PostHog

Server Source code Package

Server-side event delivery to PostHog for product analytics, identity resolution, group analytics, and feature flags via the official posthog-node SDK.

Where this fits

PostHog is a server destination in the walkerOS flow:

Sends events server-side to PostHog's ingestion API, translating walkerOS events into `capture`, `identify`, and `groupIdentify` calls with full control over identity and group resolution.

Installation

npm install @walkeros/server-destination-posthog

Integrated
Bundled

import { startFlow } from '@walkeros/collector';
import { destinationPostHog } from '@walkeros/server-destination-posthog';

await startFlow({
destinations: {
  posthog: {
    code: destinationPostHog,
    config: {
      settings: {
        apiKey: 'phc_XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX',
        host: 'https://eu.i.posthog.com',
      },
    },
  },
},
});

Add to your flow.json destinations:

"destinations": {
"posthog": {
  "package": "@walkeros/server-destination-posthog",
  "import": "destinationPostHog",
  "config": {
    "settings": {
      "apiKey": "phc_XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
      "host": "https://eu.i.posthog.com"
    }
  }
}
}

See bundled mode setup | CLI reference

Configuration

This destination uses the standard destination config wrapper (consent, data, env, id, ...). For the shared fields see destination configuration. Package-specific fields live under config.settings and are listed below.

Settings

Property	Type	Description
`apiKey*`	`string`	PostHog project API key (starts with "phc_"). Find it in PostHog project settings.
`host`	`string`	PostHog API host. Defaults to https://us.i.posthog.com. Use https://eu.i.posthog.com for EU or your self-hosted URL.
`flushAt`	`number`	Number of events queued before auto-flush. Default: 20.
`flushInterval`	`number`	Milliseconds between periodic flushes. Default: 10000.
`personalApiKey`	`string`	Personal API key (phx_...) for local feature flag evaluation.
`featureFlagsPollingInterval`	`number`	Milliseconds between feature flag definition polls. Default: 30000.
`disableGeoip`	`boolean`	Disable GeoIP lookups globally. Useful for GDPR compliance.
`debug`	`boolean`	Enable PostHog SDK debug logging. Default: false.
`identify`	`any`	walkerOS mapping value resolving to an identity object. Keys: distinctId, $set, $set_once. Resolved on every push (server is stateless).
`group`	`any`	walkerOS mapping value resolving to a group object. Keys: type, key, properties. Resolved on every push.
`include`	`Array<string>`	Event sections to flatten into capture() properties (e.g. ["data", "globals"]).

* Required fields

Mapping

Per-event rules under config.mapping. For the standard rule fields (consent, condition, data, batch, name, policy) see mapping.

Property	Type	Description	More
`identify`	`any`	Per-event identity mapping. Resolves to { distinctId, $set?, $set_once? }. Fires client.identify() when $set/$set_once present.
`group`	`any`	Group assignment. Resolves to { type, key, properties? }. Fires client.groupIdentify() when properties present, adds groups to capture().

Examples

Capture with group

A destination-level group mapping attaches the resolved group context to every PostHog capture call.

Event

{
  "name": "page view",
  "data": {
    "domain": "www.example.com",
    "title": "walkerOS documentation",
    "referrer": "https://www.walkeros.io/",
    "search": "?foo=bar",
    "hash": "#hash",
    "id": "/docs/"
  },
  "context": {
    "dev": [
      "test",
      1
    ]
  },
  "globals": {
    "pagegroup": "docs",
    "company_id": "company_123"
  },
  "custom": {
    "completely": "random"
  },
  "user": {
    "id": "us3r",
    "device": "c00k13",
    "session": "s3ss10n"
  },
  "nested": [
    {
      "entity": "child",
      "data": {
        "is": "subordinated"
      }
    }
  ],
  "consent": {
    "functional": true
  },
  "id": "0f8019ecc755c2de",
  "trigger": "load",
  "entity": "page",
  "action": "view",
  "timestamp": 1700000104,
  "timing": 3.14,
  "source": {
    "count": 1,
    "trace": "0a1b2c3d4e5f60718293a4b5c6d7e8f9",
    "type": "collector",
    "schema": "4"
  }
}

Out

client.capture({
  "distinctId": "us3r",
  "event": "page view",
  "properties": {},
  "groups": {
    "company": "company_123"
  }
})

Capture with include

Destination-level include flattens data and globals sections into prefixed PostHog event properties.

Event

{
  "name": "order complete",
  "data": {
    "id": "0rd3r1d",
    "currency": "EUR",
    "shipping": 5.22,
    "taxes": 73.76,
    "total": 555
  },
  "context": {
    "shopping": [
      "complete",
      0
    ]
  },
  "globals": {
    "pagegroup": "shop"
  },
  "custom": {
    "completely": "random"
  },
  "user": {
    "id": "us3r",
    "device": "c00k13",
    "session": "s3ss10n"
  },
  "nested": [
    {
      "entity": "product",
      "data": {
        "id": "ers",
        "name": "Everyday Ruck Snack",
        "color": "black",
        "size": "l",
        "price": 420
      },
      "context": {
        "shopping": [
          "complete",
          0
        ]
      },
      "nested": []
    },
    {
      "entity": "product",
      "data": {
        "id": "cc",
        "name": "Cool Cap",
        "size": "one size",
        "price": 42
      },
      "context": {
        "shopping": [
          "complete",
          0
        ]
      },
      "nested": []
    },
    {
      "entity": "gift",
      "data": {
        "name": "Surprise"
      },
      "context": {
        "shopping": [
          "complete",
          0
        ]
      },
      "nested": []
    }
  ],
  "consent": {
    "functional": true
  },
  "id": "09073abf930d0f48",
  "trigger": "load",
  "entity": "order",
  "action": "complete",
  "timestamp": 1700000101,
  "timing": 3.14,
  "source": {
    "count": 1,
    "trace": "0a1b2c3d4e5f60718293a4b5c6d7e8f9",
    "type": "collector",
    "schema": "4"
  }
}

Out

client.capture({
  "distinctId": "us3r",
  "event": "order complete",
  "properties": {
    "data_id": "0rd3r1d",
    "data_currency": "EUR",
    "data_shipping": 5.22,
    "data_taxes": 73.76,
    "data_total": 555,
    "globals_pagegroup": "shop"
  }
})

Consent granted

A walker consent command with analytics granted calls client.enable on the PostHog client.

Event

{
  "analytics": true
}

Out

client.enable()

Consent revoked

A walker consent command with analytics denied calls client.disable on the PostHog client.

Event

{
  "analytics": false
}

Out

client.enable();

client.disable()

Default capture

A walker event becomes a PostHog capture call with the user id as distinctId and no extra properties.

Event

{
  "name": "product view",
  "data": {
    "id": "ers",
    "name": "Everyday Ruck Snack",
    "color": "black",
    "size": "l",
    "price": 420
  },
  "context": {
    "shopping": [
      "detail",
      0
    ]
  },
  "globals": {
    "pagegroup": "shop"
  },
  "custom": {
    "completely": "random"
  },
  "user": {
    "id": "us3r",
    "device": "c00k13",
    "session": "s3ss10n"
  },
  "nested": [],
  "consent": {
    "functional": true
  },
  "id": "8730a13ed7b3a8f2",
  "trigger": "load",
  "entity": "product",
  "action": "view",
  "timestamp": 1700000100,
  "timing": 3.14,
  "source": {
    "count": 1,
    "trace": "0a1b2c3d4e5f60718293a4b5c6d7e8f9",
    "type": "collector",
    "schema": "4"
  }
}

Out

client.capture({
  "distinctId": "us3r",
  "event": "product view",
  "properties": {}
})

Group identify

A company update fires PostHog groupIdentify with group type, key, and associated group properties.

Event

{
  "name": "company update",
  "data": {
    "company_id": "company_123",
    "company_name": "Acme",
    "plan": "enterprise"
  },
  "context": {
    "dev": [
      "test",
      1
    ]
  },
  "globals": {
    "lang": "elb"
  },
  "custom": {
    "completely": "random"
  },
  "user": {
    "id": "us3r",
    "device": "c00k13",
    "session": "s3ss10n"
  },
  "nested": [
    {
      "entity": "child",
      "data": {
        "is": "subordinated"
      }
    }
  ],
  "consent": {
    "functional": true
  },
  "id": "dc910f7e333fd738",
  "trigger": "test",
  "entity": "company",
  "action": "update",
  "timestamp": 1700000103,
  "timing": 3.14,
  "source": {
    "count": 1,
    "trace": "0a1b2c3d4e5f60718293a4b5c6d7e8f9",
    "type": "collector",
    "schema": "4"
  }
}

Mapping

{
  "silent": true,
  "settings": {
    "group": {
      "map": {
        "type": {
          "value": "company"
        },
        "key": "data.company_id",
        "properties": {
          "map": {
            "name": "data.company_name",
            "plan": "data.plan"
          }
        }
      }
    }
  }
}

Out

client.groupIdentify({
  "groupType": "company",
  "groupKey": "company_123",
  "properties": {
    "name": "Acme",
    "plan": "enterprise"
  }
})

Identify with $set

A user login fires PostHog identify with $set and $set_once person properties and skips the capture.

Event

{
  "name": "user login",
  "data": {
    "user_id": "new-user-123",
    "email": "user@acme.com",
    "plan": "premium"
  },
  "context": {
    "dev": [
      "test",
      1
    ]
  },
  "globals": {
    "lang": "elb"
  },
  "custom": {
    "completely": "random"
  },
  "user": {
    "id": "us3r",
    "device": "c00k13",
    "session": "s3ss10n"
  },
  "nested": [
    {
      "entity": "child",
      "data": {
        "is": "subordinated"
      }
    }
  ],
  "consent": {
    "functional": true
  },
  "id": "198e984bcae96d14",
  "trigger": "test",
  "entity": "user",
  "action": "login",
  "timestamp": 1700000102,
  "timing": 3.14,
  "source": {
    "count": 1,
    "trace": "0a1b2c3d4e5f60718293a4b5c6d7e8f9",
    "type": "collector",
    "schema": "4"
  }
}

Mapping

{
  "silent": true,
  "settings": {
    "identify": {
      "map": {
        "distinctId": "data.user_id",
        "$set": {
          "map": {
            "email": "data.email",
            "plan": "data.plan"
          }
        },
        "$set_once": {
          "map": {
            "first_login": "timestamp"
          }
        }
      }
    }
  }
}

Out

client.identify({
  "distinctId": "new-user-123",
  "properties": {
    "$set": {
      "email": "user@acme.com",
      "plan": "premium"
    },
    "$set_once": {
      "first_login": 1700000102
    }
  }
})

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Installation​

Configuration​

Settings​

Mapping​

Examples

Capture with group

Capture with include

Consent granted

Consent revoked

Default capture

Group identify

Identify with $set

Installation

Configuration

Settings

Mapping