runtime-env-resolver

Overview

runtime-env-resolver lets you store environment variables as placeholders (e.g. ssm:/my/db/password) and resolve them at runtime from different sources such as AWS SSM Parameter Store, HashiCorp Vault, or your own custom provider.

✅ Keep secrets out of .env files
✅ Works with cloud & local environments
✅ Built-in support for AWS SSM (ssm: prefix)
✅ Extend with your own providers

Install

npm install runtime-env-resolver

Usage

1. Built-in Provider (AWS SSM)

(Requires @aws-sdk/client-ssm)

import { resolveEnvVariables, SSMProvider } from 'runtime-env-resolver';

// Works on AWS (Lambda, EC2) if IAM role has SSM permissions.
// For outside AWS: new SSMProvider({ region, credentials })
await resolveEnvVariables(new SSMProvider());

Before (process.env):

DB_PASSWORD=ssm:/myapp/db/password

After (process.env):

DB_PASSWORD=super-secure-password-from-ssm

2. Custom Provider

import { resolveEnvVariables } from 'runtime-env-resolver';

await resolveEnvVariables({
	shouldResolve(value) {
		return value.startsWith('custom:');
	},
	async resolve(values) {
		// Strip prefix
		const noPrefix = values.map((v) => v.replace('custom:', ''));

		// apply your own logic
		// NOTE: ensure to preserve order of values in the same order as the original array
		return noPrefix;
	},
});

Before (process.env):

DB_PASSWORD=custom:db-password-123

After (process.env):

DB_PASSWORD=db-password-123

Contributing

PRs and issues are welcome! Fork the repo and open a pull request.

License

MIT License – see LICENSE.

Resources

• NPM: https://www.npmjs.com/package/runtime-env-resolver
• GitHub: https://github.com/Maged-Zaki/runtime-env-resolver