PostHog in a Figma plugin, compared with tode

PostHog runs in the plugin iframe with memory persistence and brings funnels, flags and replay. What that buys a plugin developer, and what it asks in return.

PostHog is the most capable thing you can put inside a plugin iframe: events, funnels, retention, feature flags, surveys and session replay from one SDK. It runs there once you tell it to keep state in memory. Whether you want all of that in a side panel is the real question, and it is a question about your plugin, not about PostHog.

Running PostHog in a plugin

posthog-js defaults to cookies plus localStorage for its distinct id. Both are unavailable in a null-origin frame, so you switch persistence to memory and identify the user yourself. Pageviews are meaningless in a plugin, so turn them off; autocapture is your call.

// ui.ts
import posthog from 'posthog-js';

posthog.init('phc_...', {
  api_host: 'https://us.i.posthog.com',   // or eu.i.posthog.com
  persistence: 'memory',
  capture_pageview: false,
  autocapture: false,
});

window.onmessage = (e) => {
  const msg = e.data.pluginMessage;
  if (msg?.type === 'identity' && msg.userId) posthog.identify(msg.userId);
};

posthog.capture('fonts_replaced', { count: 12 });

"networkAccess": { "allowedDomains": ["https://us.i.posthog.com"] }

With memory persistence a new anonymous id is created on every open until identify runs, so call it before the first capture or you will see one-event anonymous users next to your real ones. Session duration follows PostHog's own session rules, which are built around a tab staying open and the user staying active. For a plugin that is open for forty seconds those rules mostly work; just do not expect the number to match "time the UI was open" exactly.

Side by side

	PostHog	tode
Works in the null-origin iframe	Yes, with memory persistence	Yes
User identity	You pass the Figma user id to `identify`	Read from `figma.currentUser` at init
Session length	PostHog's session model	Time the UI connection is open
Retention and stickiness	Yes, configurable	Yes, fixed definitions
Funnels, flags, surveys, replay	Yes	No
Figma editor and mode	Send them as properties	Attached to every event
Data region	US or EU cloud, or self-hosted	One region
Event types	Unlimited	2 on Free, 20 on Starter, unlimited above
Price model	Free tier, then by usage per product	Free for 1 plugin, then one flat price for all your plugins
Bundle weight in the UI	The full SDK, more if replay is on	A small adapter

Pick PostHog if

You want to watch a replay of someone getting stuck in your plugin. Nothing else on this list does that, and for a UI-heavy plugin it is worth a lot. Or you want feature flags to roll a change out to a tenth of your users. Or you already use PostHog for the rest of your product.

Pick tode if

You want the usage numbers for a plugin or a handful of them, you do not want replay or flags, and you would rather have session length and identity handled than configured. The narrower data model is also the privacy story: there is no way to send more than a name and a number, which is easy to describe in a Community listing. See what a plugin knows about its users for the full list of what is stored.