> ## Documentation Index
> Fetch the complete documentation index at: https://docs.apinizer.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Log

> You can capture the current message state at any point in the API Proxy message pipeline and send it to selected connectors. This policy enables mid-pipeline snapshot logging across HTTP, WebSocket, and gRPC protocols.

<Tip>
  This document describes the detailed usage of a specific policy. If you are using the Apinizer policy structure for the first time or want to learn the general operating principles of policies, we recommend reading the [What is Policy?](/en/concepts/core-concepts/what-is-policy) page first.
</Tip>

## Overview

### Purpose

* The Log Policy captures a **snapshot of the current message state** at any point in the message processing pipeline and sends it to designated connectors.
* Unlike standard traffic logging, it enables logging at intermediate points in the pipeline (e.g., before and after a transformation policy) to track message changes.
* Works across HTTP, WebSocket, and gRPC protocols.
* Can send to multiple connectors simultaneously.

### How It Works

1. **Policy Trigger**: The policy executes when its turn comes in the message processing pipeline.
2. **Snapshot Creation**: The current message state is captured in a protocol-specific manner (headers, parameters, body).
3. **Connector Delivery**: The snapshot is sent to each defined connector individually.
4. **Privacy Application**: If privacy settings are enabled, sensitive data is processed before delivery (masking, deletion, hashing, encryption).

## Features and Capabilities

### Core Features

* **Sync/Async Execution**: In synchronous mode, the pipeline waits until delivery is complete; in asynchronous mode, the pipeline continues while delivery happens in the background.
* **Multi-Protocol Support**: Works across HTTP, WebSocket, and gRPC protocols.
* **Multi-Connector Delivery**: The same snapshot can be sent to multiple connectors.
* **Field-Level Control**: Headers, parameters, body, metadata, and metrics can each be independently enabled or disabled.
* **Body Size Limiting**: Body data can be logged fully or partially. In partial mode, a maximum size can be specified.
* **Policy-Level Privacy**: Masking, deletion, hashing, or encryption can be applied to sensitive data.
* **Condition-Based Execution**: Define conditions to ensure the policy only runs in specific situations.

### Protocol Support

| Protocol      | Header | Parameter | Body |
| ------------- | :----: | :-------: | :--: |
| **HTTP**      |    ✓   |     ✓     |   ✓  |
| **WebSocket** |    ✓   |     —     |   ✓  |
| **gRPC**      |    —   |     —     |   ✓  |

<Info>
  Header and parameter information may be limited in WebSocket and gRPC protocols due to their protocol structure.
</Info>

## Configuration Fields

<img src="https://mintcdn.com/apinizer/bgom9mCEH0MbSei2/images/develop/politikalar/log-1.png?fit=max&auto=format&n=bgom9mCEH0MbSei2&q=85&s=73bd4abd1a58abe188486d3e22206cf8" alt="log" width="1000" data-path="images/develop/politikalar/log-1.png" />

### General Settings

| Field          | Description                                                         |
| -------------- | ------------------------------------------------------------------- |
| Name           | Descriptive name of the policy                                      |
| Description    | Description explaining the purpose of the policy                    |
| Active         | Active/inactive status of the policy                                |
| Execution Mode | **Synchronous** or **Asynchronous** execution mode (detailed below) |
| Condition      | Condition determining when the policy executes (optional)           |

### Connector Selection

You can select the connectors to which the policy will send logs. Connectors are selected through connection definitions and work independently of environments — the same connection definition may correspond to different connector instances in different environments.

<img src="https://mintcdn.com/apinizer/bgom9mCEH0MbSei2/images/develop/politikalar/log-2.png?fit=max&auto=format&n=bgom9mCEH0MbSei2&q=85&s=8c447462e1fc9180a8acadbc67591a0c" alt="log" width="1000" data-path="images/develop/politikalar/log-2.png" />

<Info>
  A log policy defined as a global policy works across all environments. In each environment, the connector corresponding to the relevant connection definition is automatically matched.
</Info>

### Logged Fields

You can determine which of the following field groups are included in the log record:

| Field Group                    | Description                                                   |
| ------------------------------ | ------------------------------------------------------------- |
| Request Headers from Client    | Request header information from client to API Proxy           |
| Request Parameters from Client | Request parameters from client to API Proxy                   |
| Request Body from Client       | Request body from client to API Proxy                         |
| Request Headers to Target      | Request header information sent from API Proxy to Backend API |
| Request Parameters to Target   | Request parameters sent from API Proxy to Backend API         |
| Request Body to Target         | Request body sent from API Proxy to Backend API               |
| Response Headers from Target   | Response header information from Backend API                  |
| Response Body from Target      | Response body from Backend API                                |
| Response Headers to Client     | Response header information sent to client                    |
| Response Body to Client        | Response body sent to client                                  |
| Metadata                       | Request metadata such as IP address, HTTP method, URI, port   |
| Metrics                        | Performance metrics such as duration, size, cache status      |

### Body Logging Mode

| Mode    | Description                                                                                       |
| ------- | ------------------------------------------------------------------------------------------------- |
| Full    | Body data is logged completely                                                                    |
| Partial | Body data is logged up to the specified maximum size. Data is truncated when the size is exceeded |

### Privacy Settings

<img src="https://mintcdn.com/apinizer/bgom9mCEH0MbSei2/images/develop/politikalar/log-3.png?fit=max&auto=format&n=bgom9mCEH0MbSei2&q=85&s=c5bcac382d62a8cc72923e90ee666fa1" alt="log" width="1000" data-path="images/develop/politikalar/log-3.png" />

You can configure privacy settings at the policy level to process sensitive data before it is written to the log record.

| Operation | Description                                       |
| --------- | ------------------------------------------------- |
| Mask      | Partially hides sensitive data (e.g., `****1234`) |
| Delete    | Completely removes sensitive data                 |
| Hash      | Converts sensitive data to a one-way hash value   |
| Encrypt   | Encrypts sensitive data                           |

<Info>
  Privacy settings are applied at two levels: first the policy-level settings, then the connector-level settings. If both levels are enabled, both are applied in sequence.
</Info>

## Sync and Async Execution

| Mode                      | Delivery                         | Error Behavior              | Pipeline Impact        |
| ------------------------- | -------------------------------- | --------------------------- | ---------------------- |
| **Synchronous** (default) | Sequential, waits for completion | Error is thrown             | Pipeline **breaks**    |
| **Asynchronous**          | Background, non-blocking         | Error is logged, suppressed | Pipeline **continues** |

<Warning>
  In synchronous mode, a connector error breaks the pipeline and returns an error to the client. If uninterrupted operation is required in production, prefer **asynchronous** mode.
</Warning>

<Tip>
  In asynchronous mode, when a connector error occurs, the error information is written to application logs, but the client request is not affected.
</Tip>

## Use Cases

| Scenario                           | Description                                                                               | Recommended Mode |
| ---------------------------------- | ----------------------------------------------------------------------------------------- | ---------------- |
| Pre/post transformation comparison | Add log policies before and after a transformation policy to track message changes        | Async            |
| Debugging                          | Add a temporary log point to the pipeline to inspect a specific policy's input and output | Sync             |
| Audit trail                        | Maintain a complete record of every request to sensitive APIs                             | Async            |
| Multi-target logging               | Send the same message to Elasticsearch and Kafka simultaneously                           | Async            |
| Conditional logging                | Log only requests matching a specific header value or path                                | Async            |

## Related Pages

* [Message Flow and Policy Management](/en/develop/policies/message-flow-and-policy-management)
* [API Proxy Traffic Log Settings](/en/develop/api-proxy-configuration/api-traffic-log-settings)
* [Connectors](/en/integrations/connectors/overview)
* [Adding Connectors to Gateway Environments](/en/admin/server-management/adding-connectors-to-gateway-environments)

## Next Steps

<CardGroup cols={2}>
  <Card title="Script Policy" icon="code" href="/en/develop/policies/script">
    Custom data transformation with scripts
  </Card>

  <Card title="API Call Policy" icon="arrow-right-arrow-left" href="/en/develop/policies/api-call">
    External API calls within the pipeline
  </Card>
</CardGroup>