supabase/apps/docs/content/guides/functions/logging.mdx

---
id: 'functions-logging'
title: 'Logging'
description: 'How to access logs for your Edge Functions.'
subtitle: 'Monitor your Edge Functions with logging to track execution, debug issues, and optimize performance.'
---

Logs are provided for each function invocation, locally and in hosted environments.

---

## Accessing logs

### Production

Access logs from the Functions section of your Dashboard:

1. Navigate to the [Functions section](https://supabase.com/dashboard/project/_/functions) of the Dashboard
2. Select your function from the list
3. Choose your log view:
   - **Invocations:** Request/Response data including headers, body, status codes, and execution duration. Filter by date, time, or status code.
   - **Logs:** Platform events, uncaught exceptions, and custom log messages. Filter by timestamp, level, or message content.

![Function invocations.](/docs/img/guides/functions/function-logs.png)

### Development

When [developing locally](/docs/guides/functions/quickstart) you will see error messages and console log statements printed to your local terminal window.

---

## Log event types

### Automatic logs

Your functions automatically capture several types of events:

- **Uncaught exceptions**: Uncaught exceptions thrown by a function during execution are automatically logged. You can see the error message and stack trace in the Logs tool.
- **Custom log events**: You can use `console.log`, `console.error`, and `console.warn` in your code to emit custom log events. These events also appear in the Logs tool.
- **Boot and Shutdown Logs**: The Logs tool extends its coverage to include logs for the boot and shutdown of functions.

### Custom logs

You can add your own log messages using standard console methods:

```js
Deno.serve(async (req) => {
  try {
    const { name } = await req.json()

    if (!name) {
      // Log a warning message
      console.warn('Empty name parameter received')
    }

    // Log a message
    console.log(`Processing request for: ${name}`)

    const data = {
      message: `Hello ${name || 'Guest'}!`,
    }

    return new Response(JSON.stringify(data), {
      headers: { 'Content-Type': 'application/json' },
    })
  } catch (error) {
    // Log an error message
    console.error(`Request processing failed: ${error.message}`)
    return new Response(JSON.stringify({ error: 'Internal Server Error' }), {
      status: 500,
      headers: { 'Content-Type': 'application/json' },
    })
  }
})
```

<Admonition type="note">

A custom log message can contain up to 10,000 characters. A function can log up to 100 events within a 10 second period.

</Admonition>

---

## Logging tips

### Logging request headers

When debugging Edge Functions, a common mistake is to try to log headers to the developer console via code like this:

```ts index.ts
// ❌ This doesn't work as expected

Deno.serve(async (req) => {
  console.log(`Headers: ${JSON.stringify(req.headers)}`) // Outputs: "{}"
})
```

The `req.headers` object appears empty because Headers objects don't store data in enumerable JavaScript properties, making them opaque to `JSON.stringify()`.

Instead, you have to convert headers to a plain object first, for example using `Object.fromEntries`.

```ts index.ts
// ✅ This works correctly
Deno.serve(async (req) => {
  const headersObject = Object.fromEntries(req.headers)
  const headersJson = JSON.stringify(headersObject, null, 2)

  console.log(`Request headers:\n${headersJson}`)
})
```

This results in something like:

```json
Request headers: {
    "accept": "*/*",
    "accept-encoding": "gzip",
    "authorization": "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZSIsInJlZiI6InN1cGFuYWNobyIsInJvbGUiOiJhbm9uIiwieW91IjoidmVyeSBzbmVha3ksIGh1aD8iLCJpYXQiOjE2NTQ1NDA5MTYsImV4cCI6MTk3MDExNjkxNn0.cwBbk2tq-fUcKF1S0jVKkOAG2FIQSID7Jjvff5Do99Y",
    "cdn-loop": "cloudflare; subreqs=1",
    "cf-ew-via": "15",
    "cf-ray": "8597a2fcc558a5d7-GRU",
    "cf-visitor": "{\"scheme\":\"https\"}",
    "cf-worker": "supabase.co",
    "content-length": "20",
    "content-type": "application/x-www-form-urlencoded",
    "host": "edge-runtime.supabase.com",
    "my-custom-header": "abcd",
    "user-agent": "curl/8.4.0",
    "x-deno-subhost": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiIsImtpZCI6InN1cGFiYXNlIn0.eyJkZXBsb3ltZW50X2lkIjoic3VwYW5hY2hvX2M1ZGQxMWFiLTFjYmUtNDA3NS1iNDAxLTY3ZTRlZGYxMjVjNV8wMDciLCJycGNfcm9vdCI6Imh0dHBzOi8vc3VwYWJhc2Utb3JpZ2luLmRlbm8uZGV2L3YwLyIsImV4cCI6MTcwODYxMDA4MiwiaWF0IjoxNzA4NjA5MTgyfQ.-fPid2kEeEM42QHxWeMxxv2lJHZRSkPL-EhSH0r_iV4",
    "x-forwarded-host": "edge-runtime.supabase.com",
    "x-forwarded-port": "443",
    "x-forwarded-proto": "https"
}
```