4.1 Introduction to API Keys

API keys are one of the simplest and most widely used mechanisms for authenticating and authorizing API requests. An API key is a unique identifier assigned to a client application and is used to track and control access to an API.

What Are API Keys?

API keys are alphanumeric strings generated by API providers to uniquely identify and authenticate API consumers. They serve as a form of access control, allowing API providers to track API usage, enforce rate limits, and restrict access to specific endpoints.

API keys are typically sent in the header, query parameters, or request body when making an API request. Example request using an API key:

curl -H "Authorization: Api-Key YOUR_API_KEY" https://api.example.com/data

When to Use API Keys vs. OAuth 2.0

API keys and OAuth 2.0 are both common authentication methods, but they serve different purposes:

Feature	API Keys	OAuth 2.0
Purpose	Identifies the API client	Grants secure delegated access
Security Level	Moderate	High
Best Use Cases	Public and simple APIs	Secure user and server-to-server authentication
Token Expiry	Typically long-lived or permanent	Short-lived access tokens with refresh tokens
Access Control	Limited control; usually a single key per client	Fine-grained permissions using scopes and roles

Use API keys for simple authentication scenarios where security risks are low (e.g., rate-limited access to public APIs). Use OAuth 2.0 when handling sensitive user data, requiring granular permissions, or supporting multiple authentication flows.

Security Risks of API Keys

While API keys provide a straightforward authentication method, they have inherent security risks if not properly managed:

Exposure in Public Repositories: Hardcoded API keys in codebases or configuration files can be inadvertently exposed.
Unauthorized Use: If an API key is leaked, anyone with the key can access the API.
Lack of Granular Access Control: API keys often lack role-based access control (RBAC) or scope limitations.
Replay Attacks: Attackers can capture and reuse API keys if proper security mechanisms are not in place.

To mitigate these risks, organizations should implement API key management best practices, which are covered in later sections.

Real-World Scenarios: How API Keys Work in Practice

Use Case 1: Public Weather App Accessing a Read-Only API

Scenario

A mobile weather app fetches data from a public weather API using a unique API key provided upon registration.

Step-by-Step Breakdown API Key Generation

The app developer registers on the API provider's platform and receives an API key. Key Usage
The app sends requests with the API key in the header: Authorization: Api-Key YOUR_API_KEY. Access Control
The key is limited to read:forecast scope, restricting it to weather data only. Rate Limiting
The provider limits requests to 100 per hour per key to prevent abuse. 👉 Significance: API keys enable secure, rate-controlled access for public-facing apps without requiring user login.

Use Case 2: Internal Dashboard Querying Aggregated Metrics

Scenario

A company dashboard queries analytics data from an internal API using a backend-only API key for authentication.

Step-by-Step Breakdown API Key Registration

The dev team creates an API key through digiRunner’s Admin Console for the internal dashboard. Secure Key Handling
The key is stored securely in environment variables on the dashboard server. Permission Control
The key is restricted to read:metrics and has a short expiration window (24 hours). Monitoring
Usage logs are reviewed weekly to detect unusual traffic patterns. 👉 Significance: Internal systems benefit from scoped, expiring API keys managed securely via the gateway.

4.2 Managing API Keys in digiRunner

DigiRunner provides a centralized API security management system that allows developers to securely generate, distribute, and manage API keys.

API Key Management Principles

Avoid Using API Keys for User Authentication – API Keys should only be used to authenticate applications, not individual users.
Do Not Hardcode API Keys – Embedding API Keys in source code can lead to security risks.
Set an Expiration Date – Assign an expiration time to API Keys to limit long-term exposure.
Regularly Review and Revoke API Keys – Periodically audit API Key usage and revoke unnecessary keys.
Limit API Key Permissions – Apply the principle of least privilege when granting access.

Steps to Implement API Key Management in digiRunner

Access the API Key Management Page Log in to the digiRunner admin panel and navigate to the "Application Forms" section under "API Key." 🔗 API Key Management Guide
Apply for a New API Key Click "Apply for API Key," fill in the required application details, and submit the request. 🔗 Applying for API Key
Set API Key Expiration During the application process, you can define the API key’s expiration period to control its validity. 🔗 Obtaining API Keys and Calling APIs
Assign Permissions Specify the required access levels for the API key. 🔗 API Client Key Concepts
Approval Process The system will review the request according to the configured approval workflow. Once approved, the API key will be generated. 🔗 Approval Flow Settings
Monitor and Audit API Keys Regularly check API key usage and revoke or update keys as needed. 🔗 Monitoring and Auditing digiRunner Server

4.3 Best Practices for API Key Security

API keys must be protected to prevent unauthorized access and data breaches. Implementing the following security best practices ensures that API keys remain secure and properly managed.

1. Avoid Hardcoding API Keys

Why?

Exposing API keys in codebases increases the risk of credential leaks and unauthorized access.

How?

Store API keys in environment variables or secure vaults instead of hardcoding them.
Use configuration management tools to dynamically inject API keys when needed.
Leverage secret management solutions such as AWS Secrets Manager or HashiCorp Vault to securely store and retrieve API keys.

In digiRunner:

Implementation: API keys are generated and securely managed via the digiRunner Admin Console. Developers should avoid embedding keys in source code and use environment-based or vault-based storage instead.
Reference: Applying for API Key – Applying for API Key

2. Implement Key Scopes and Rate Limits

Why?

Applying granular access control ensures that API keys are restricted to the necessary permissions, minimizing potential damage in case of misuse.

How?

Scope-Based Access → Restrict API keys to specific endpoints and actions.
Role-Based Authorization → Assign permissions based on client roles to enforce least privilege access.
Rate Limiting → Set quotas per API key to prevent abuse and excessive API usage.

In digiRunner:

Implementation: When applying for an API Key in digiRunner, you can assign specific API scopes to control access permissions, and rate-limiting policies can be enforced to prevent misuse.
Reference:

🔹 API Scope – API Scope

🔹 Rate Limiting Policy – Rate Limiting Policy

3. Detect and Mitigate Key Abuse

Why?

Unauthorized access and misuse of API keys can lead to data breaches and security threats.

How?

Enable API logging to detect unauthorized access attempts.
Implement anomaly detection to identify unusual API call patterns (e.g., excessive requests in a short period).
Revoke compromised keys immediately to prevent further abuse.
Enforce regular key rotation to reduce the risk of long-term key exposure.

In digiRunner:

Implementation: digiRunner provides monitoring and tracking features under Observability modules, allowing administrators to detect unusual API key usage and revoke compromised keys.
Reference:

🔹 API Key Management – Managing API Keys in digiRunner

🔹 OnlineConsole – API real-time transaction track

By following these best practices, you can enhance API key security, minimize risks, and protect sensitive data from unauthorized access.

Conclusion

API key authentication remains a practical and lightweight method for securing API access, especially in scenarios where simplicity and performance are prioritized over complex authorization flows. Through this course, we've explored how API keys work, when to use them over OAuth 2.0, and the potential security risks if not managed properly.

To ensure long-term security and scalability, developers are encouraged to adopt best practices such as avoiding hardcoded keys, enforcing least-privilege permissions, and proactively monitoring usage patterns. When implemented correctly, API keys can be a secure and efficient part of your overall API security strategy.

By applying these insights in digiRunner, teams can build more secure, resilient, and well-governed API ecosystems.

digiRunner Playbook IV: API Key Authentication