PostHog for VS Code

Feature flags, experiments, event analytics, and session replay — inline in your editor.

What it does

PostHog for VS Code brings your product analytics stack into the editor. See feature flag status, experiment results, event volumes, and session replay data right next to the code that uses them — no browser tab required.

Quick Start

1. Install the extension from the VS Code Marketplace
2. Sign in — open the PostHog sidebar (hedgehog icon in the activity bar) and authenticate with a personal API key (phx_...) or sign in with your PostHog account
3. Select your project when prompted
4. Done — the sidebar populates with your flags, experiments, and analytics. Inline decorations appear in your code automatically.

Features

Inline Code Intelligence

The core of the extension. Your PostHog data appears directly in your editor as you write code.

• Flag status decorations — see flag state inline after every flag call: ● enabled, ○ inactive, rollout %, variant count, or ⚠ not in PostHog
• Event volume and sparklines — 7-day event count and inline sparkline chart next to every capture() call
• Experiment results inline — flags linked to experiments show live status like ⚗ test leading 72%
• Variant code path highlighting — color-coded highlighting of if/else and switch branches behind experiment variants, with rollout percentages
• Flag key autocomplete — suggestions from your PostHog project inside isFeatureEnabled(', getFeatureFlag(', etc.
• Event name autocomplete — suggestions inside posthog.capture('
• Event property autocomplete — property names, types, and top values as you build event payloads
• Variant autocomplete — variant keys for multivariate flags
• Unknown flag detection — yellow wavy underline on flag keys that don't exist in PostHog, with a quick-fix to create them
• Event naming diagnostics — Levenshtein-based typo detection for event names that look similar to existing events
• Flag CodeLens — contextual actions above flag calls (open detail, view experiment)
• Session CodeLens — "X sessions / Y users in 24h" above capture and flag calls
• Cmd+click navigation — flag keys become links that open the flag or experiment detail panel

Sidebar Dashboard

A tabbed overview of your PostHog project, accessible from the activity bar.

• Flags tab — all feature flags with search, filter by status, toggle, and rollout editing
• Experiments tab — experiments with status indicators, results summary, and start/stop actions
• Analytics tab — saved insights from your PostHog project with auto-refresh
• "My Flags" filter — quickly show only flags you created
• Stale Flags tree view — dedicated tree view below the sidebar for codebase-wide flag hygiene

Flag Management

Create, toggle, and configure flags without leaving the editor.

• Toggle flags from code — code action with confirmation dialog
• Edit rollout %, variants, and payloads — full flag editor in a detail panel
• Create flags from unknown keys — quick-fix on unrecognized flag keys creates the flag in PostHog
• Generate TypeScript types — right-click context menu action to generate types from flag payload configurations
• Copy flag key — one-click copy to clipboard
• Open in PostHog — jump to the flag in the PostHog dashboard
• Wrap selection in flag — code action to wrap a code block in a feature flag check

Stale Flag Cleanup

Find and remove tech debt from shipped or abandoned flags.

• AST-based codebase scanning — finds all flag references across your project using tree-sitter
• 4 staleness categories — fully rolled out, inactive, experiment complete, not in PostHog
• Tree view — grouped by staleness reason, click to navigate to each reference
• Inline refactoring — code actions to remove flag checks and keep the correct code branch (handles if/else and ternary patterns)
• Batch cleanup — clean up all references for a stale flag at once
• Report export — export stale flag findings

Session Replay

Connect code to real user sessions.

• Session count CodeLens — see session and user counts above capture and flag calls
• Embedded replay — watch session recordings in detail panels without leaving VS Code

Team Configuration

Share PostHog settings across your team and manage multi-project workspaces.

• Shared .posthog.json config — commit project settings to your repo so the whole team connects automatically
• Multi-project workspace support — different workspace folders can target different PostHog projects
• RBAC awareness — read-only mode when your API key lacks write permissions
• Status bar indicator — shows active project, host, and last sync time. Click to switch projects.
• Periodic cache refresh — flags, events, and experiments stay in sync automatically

Commands

All commands are available via the Command Palette (Cmd+Shift+P / Ctrl+Shift+P):

Configuration

VS Code Settings

All settings live under posthog.* in VS Code settings (JSON or UI).

Code detection

Display

Stale flag detection

Workspace

Team Configuration (.posthog.json)

Share PostHog settings across your team by committing a .posthog.json file to your workspace root:

{
  "host": "https://us.posthog.com",
  "projectId": 12345,
  "additionalClientNames": ["analytics"],
  "additionalFlagFunctions": ["useMyFlag"]
}

When present, the extension loads this file on startup and merges the settings with your VS Code configuration. Each developer still authenticates individually with their own API key.

In a multi-root workspace, each folder can have its own .posthog.json targeting a different project — the extension detects project switches as you navigate between folders.

Supported Languages

Code intelligence (autocomplete, decorations, diagnostics, code actions) works in:

Powered by tree-sitter for accurate AST-based detection. Both client-side (posthog.capture('event')) and server-side (client.capture({ event: 'event' })) patterns are recognized.

Development

pnpm install          # install dependencies
pnpm compile          # webpack build
pnpm watch            # webpack watch mode
pnpm lint             # run eslint
pnpm test             # run tests
# Press F5 in VS Code to launch the Extension Development Host

Requirements

• VS Code 1.109.0 or later
• A PostHog account with a personal API key

Contributing

Contributions are welcome. Open an issue or pull request on GitHub.

License

MIT

Built by the PostHog community