diff --git a/packages/backend-core/src/environment.ts b/packages/backend-core/src/environment.ts
index e064398153..6377d682d0 100644
--- a/packages/backend-core/src/environment.ts
+++ b/packages/backend-core/src/environment.ts
@@ -145,6 +145,7 @@ const environment = {
   COOKIE_DOMAIN: process.env.COOKIE_DOMAIN,
   PLATFORM_URL: process.env.PLATFORM_URL || "",
   POSTHOG_TOKEN: process.env.POSTHOG_TOKEN,
+  POSTHOG_PERSONAL_TOKEN: process.env.POSTHOG_PERSONAL_TOKEN,
   POSTHOG_API_HOST: process.env.POSTHOG_API_HOST || "https://us.i.posthog.com",
   ENABLE_ANALYTICS: process.env.ENABLE_ANALYTICS,
   TENANT_FEATURE_FLAGS: process.env.TENANT_FEATURE_FLAGS,
diff --git a/packages/backend-core/src/features/index.ts b/packages/backend-core/src/features/index.ts
index d3f00af87d..5305da4764 100644
--- a/packages/backend-core/src/features/index.ts
+++ b/packages/backend-core/src/features/index.ts
@@ -10,6 +10,7 @@ export function init(opts?: PostHogOptions) {
     console.log("initializing posthog client...")
     posthog = new PostHog(env.POSTHOG_TOKEN, {
       host: env.POSTHOG_API_HOST,
+      personalApiKey: env.POSTHOG_PERSONAL_TOKEN,
       ...opts,
     })
   } else {
@@ -186,10 +187,23 @@ export class FlagSet<V extends Flag<any>, T extends { [key: string]: V }> {
       tags[`identity.tenantId`] = identity?.tenantId
       tags[`identity._id`] = identity?._id
 
-      if (posthog && identity?.type === IdentityType.USER) {
+      // Until we're confident this performs well, we're only enabling it in QA
+      // and test environments.
+      const usePosthog = env.isTest() || env.isQA()
+      if (usePosthog && posthog && identity?.type === IdentityType.USER) {
         tags[`readFromPostHog`] = true
 
-        const posthogFlags = await posthog.getAllFlagsAndPayloads(identity._id)
+        const personProperties: Record<string, string> = {}
+        if (identity.tenantId) {
+          personProperties.tenantId = identity.tenantId
+        }
+
+        const posthogFlags = await posthog.getAllFlagsAndPayloads(
+          identity._id,
+          {
+            personProperties,
+          }
+        )
         console.log("posthog flags", JSON.stringify(posthogFlags))
 
         for (const [name, value] of Object.entries(posthogFlags.featureFlags)) {
diff --git a/packages/backend-core/src/features/tests/features.spec.ts b/packages/backend-core/src/features/tests/features.spec.ts
index 9c928f5545..1b6a6e041b 100644
--- a/packages/backend-core/src/features/tests/features.spec.ts
+++ b/packages/backend-core/src/features/tests/features.spec.ts
@@ -153,6 +153,7 @@ describe("feature flags", () => {
         mockPosthogFlags(posthogFlags)
         env.POSTHOG_TOKEN = "test"
         env.POSTHOG_API_HOST = "https://us.i.posthog.com"
+        env.POSTHOG_PERSONAL_TOKEN = "test"
       }
 
       const ctx = { user: { license: { features: licenseFlags || [] } } }
@@ -160,7 +161,11 @@ describe("feature flags", () => {
       await withEnv(env, async () => {
         // We need to pass in node-fetch here otherwise nock won't get used
         // because posthog-node uses axios under the hood.
-        init({ fetch: nodeFetch })
+        init({
+          fetch: (url, opts) => {
+            return nodeFetch(url, opts)
+          },
+        })
 
         const fullIdentity: IdentityContext = {
           _id: "us_1234",