posthog-js feat(flags): Add real-time feature flags support

Introduce a new realtime_flags configuration option that enables real-time feature flag updates through Server-Sent Events (SSE). When enabled, the SDK establishes a persistent connection to receive flag updates without polling.

Key changes:

Add realtime_flags config option (default: false)
Implement SSE connection management in PostHogFeatureFlags
Auto-reconnect on connection errors with 5-second delay
Clean shutdown of SSE connection

Oct 31 '25 14:10 gustavohstrassburger

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Project	Deployment	Review	Updated (UTC)
posthog-js	Ready	Preview	Dec 15, 2025 2:48pm
posthog-nextjs-config	Ready	Preview	Dec 15, 2025 2:48pm

Oct 31 '25 14:10 vercel[bot]

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Oct 31 '25 14:10 github-actions[bot]

Download bundle size visualization

Oct 31 '25 15:10 github-actions[bot]

Size Change: +8.22 kB (+0.16%)

Total Size: 5.2 MB

Filename	Size	Change
`packages/node/dist/client.js`	24.2 kB	+63 B (+0.26%)
`packages/node/dist/client.mjs`	22.4 kB	+63 B (+0.28%)
`packages/node/dist/extensions/feature-flags/feature-flags.js`	35.1 kB	+4.25 kB (+13.76%)	⚠️
`packages/node/dist/extensions/feature-flags/feature-flags.mjs`	32.7 kB	+3.84 kB (+13.31%)	⚠️

ℹ️ View Unchanged

Filename	Size
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_{compressed-size-action}

Oct 31 '25 15:10 github-actions[bot]

This PR hasn't seen activity in a week! Should it be merged, closed, or further worked on? If you want to keep it open, post a comment or remove the stale label – otherwise this will be closed in another week.

Nov 10 '25 09:11 posthog-bot

Wiz Scan Summary

Scanner	Findings
Vulnerabilities	12 7 6
Sensitive Data	-
Secrets	-
IaC Misconfigurations	-
SAST Findings	-
Software Supply Chain Findings	-

Total	12 7 6

View scan details in Wiz

To detect these findings earlier in the dev lifecycle, try using Wiz Code VS Code Extension.

Nov 19 '25 12:11 wiz-7ad640923b[bot]

This PR hasn't seen activity in a week! Should it be merged, closed, or further worked on? If you want to keep it open, post a comment or remove the stale label – otherwise this will be closed in another week.

Nov 27 '25 09:11 posthog-bot

This PR was closed due to lack of activity. Feel free to reopen if it's still relevant.

Dec 04 '25 09:12 posthog-bot

@greptileai

Dec 15 '25 13:12 gustavohstrassburger