# Send metrics using OpenTelemetry
<a name="metrics-otel-send"></a>

You can publish custom metrics to CloudWatch using the OpenTelemetry Protocol (OTLP). You can use OTel SDKs (Java, Python, Go, .NET, Node.js), the OTel Collector, or any OTLP-compatible client.

## CloudWatch OTLP endpoint
<a name="metrics-otel-send-endpoint"></a>

Send metrics to the CloudWatch OTLP endpoint in your Region:

```
https://monitoring.{{region}}.amazonaws.com/v1/metrics
```

Authentication uses standard Amazon SigV4 signing. The service name is `monitoring`. For more information about the endpoint, authentication options, and limits, see [OTLP Endpoints](CloudWatch-OTLPEndpoint.md).

## Quick start: publish your first metric
<a name="metrics-otel-send-quickstart"></a>

### Option 1: OTel Collector (recommended for production)
<a name="metrics-otel-send-collector"></a>

Configure an OTel Collector with the OTLP HTTP exporter and SigV4 authentication:

```
receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318

processors:
  batch:
    send_batch_size: 200
    timeout: 10s

exporters:
  otlphttp:
    tls:
      insecure: false
    metrics_endpoint: "https://monitoring.{{us-east-1}}.amazonaws.com/v1/metrics"
    auth:
      authenticator: sigv4auth

extensions:
  sigv4auth:
    service: "monitoring"
    region: "{{us-east-1}}"

service:
  extensions: [sigv4auth]
  pipelines:
    metrics:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlphttp]
```

For detailed setup instructions, see [Getting started](CloudWatch-OTLPGettingStarted.md).

### Option 2: OTel SDK (Python example)
<a name="metrics-otel-send-python"></a>

```
from opentelemetry import metrics
from opentelemetry.sdk.metrics import MeterProvider
from opentelemetry.sdk.metrics.export import PeriodicExportingMetricReader
from opentelemetry.exporter.otlp.proto.http.metric_exporter import OTLPMetricExporter

# Point at the CloudWatch OTLP endpoint
exporter = OTLPMetricExporter(
    endpoint="https://monitoring.{{us-east-1}}.amazonaws.com:443/v1/metrics"
)
reader = PeriodicExportingMetricReader(exporter, export_interval_millis=60000)
provider = MeterProvider(metric_readers=[reader])
metrics.set_meter_provider(provider)

# Create and record a metric
meter = metrics.get_meter("my-app")
counter = meter.create_counter("http_requests_total", description="Total HTTP requests")
counter.add(1, {"method": "GET", "path": "/api/users", "status": "200"})
```

### Option 3: OTel SDK (Java example)
<a name="metrics-otel-send-java"></a>

```
import io.opentelemetry.api.metrics.Meter;
import io.opentelemetry.api.metrics.LongCounter;

Meter meter = GlobalOpenTelemetry.getMeter("my-app");
LongCounter counter = meter.counterBuilder("http_requests_total")
    .setDescription("Total HTTP requests")
    .build();

counter.add(1, Attributes.of(
    AttributeKey.stringKey("method"), "GET",
    AttributeKey.stringKey("path"), "/api/users",
    AttributeKey.stringKey("status"), "200"
));
```

## IAM permissions required
<a name="metrics-otel-send-iam"></a>

The identity sending metrics needs the `cloudwatch:PutMetricData` permission. For SigV4 authentication, attach the following policy:

```
{
  "Effect": "Allow",
  "Action": [
    "cloudwatch:PutMetricData"
  ],
  "Resource": "*"
}
```

For bearer token authentication, see [Setting up bearer token authentication for Metrics](CloudWatch-OTLP-MetricsBearerTokenAuth.md).

## Verify metrics are arriving
<a name="metrics-otel-send-verify"></a>

Open the CloudWatch console, navigate to **Query Studio**, and run:

```
http_requests_total
```

Metrics typically appear within 1–2 minutes of the first data point being sent.

## Supported metric types
<a name="metrics-otel-send-types"></a>

The following table describes the OTel metric types that CloudWatch supports and how to query them with PromQL.


| OTel metric type | PromQL behavior | 
| --- | --- | 
| Counter | Use rate() or increase() to query | 
| Gauge | Query directly (current value) | 
| Histogram | Use histogram\_quantile() for percentiles | 

## Best practices
<a name="metrics-otel-send-best-practices"></a>

Follow these recommendations when sending metrics through OTLP:
+ **Use meaningful metric names** — Follow OTel naming conventions (for example, `http.server.request.duration` or `http_request_duration_seconds`).
+ **Keep label cardinality reasonable** — Avoid request IDs or UUIDs as label values.
+ **Set an appropriate export interval** — 60 seconds is standard. Shorter intervals increase cost.
+ **Use resource attributes** — Use resource attributes for static metadata (service name, version, environment) rather than per-data-point labels.