Hebrew Calendar Authentication: API Key Setup & Security (2026)

Authentication overview

Authentication for the Hebrew Calendar Developer API is primarily managed through API keys. This method allows developers to access the various endpoints for retrieving Jewish calendar dates, holiday information, and other related data. API keys are unique identifiers assigned to a user or application, enabling the Hebcal service to verify the origin and authorization level of incoming requests. This approach simplifies the integration process for developers while providing a foundational layer of security.

When an API key is included in a request, the Hebcal server checks its validity and permissions before processing the request. This mechanism is suitable for applications requiring read-only access to public data, where the primary concern is identifying the requesting application rather than individual user identity. For personal and non-commercial use, access to the API is free, which typically involves obtaining a basic API key to ensure proper usage tracking and prevent abuse. Commercial or enterprise applications often require custom licensing and may involve more stringent authentication or rate limiting, though the underlying API key mechanism remains consistent for identifying the client application.

The use of API keys aligns with common practices for public APIs that provide data access without requiring user-specific authorization flows like OAuth 2.0. While OAuth 2.0 provides delegated authorization for specific user data, API keys are effective for authenticating the application itself, ensuring that only registered and approved applications consume the service. Developers should understand the scope of their API key and adhere to usage policies outlined in the Hebcal developer documentation to avoid service interruptions or account restrictions.

Supported authentication methods

The Hebrew Calendar API primarily supports authentication via API keys. This is a straightforward method where a unique key is provided with each API request to identify the client application. The key is typically passed as a query parameter in the URL of the API endpoint.

Below is a table summarizing the supported authentication method:

It is important to note that API keys, when exposed in client-side code, should be restricted in their permissions or protected by domain whitelisting if the API provider supports it. For the Hebrew Calendar API, given its read-only nature for public Jewish calendar data, the risk associated with API key exposure is generally lower compared to APIs handling sensitive user information. However, proper handling is still advised to prevent unauthorized consumption of API quotas or potential abuse.

Other authentication methods, such as OAuth 2.0 or mutual TLS, are not documented as primary authentication mechanisms for the standard Hebcal Developer API. These methods are typically employed by APIs that require user consent for accessing personal data or for high-security, enterprise-level integrations with stringent identity verification requirements. The Hebcal API's focus on providing public-facing calendar data makes API keys a pragmatic and efficient choice for most developers, adhering to a common pattern for API key authentication in cloud services like Google Cloud.

Getting your credentials

To obtain an API key for the Hebrew Calendar API, developers need to follow a registration process on the Hebcal website. While specific step-by-step instructions for API key generation are typically found within the developer documentation or an account dashboard, the general procedure involves creating an account and requesting a key.

1. Visit the Hebcal Developer API page: Navigate to the developer section on the official Hebcal website. This page serves as the central hub for all API-related information, including documentation and access instructions.
2. Account Registration: If you do not already have one, you will likely need to register for a user account. This typically involves providing an email address and creating a password. Account creation helps Hebcal manage API usage and provide support.
3. Request an API Key: Once logged in, there should be a dedicated section or link to generate or request an API key. This process might be automated, generating a key instantly, or it might require a brief review by the Hebcal team, especially for commercial or high-volume usage requests.
4. Review Terms of Service: During the key acquisition process, thoroughly read and understand the Hebcal API's terms of service and usage policies. This will outline any rate limits, acceptable use guidelines, and commercial licensing requirements. For personal and non-commercial use, the API is generally free, but specific terms will apply.
5. Store Your Key Securely: Once your API key is generated, it is crucial to store it securely. Treat it like a password. Do not hardcode it directly into publicly accessible client-side code without appropriate precautions, and consider environment variables or secure configuration management for server-side applications.

For enterprise or commercial applications, contact the Hebcal team directly through their website for custom pricing and potentially different credentialing processes that might involve service agreements or higher usage quotas. The Hebcal developer resources will provide the most up-to-date information on obtaining and managing your API credentials.

Authenticated request example

To make an authenticated request to the Hebrew Calendar API, you simply append your API key as a query parameter to the API endpoint URL. This example demonstrates how to request today's Hebrew date and parsha using a hypothetical API key.

Consider an endpoint for a daily Jewish calendar feed. A typical request might look like this:

GET https://www.hebcal.com/converter/?cfg=json&gy=2026&gm=5&gd=29&g2h=1&api_key=YOUR_API_KEY

In this example:

• https://www.hebcal.com/converter/ is the base URL for the converter API.
• ?cfg=json&gy=2026&gm=5&gd=29&g2h=1 are standard parameters for requesting a conversion from Gregorian date May 29, 2026, to the Hebrew date, configured for JSON output.
• &api_key=YOUR_API_KEY is where you insert your actual API key, which authenticates your request.

Here's a JavaScript example using the fetch API to make a request:

const API_KEY = 'YOUR_ACTUAL_API_KEY'; // Replace with your obtained API key
const GREGORIAN_YEAR = 2026;
const GREGORIAN_MONTH = 5;
const GREGORIAN_DAY = 29;

const apiUrl = `https://www.hebcal.com/converter/?cfg=json&gy=${GREGORIAN_YEAR}&gm=${GREGORIAN_MONTH}&gd=${GREGORIAN_DAY}&g2h=1&api_key=${API_KEY}`;

fetch(apiUrl)
  .then(response => {
    if (!response.ok) {
      throw new Error(`HTTP error! status: ${response.status}`);
    }
    return response.json();
  })
  .then(data => {
    console.log('Hebrew Date Data:', data);
    // Process the Hebrew date data, e.g., display it on a webpage
    const hebrewDate = data.hebrew;
    const parsha = data.parsha;
    document.getElementById('hebrew-date-display').innerText = 
      `Hebrew Date: ${hebrewDate}, Parsha: ${parsha}`;
  })
  .catch(error => {
    console.error('Error fetching Hebrew date:', error);
    document.getElementById('hebrew-date-display').innerText = 
      'Failed to load Hebrew date.';
  });

// Assuming you have an HTML element like: <div id="hebrew-date-display"></div>

This JavaScript snippet demonstrates how to construct the URL with the API key and handle the response. For server-side languages like Python or PHP, similar principles apply, where you concatenate the API key into the request URL before sending it. Always replace YOUR_ACTUAL_API_KEY with the key you received from Hebcal.

Security best practices

While API keys offer a straightforward authentication mechanism for the Hebrew Calendar API, adopting best practices is essential to protect your credentials and maintain the integrity of your applications. Following these guidelines helps prevent unauthorized access and potential misuse of your API quota.

1. Do Not Expose Keys in Client-Side Code Without Restrictions: If your application runs entirely in a web browser, avoid embedding your API key directly into publicly accessible JavaScript files. While the Hebcal API primarily offers read-only public data, exposing the key can lead to unauthorized usage against your quota. If client-side requests are necessary, consider proxying them through your own secure backend or utilizing domain restrictions if Hebcal provides such features for its API keys.
2. Use Environment Variables for Server-Side Applications: For server-side applications (e.g., Node.js, Python, PHP backends), store your API key in environment variables rather than hardcoding it directly into your source code. This practice prevents the key from being committed to version control systems like Git and keeps it separate from your application logic. For example, in a Node.js application, you might access the key via process.env.HEBCAL_API_KEY.
3. Implement Least Privilege: While Hebcal API keys generally have broad read access, if there were ever a hierarchy of keys or permissions, always request and use the key with the minimum necessary privileges for your application's functionality. This limits the damage if a key is compromised.
4. Rotate API Keys Regularly: Periodically generating a new API key and revoking the old one is a good security habit. This practice reduces the window of opportunity for a compromised key to be exploited. Check your Hebcal account dashboard or developer portal for options to rotate keys.
5. Monitor API Usage: Regularly review your API usage statistics, if available through your Hebcal account. Unusual spikes in requests or activity from unexpected locations could indicate a compromised key. Early detection allows you to revoke the key and investigate quickly.
6. Secure Your Development Environment: Ensure that your development machines and build systems are secure. Malicious software or insecure configurations can expose API keys stored locally or during deployment processes. Use strong passwords, two-factor authentication for developer accounts, and keep systems patched.
7. Understand Rate Limits and Usage Policies: Familiarize yourself with the Hebcal API's rate limits and usage policies. While not strictly a security measure, adhering to these prevents your key from being flagged or temporarily blocked due to excessive requests, which could be misinterpreted as malicious activity. Using appropriate caching mechanisms can also help reduce the number of direct API calls, staying within limits.

By implementing these security best practices, developers can ensure that their integration with the Hebrew Calendar API remains secure and efficient, protecting both their application and the service provider's infrastructure. These recommendations are consistent with general API security best practices for managing credentials.