One source.
Every answer.
Product analytics, feature flags, and behavioral campaigns — on a single event pipeline you can trust.
$ npm install kilden // app.js kilden.init('wk_...') kilden.track('checkout_completed', { amount: 29990 })
Four products. One pipeline.
Product analytics
Funnels, trends and retention over every event you capture — no sampling, no separate tracking plan. If it happened, you can query it.
Feature flags
Target releases by real behavioral cohorts — not just user properties. Evaluation under 5ms, instant kill-switch when things go wrong. Try the toggle.
Behavioral campaigns
Emails triggered by what users do — cancelled the moment they convert. Campaign metrics re-enter the pipeline as plain events, so open→click→convert is just another funnel.
Session replay
Watch the sessions behind every funnel drop-off. Same events, same identity — jump from a chart straight to the recordings that explain it.
Identity you can verify
Events from authenticated users are verified with a JWT signed by your backend. Nobody can spoof a user_id from the browser console — spoofing is impossible, not just unlikely.
One pipeline, zero drift: every feature reads from the same events. Your funnel, your flag targeting and your campaign triggers can never disagree.
// your backend signs, kilden verifies const token = jwt.sign({ sub: user.id }, KILDEN_SECRET) kilden.identify(user.id, { plan: 'pro' }, { token }) // → Authorization: Bearer <token> // → distinct_id verified ✓ spoofed events rejected ✕
Stop filing tickets for data.
Your engineers install it once. From then on, every funnel, cohort and campaign is self-serve — no SQL, no tracking plan meetings, no waiting for the next sprint.
› Install kilden (npm package "kilden") in this project. Init it with my write key from app.kilden.io/settings, enable autocapture, and add a kilden.track() call to our main conversion event. Docs: docs.kilden.io/install
The free tier is the product, not a demo.
Free
free forever, not a trialPay as you go
prices coming soonWhat one pipeline unlocks
Recover abandoned carts
An email that cancels itself the moment the user converts. No “you left something behind” after they already bought.
Ship behind flags
Roll out to cohorts built from real behavior — “used search this week”, “completed onboarding” — not static user lists.
Onboarding that adapts
Sequences driven by what each user actually did — skip the steps they finished, nudge the ones they didn’t.
A/B test on the same numbers
Split traffic with a flag, measure both variants in the same funnel. No exporting events to a separate experiments tool.
Marketing on autopilot
Upgrade nudges, win-back emails, usage milestones — triggered by behavior, running without anyone pressing send.
Catch churn before it happens
Cohort of “active last month, quiet this week” → re-engagement campaign fires automatically. Growth loops, not dashboards.
Questions, answered honestly
How is this different from PostHog or Mixpanel? +
Two things. First, verified identity: authenticated events carry a JWT signed by your backend, so nobody can spoof a user from the console. Second, one pipeline — analytics, flags and campaigns all read the same events, so your numbers never drift between tools.
Where does my data live? +
In Kilden’s cloud, in a dedicated ClickHouse + Postgres store per workspace. You can export everything at any time — your events are yours.
What are the team limits? +
None. Unlimited members on every plan, including Free. We charge for usage, not for people.
What does “coming soon” actually mean? +
It means it isn’t built yet. We label the roadmap honestly instead of selling features that don’t exist — campaigns and session replay are next, in that order.
Can I self-host? +
TBD. The architecture doesn’t rule it out, but we haven’t committed to supporting it yet. If it matters to you, tell us — it shapes the roadmap.