any price flag code
So the two tools don’t both change the price.
- 3
Install PricingFast with your coding agent
Rehearse on localhost, then press Launch.
Questions
Can you A/B test pricing with PostHog?
Yes. Create the test price in Stripe, use a PostHog feature flag to show it to part of your users and send them to the matching checkout, sync Stripe into PostHog's data warehouse, and use Stripe revenue as the experiment metric.
Is PostHog free for price tests?
PostHog bills experiments through feature flag requests, and the first 1 million a month are free. Stripe data in the warehouse is free for the first 1 million rows a month.
Can I use PostHog and PricingFast together?
Yes. Keep PostHog for analytics and let PricingFast handle the price test. Just don't change the price with a PostHog flag at the same time.
Sources
- [1]Experiments, PostHog docs
- [2]Experiments: start here, PostHog docs
- [3]Experiment statistics, PostHog docs
- [4]Data warehouse metrics in experiments, PostHog docs
- [5]Revenue analytics, PostHog docs