# PostHog Emulator (service host)

Create an instance:
curl -s -X POST https://posthog.emulators.dev/_emulate/instances
# Hosted deployments create instances lazily when the returned URL is first used. The instance URL is a capability: anyone who has it can read and modify the instance, so save the returned URLs. Never store real secrets in an emulator.
# The server generates an unguessable name. An optional {"instance":"<prefix>"} body adds a readable prefix.

Then use the returned providerBaseUrl / controlBaseUrl. Example below uses a sample instance.
# PostHog Emulator

Stateful PostHog emulator focused on OpenAPI OAuth discovery, Client ID Metadata Document OAuth, projects, users, and events.

Provider base URL: https://posthog.your-instance.emulators.dev
Control base URL: https://posthog.your-instance.emulators.dev/_emulate

Supported surfaces:
- PostHog API: partial at /api
- PostHog OAuth 2.0: supported at /oauth

Control endpoints:
- https://posthog.your-instance.emulators.dev/_emulate/manifest
- https://posthog.your-instance.emulators.dev/_emulate/coverage
- https://posthog.your-instance.emulators.dev/_emulate/connections
- https://posthog.your-instance.emulators.dev/_emulate/state
- https://posthog.your-instance.emulators.dev/_emulate/ledger
- https://posthog.your-instance.emulators.dev/_emulate/faults
- POST https://posthog.your-instance.emulators.dev/_emulate/credentials
- POST https://posthog.your-instance.emulators.dev/_emulate/seed
- POST https://posthog.your-instance.emulators.dev/_emulate/reset

Fault injection:
Arm a one-shot provider failure with a glob pathPattern, then inspect /ledger for faulted: true.
curl -s -X POST https://posthog.your-instance.emulators.dev/_emulate/faults \
  -H "content-type: application/json" \
  -d '{"match":{"method":"GET","pathPattern":"/v1/*"},"response":{"status":503,"body":{"error":"temporary"}}}'

Connect:

## OpenAPI schema
POSTHOG_OPENAPI_URL=https://posthog.your-instance.emulators.dev/api/schema/

## OAuth metadata
POSTHOG_RESOURCE_METADATA_URL=https://posthog.your-instance.emulators.dev/.well-known/oauth-protected-resource

## Base URL (env)
POSTHOG_BASE_URL=https://posthog.your-instance.emulators.dev

## Create a credential
curl -s -X POST https://posthog.your-instance.emulators.dev/_emulate/credentials \
  -H "content-type: application/json" \
  -d '{"type":"bearer-token"}'

## Inspect requests
curl -s https://posthog.your-instance.emulators.dev/_emulate/ledger