Smartsheet Authentication: Methods & Security Best Practices (2026)

Authentication overview

Smartsheet provides programmatic access to its platform through its API, enabling developers to integrate Smartsheet with other applications, automate workflows, and manage data. Effective authentication is critical for securing these interactions, ensuring that only authorized users and applications can access or modify Smartsheet resources. The Smartsheet API primarily utilizes two authentication methods: Personal Access Tokens (PATs) for direct user-based API access and OAuth 2.0 for applications requiring delegated access on behalf of users.

Understanding the appropriate authentication method for specific integration scenarios is crucial for maintaining security and operational efficiency. Personal Access Tokens are suitable for scripting and personal integrations where an application acts on behalf of a single user. OAuth 2.0 is designed for broader application integrations, allowing users to grant consent for an application to access their Smartsheet data without sharing their primary credentials. Both methods are designed to protect user data and ensure secure API interactions, aligning with industry-standard security practices for API access control, as detailed by the IETF OAuth 2.0 framework documentation.

Supported authentication methods

Smartsheet supports two main authentication methods for its API, each designed for different integration use cases:

• Personal Access Tokens (PATs): These are long-lived tokens generated by a user within their Smartsheet account. A PAT grants the same permissions as the user who generated it. They are typically used for scripts, command-line tools, and server-side applications that perform actions on behalf of a single user. PATs are sensitive credentials and should be treated with the same level of security as a password.
• OAuth 2.0: This open standard provides a secure way for third-party applications to obtain limited access to a user's Smartsheet account without ever exposing the user's login credentials. OAuth 2.0 is ideal for applications that need to access Smartsheet on behalf of multiple users, offering a consent-based authorization flow. Smartsheet implements the authorization code grant type, which is recommended for web applications requiring secure access. The OAuth 2.0 specification is widely adopted for secure delegated authorization.

The choice between PATs and OAuth 2.0 depends on the application's nature and its requirements for user interaction and scope of access.

Getting your credentials

To authenticate with the Smartsheet API, you will need to obtain appropriate credentials based on your chosen authentication method.

For Personal Access Tokens (PATs):

1. Log in to your Smartsheet account.
2. Click on the profile icon in the bottom-left corner and select Apps & Integrations.
3. Navigate to API Access and then Generate new access token.
4. Provide a name for your token and confirm.
5. Copy the generated token immediately. It will only be displayed once. Store it securely, as you will not be able to retrieve it again.

For more detailed step-by-step instructions, refer to the Smartsheet API access token creation guide.

For OAuth 2.0:

To use OAuth 2.0, you must register your application with Smartsheet to obtain a Client ID and Client Secret. These credentials identify your application to Smartsheet's authorization server.

1. Go to the Smartsheet Developer Portal.
2. Register a new application, providing details such as your application name, description, and importantly, the Redirect URI(s). The Redirect URI is where Smartsheet will send the user back after they authorize your application, along with an authorization code.
3. Upon successful registration, you will be provided with a Client ID and a Client Secret. The Client Secret should be kept confidential and never exposed in client-side code.
4. Implement the OAuth 2.0 authorization flow in your application. This involves directing users to Smartsheet's authorization endpoint, handling the callback at your Redirect URI, exchanging the authorization code for an access token and refresh token, and then using the access token to make API calls.

The Smartsheet developer documentation provides comprehensive guides on implementing OAuth 2.0 with Smartsheet, including details on scopes and token management.

Authenticated request example

Once you have your credentials, you can make authenticated requests to the Smartsheet API. Both PATs and OAuth 2.0 access tokens are typically passed in the Authorization header using the Bearer scheme.

Using a Personal Access Token (PAT):

Here's an example using curl to list all sheets accessible by the user associated with the PAT:

curl -X GET \
  'https://api.smartsheet.com/2.0/sheets' \
  -H 'Authorization: Bearer YOUR_PERSONAL_ACCESS_TOKEN' \
  -H 'Content-Type: application/json'

Replace YOUR_PERSONAL_ACCESS_TOKEN with your actual PAT.

Using an OAuth 2.0 Access Token:

After completing the OAuth 2.0 flow and obtaining an access token, you can use it similarly:

curl -X GET \
  'https://api.smartsheet.com/2.0/users/me' \
  -H 'Authorization: Bearer YOUR_OAUTH_ACCESS_TOKEN' \
  -H 'Content-Type: application/json'

This example fetches information about the currently authenticated user. Replace YOUR_OAUTH_ACCESS_TOKEN with the access token obtained through the OAuth flow. Remember that OAuth access tokens have a limited lifespan and should be refreshed using the refresh token before they expire, as outlined in the AWS Cognito documentation on token endpoint usage which details token refresh mechanisms.

Security best practices

Implementing strong security practices is essential when integrating with the Smartsheet API to protect sensitive data and prevent unauthorized access.

• Secure Storage of Credentials:
  • Never hardcode API keys or personal access tokens directly into your source code.
  • Store PATs and OAuth Client Secrets in environment variables, secure configuration files, or a dedicated secrets management service (e.g., AWS Secrets Manager, Azure Key Vault).
  • Restrict access to these storage locations to only authorized personnel and systems.
• Least Privilege Principle:
  • When creating a Personal Access Token, ensure the associated Smartsheet user has only the minimum necessary permissions required for the integration to function.
  • For OAuth 2.0 applications, request the narrowest possible set of API scopes from users. This limits the potential impact if your access token is compromised.
• Token Rotation and Expiration:
  • Regularly rotate Personal Access Tokens. While PATs are long-lived, periodic rotation reduces the risk associated with a compromised token.
  • For OAuth 2.0, leverage refresh tokens to obtain new access tokens. Ensure refresh tokens are also securely stored and managed. Implement mechanisms to handle token expiration and refresh failures gracefully.
• Error Handling and Logging:
  • Implement robust error handling to prevent sensitive information from being exposed in error messages.
  • Log authentication attempts and failures. Monitor these logs for suspicious activity, such as repeated failed login attempts or unusual API access patterns.
• Secure Communication:
  • Always use HTTPS for all API communications. The Smartsheet API strictly enforces HTTPS to ensure data is encrypted in transit.
  • Validate SSL/TLS certificates to prevent man-in-the-middle attacks.
• Input Validation:
  • Sanitize and validate all input and output when interacting with the Smartsheet API to prevent injection attacks and ensure data integrity.
• Auditing and Monitoring:
  • Regularly audit user and application permissions within Smartsheet.
  • Monitor API usage for anomalies that could indicate a security breach. Smartsheet provides event reporting features to help track user and API activities.