Connect to Amazon Web Services (AWS)

To understand how AWS supports OIDC, and for a detailed user guide on creating an OIDC identity provider with AWS, consult the AWS OIDC documentation.

1. Create an OIDC identity provider

   1. Navigate to the AWS Console
   2. Navigate to IAM then Identity Providers
   3. Select Add Provider
   4. Select OpenID Connect from the provider type
   5. Enter https://oidc.vercel.com in the Provider URL field
   6. Enter https://vercel.com/[TEAM_SLUG] in the Audience field, replacing [TEAM_SLUG] with the path from your Vercel team URL
   7. Select Add Provider

   

2. Create an IAM role

   To use AWS OIDC Federation you must have an IAM role. IAM roles require a "trust relationship" (also known as a "trust policy") that describes which "Principal(s)" are allowed to assume the role under certain "Condition(s)".

   Here is an example of a trust policy:

   trust-policy.json

   {
     "Version": "2012-10-17",
     "Statement": [
       {
         "Effect": "Allow",
         "Principal": {
           "Federated": "arn:aws:iam::[YOUR AWS ACCOUNT ID]:oidc-provider/oidc.vercel.com"
         },
         "Action": "sts:AssumeRoleWithWebIdentity",
         "Condition": {
           "StringEquals": {
             "oidc.vercel.com:sub": "owner:[TEAM SLUG]:project:[PROJECT NAME]:environment:production",
             "oidc.vercel.com:aud": "https://vercel.com/[TEAM SLUG]"
           }
         }
       }
     ]
   }

   The above policy's conditions are quite strict. It requires the aud sub sub claims to match exactly, but it's possible to configure less strict trust policies conditions:

   trust-policy.json

   {
     "Version": "2012-10-17",
     "Statement": [
       {
         "Effect": "Allow",
         "Principal": {
           "Federated": "arn:aws:iam::[YOUR AWS ACCOUNT ID]:oidc-provider/oidc.vercel.com"
         },
         "Action": "sts:AssumeRoleWithWebIdentity",
         "Condition": {
           "StringEquals": {
             "oidc.vercel.com:aud": "https://vercel.com/[TEAM SLUG]"
           },
           "StringLike": {
             "oidc.vercel.com:sub": [
               "owner:[TEAM SLUG]:project:*:environment:preview",
               "owner:[TEAM SLUG]:project:*:environment:production"
             ]
           }
         }
       }
     ]
   }

   This policy allows any project matched by the * that are targeted to preview and production but not development.

3. Define the role ARN as environment variable

   Once you have created the role, copy the role's ARN and declare it as an environment variable in your Vercel project with key name AWS_ROLE_ARN.

   .env.local

   AWS_ROLE_ARN=arn:aws:iam::accountid:user/username

   You are now ready to connect to your AWS resource in your project's code. Review the examples below.

In the following examples, you create a Vercel function in the Vercel project where you have defined the OIDC role ARN environment variable. The function will connect to a specific resource in your AWS backend using OIDC and perform a specific action using the AWS SDK.

Install the following packages:

pnpm i @aws-sdk/client-s3 @vercel/functions

In the API route for the function, use the AWS SDK for JavaScript to list objects in an S3 bucket with the following code:

import * as S3 from '@aws-sdk/client-s3';
import { awsCredentialsProvider } from '@vercel/functions/oidc';
 
const AWS_REGION = process.env.AWS_REGION!;
const AWS_ROLE_ARN = process.env.AWS_ROLE_ARN!;
const S3_BUCKET_NAME = process.env.S3_BUCKET_NAME!;
 
// Initialize the S3 Client
const s3client = new S3.S3Client({
  region: AWS_REGION,
  // Use the Vercel AWS SDK credentials provider
  credentials: awsCredentialsProvider({
    roleArn: AWS_ROLE_ARN,
  }),
});
 
export async function GET() {
  const result = await s3client.send(
    new S3.ListObjectsV2Command({
      Bucket: S3_BUCKET_NAME,
    }),
  );
  return result?.Contents?.map((object) => object.Key) ?? [];
}

Vercel sends the OIDC token to the SDK using the awsCredentialsProvider function from @vercel/functions.

Install the following packages:

pnpm i @aws-sdk/rds-signer @vercel/functions pg

In the API route for the function, use the AWS SDK for JavaScript to perform a database SELECT query from an AWS RDS instance with the following code:

import { awsCredentialsProvider } from '@vercel/functions/oidc';
import { Signer } from '@aws-sdk/rds-signer';
import { Pool } from 'pg';
 
const RDS_PORT = parseInt(process.env.RDS_PORT!);
const RDS_HOSTNAME = process.env.RDS_HOSTNAME!;
const RDS_DATABASE = process.env.RDS_DATABASE!;
const RDS_USERNAME = process.env.RDS_USERNAME!;
const RDS_CA_PEM = process.env.RDS_CA_PEM!;
const AWS_REGION = process.env.AWS_REGION!;
const AWS_ROLE_ARN = process.env.AWS_ROLE_ARN!;
 
// Initialize the RDS Signer
const signer = new Signer({
  // Use the Vercel AWS SDK credentials provider
  credentials: awsCredentialsProvider({
    roleArn: AWS_ROLE_ARN,
  }),
  region: AWS_REGION,
  port: RDS_PORT,
  hostname: RDS_HOSTNAME,
  username: RDS_USERNAME,
});
 
// Initialize the Postgres Pool
const pool = new Pool({
  password: signer.getAuthToken,
  user: RDS_USERNAME,
  host: RDS_HOSTNAME,
  database: RDS_DATABASE,
  port: RDS_PORT,
});
 
// Export the route handler
export async function GET() {
  try {
    const client = await pool.connect();
    const { rows } = await client.query('SELECT * FROM my_table');
    return Response.json(rows);
  } finally {
    client.release();
  }
}