# Add annotations and metadata to segments with the X-Ray SDK for Node.js
<a name="xray-sdk-nodejs-segment"></a>

**Note**  
X-Ray SDK/Daemon Maintenance Notice – On February 25th, 2026, the AWS X-Ray SDKs/Daemon will enter maintenance mode, where AWS will limit X-Ray SDK and Daemon releases to address security issues only. For more information on the support timeline, see [X-Ray SDK and Daemon Support timeline](xray-sdk-daemon-timeline.md). We recommend to migrate to OpenTelemetry. For more information on migrating to OpenTelemetry, see [Migrating from X-Ray instrumentation to OpenTelemetry instrumentation ](https://docs.aws.amazon.com/xray/latest/devguide/xray-sdk-migration.html).

You can record additional information about requests, the environment, or your application with annotations and metadata. You can add annotations and metadata to the segments that the X-Ray SDK creates, or to custom subsegments that you create.

**Annotations** are key-value pairs with string, number, or Boolean values. Annotations are indexed for use with [filter expressions](xray-console-filters.md). Use annotations to record data that you want to use to group traces in the console, or when calling the [https://docs.aws.amazon.com/xray/latest/api/API_GetTraceSummaries.html](https://docs.aws.amazon.com/xray/latest/api/API_GetTraceSummaries.html) API.

**Metadata** are key-value pairs that can have values of any type, including objects and lists, but are not indexed for use with filter expressions. Use metadata to record additional data that you want stored in the trace but don't need to use with search.

In addition to annotations and metadata, you can also [record user ID strings](#xray-sdk-nodejs-segment-userid) on segments. User IDs are recorded in a separate field on segments and are indexed for use with search.

**Topics**
+ [Recording annotations with the X-Ray SDK for Node.js](#xray-sdk-nodejs-segment-annotations)
+ [Recording metadata with the X-Ray SDK for Node.js](#xray-sdk-nodejs-segment-metadata)
+ [Recording user IDs with the X-Ray SDK for Node.js](#xray-sdk-nodejs-segment-userid)

## Recording annotations with the X-Ray SDK for Node.js
<a name="xray-sdk-nodejs-segment-annotations"></a>

Use annotations to record information on segments or subsegments that you want indexed for search.

**Annotation Requirements**
+ **Keys** – The key for an X-Ray annotation can have up to 500 alphanumeric characters. You cannot use spaces or symbols other than a dot or period ( . )
+ **Values** – The value for an X-Ray annotation can have up to 1,000 Unicode characters.
+ The number of **Annotations** – You can use up to 50 annotations per trace.

**To record annotations**

1. Get a reference to the current segment or subsegment.

   ```
   var AWSXRay = require('aws-xray-sdk');
   ...
   var document = AWSXRay.getSegment();
   ```

1. Call `addAnnotation` with a String key, and a Boolean, Number, or String value.

   ```
   document.addAnnotation("mykey", "my value");
   ```

   The following example shows how to call `putAnnotation` with a String key that includes a dot, and a Boolean, Number, or String value.

   ```
   document.putAnnotation("testkey.test", "my value");
   ```

The SDK records annotations as key-value pairs in an `annotations` object in the segment document. Calling `addAnnotation` twice with the same key overwrites previously recorded values on the same segment or subsegment.

To find traces that have annotations with specific values, use the `annotation[key]` keyword in a [filter expression](xray-console-filters.md).

**Example app.js - annotations**  

```
var AWS = require('aws-sdk');
var AWSXRay = require('aws-xray-sdk');
var ddb = AWSXRay.captureAWSClient(new AWS.DynamoDB());
...
app.post('/signup', function(req, res) {
    var item = {
        'email': {'S': req.body.email},
        'name': {'S': req.body.name},
        'preview': {'S': req.body.previewAccess},
        'theme': {'S': req.body.theme}
    };

    var seg = AWSXRay.getSegment();
    seg.addAnnotation('theme', req.body.theme);
  
    ddb.putItem({
      'TableName': ddbTable,
      'Item': item,
      'Expected': { email: { Exists: false } }
  }, function(err, data) {
...
```

## Recording metadata with the X-Ray SDK for Node.js
<a name="xray-sdk-nodejs-segment-metadata"></a>

Use metadata to record information on segments or subsegments that you don't need indexed for search. Metadata values can be strings, numbers, Booleans, or any other object that can be serialized into a JSON object or array.

**To record metadata**

1. Get a reference to the current segment or subsegment.

   ```
   var AWSXRay = require('aws-xray-sdk');
   ...
   var document = AWSXRay.getSegment();
   ```

1. Call `addMetadata` with a string key, a Boolean, number, string, or object value, and a string namespace.

   ```
   document.addMetadata("my key", "my value", "my namespace");
   ```

   or

   Call `addMetadata` with just a key and value.

   ```
   document.addMetadata("my key", "my value");
   ```

If you don't specify a namespace, the SDK uses `default`. Calling `addMetadata` twice with the same key overwrites previously recorded values on the same segment or subsegment.

## Recording user IDs with the X-Ray SDK for Node.js
<a name="xray-sdk-nodejs-segment-userid"></a>

Record user IDs on request segments to identify the user who sent the request. This operation isn’t compatible with AWS Lambda functions because segments in Lambda environments are immutable. The `setUser` call can be applied only to segments, not subsegments.

**To record user IDs**

1. Get a reference to the current segment or subsegment.

   ```
   var AWSXRay = require('aws-xray-sdk');
   ...
   var document = AWSXRay.getSegment();
   ```

1. Call `setUser()` with a string ID of the user who sent the request.

   ```
   var user = 'john123';
   
   AWSXRay.getSegment().setUser(user);
   ```

You can call `setUser` to record the user ID as soon as your express application starts processing a request. If you will use the segment only to set the user ID, you can chain the calls in a single line.

**Example app.js - user ID**  

```
var AWS = require('aws-sdk');
var AWSXRay = require('aws-xray-sdk');
var uuidv4 = require('uuid/v4');
var ddb = AWSXRay.captureAWSClient(new AWS.DynamoDB());
...
    app.post('/signup', function(req, res) {
    var userId = uuidv4();
    var item = {
        'userId': {'S': userId},
        'email': {'S': req.body.email},
        'name': {'S': req.body.name}
    };

    var seg = AWSXRay.getSegment().setUser(userId);
  
    ddb.putItem({
      'TableName': ddbTable,
      'Item': item,
      'Expected': { email: { Exists: false } }
  }, function(err, data) {
...
```

To find traces for a user ID, use the `user` keyword in a [filter expression](https://docs.aws.amazon.com/xray/latest/devguide/xray-console-filters.html).