---
sidebar_label: Lambda
doc_id: c2a37acc-5288-4024-9dc8-ca83f51bfb40
description: >-
Deploy and manage AWS Lambda functions across multiple regions with S3
replication and fine-grained concurrency control using nullplatform scopes.
keywords:
- AWS Lambda
- serverless
- multi-region deployment
- S3 replication
- nullplatform
- Concurrency
- Version-based provisioned concurrency
---
# Serverless functions running on AWS Lambda
## Overview
Nullplatform supports AWS Lambda as a target for serverless scopes.
When you define a scope with the **Serverless** target, it represents a specific AWS Lambda deployment environment with region-specific and execution-specific configuration.
You can define:
- **[Regional settings](#multi-region-deployment)**: Choose the AWS region where the function will be deployed and configure S3 replication for multi-region setups.
- **[Concurrency settings](#managing-concurrency-in-aws-lambda-scopes)**: Control how many executions can run simultaneously and whether the function should use provisioned capacity to minimize cold starts.
## Multi-region deployment
Deploying AWS Lambda functions across multiple regions requires additional configuration due to a key AWS constraint:
the S3 bucket hosting the deployment asset must reside in the **same region** as the Lambda function itself.
For example, a Lambda in `sa-east-1` (São Paulo) cannot access an asset stored in an S3 bucket located in `us-east-1` (Virginia).
To work around this limitation, you can use **S3 replication** and configure your **CI pipeline** to register separate
assets for each region within nullplatform.
### 1. Create a regional S3 bucket
Create a new S3 bucket in the *target region* where you want to deploy the Lambda function (e.g., `sa-east-1`).
### 2. Set up S3 replication
Configure S3 replication from the source bucket (e.g., `us-east-1`) to the newly created target bucket (e.g., `sa-east-1`).
> ℹ️ **Note:** See the [S3 Replication Walkthrough (AWS Docs)](https://docs.aws.amazon.com/AmazonS3/latest/userguide/replication-walkthrough1.html)
> for more information.
### 3. Extend your CI pipeline
Update your CI pipeline to:
- Fetch the current build
- Identify the original asset created in the source bucket
- Rewrite the asset URL to point to the replicated bucket
- Register a second asset in nullplatform, scoped for the target region
Here is a sample Bash script to automate this step:
```bash
#!/bin/bash
# Replace this with the name of the bucket in sa-east-1
replicated_bucket=replication_bucket_name
# Replace this with the name you want to identify the sa-east-1 asset in the nullplatform UI.
# We recommend using the name of the region so it is clear where it will be deployed.
replicated_asset_name=replication_asset
application_id=$(np application current --format json | jq -r '.id')
build=$(np build list --application_id "$application_id" --format json | jq -r 'first(.results[] | select(.status == "in_progress"))')
build_id=$(echo $build | jq '.id' -r)
original_asset=$(np asset list --build-id $build_id --format json | jq -r ".results[0]")
original_asset_path=$(echo $original_asset | jq -r ".url")
replicated_asset_path=$(echo "$original_asset_path" | sed -E "s#^(s3://)[^/]+#\1$replicated_bucket#")
np asset create --body "{
\"type\": \"lambda\",
\"url\": \"$replicated_asset_path\",
\"name\": \"$replicated_asset_name\",
\"build_id\": "$build_id",
\"application_id\": "$application_id",
\"metadata\":{}
}"
```
### 4. Configure AWS credentials and region via Providers
Use nullplatform’s provider configuration to ensure that each scope has the correct AWS credentials and region.
For example:
- Set production scopes to use `sa-east-1`
- Set development scopes to use `us-east-1`
> ℹ️ **Note:** See our docs for [configuring AWS as a provider](/docs/providers/supported-integrations/cloud-providers/aws-configuration).
### What it looks like in the UI
Once you’ve configured scopes for multi-region Lambda deployment, you’ll be able to select them in the **New Deployment** flow.
1. Go to **Deployments > + New Deployment**
2. Select the appropriate asset and scopes
3. You’ll see region-specific options for your Lambda scopes
## Managing concurrency in AWS Lambda scopes
Control how AWS Lambda handles concurrent executions for your serverless functions.
You can configure two types of concurrency:
- **Reserved concurrency**: Sets a fixed number of concurrent executions reserved for this function.
- **Provisioned concurrency**: Pre-warms a specific number of instances to reduce cold start latency.
Each type supports three configuration modes:
- **Managed** – Uses the concurrency settings managed at the organization level.
- **Custom value** – Allows you to define a specific concurrency value for this scope.
- **Non-provisioned / Use account limit** – Runs functions using the standard concurrency limits from your AWS account.
### Version-based concurrency management
Nullplatform uses **version-based provisioned concurrency**, since alias-based configurations are not compatible with blue/green deployments.
:::caution disable alias-based setups
If your function is currently configured with an **alias-based provisioned concurrency**, you must **disable it and redeploy** the scope.
:::
During deployment, nullplatform automatically provisions the new version. Once the blue/green rollout is complete, the previous version is cleaned up automatically.
> ℹ️ **Note**: Deployments with provisioned concurrency include an additional waiting step while AWS completes the provisioning process.
### How to enable concurrency settings
1. Go to **Development > Scopes** and click **+ Create scope** (or edit an existing one).
2. Expand the **Advanced** section and open the **Concurrency** tab.
3. Choose your configuration and save your changes.
