Understanding Akismet API Keys: How Many Sites Can One Key Protect?

One of the most common questions from users of the Akismet Anti-spam plugin is about API key usage. Specifically, website owners and developers often want to know if a single API key can be used across multiple websites or if a separate key is required for each site. This article clarifies how Akismet's API key system works for different types of plans and websites.

The Core Principle: One Key, Unlimited Sites

Based on information from support interactions, the fundamental rule is that a single Akismet API key can be used on an unlimited number of sites. This applies to both free (non-commercial) and paid (commercial) API keys. The key itself is not limited by the number of websites it is installed on.

What Determines the Right Plan? API Calls and Site Type

While the number of sites is unlimited, your subscription is governed by two main factors:

1. API Call Limit: Paid Akismet plans are capped by the total number of API calls (spam checks) made per month from all sites using that single key. As long as the combined traffic from every site using the key stays under your plan's monthly limit, you will not encounter issues. Exceeding this limit would require upgrading to a higher-tier plan.
2. Site Type and Commercial Use: This is the most critical distinction for choosing between a free and paid key.
   • Free Key (Non-Commercial): This key is strictly for personal, non-commercial sites only. According to the official documentation, if a site has advertising, sells products or services (e-commerce), solicits donations, uses affiliate links, or is related to a business, non-profit, or educational organization, it is not considered personal. Using a free key on such a site violates the Terms of Service.
   • Paid Key (Commercial): Any site that falls under the commercial umbrella outlined above requires a paid plan. A single paid key can cover all of your commercial sites, provided the total API calls remain under your subscription limit.

Common Scenarios and Solutions

Scenario 1: Multiple Personal Blogs

Problem: A user runs several personal blogs with no commercial activity and wants to know if they need multiple keys.
Solution: One free, non-commercial API key is sufficient for all personal blogs. The same key can be used on all sites.

Scenario 2: A Business with Multiple Client Sites

Problem: A developer manages websites for multiple clients, all of which are commercial.
Solution: The developer can use a single paid API key on all client sites. They must choose a paid plan (e.g., Plus, Enterprise) whose monthly API call limit accommodates the combined traffic from all protected sites. For developers with many clients, the Enterprise plan is often the most economical choice as it offers higher API call limits.

Scenario 3: A Non-Profit Organization Adding an Online Shop

Problem: A non-profit that was using a free key adds an e-commerce element to sell merchandise.
Solution: The moment the site engages in commercial activity like selling books, it no longer qualifies for a free key. The organization must purchase a paid plan. It is recommended that non-profits contact the Akismet team to inquire about potential special programs or reduced fees, as they may require documentation to verify non-profit status.

Key Takeaways

• You do not need a different API key for each website. A single key works everywhere.
• Your choice between a free or paid plan depends entirely on the commercial nature of your websites.
• Your required plan tier depends on the total volume of API calls generated by all sites using your key.
• Always ensure your site type aligns with your plan's terms to avoid service interruption.

For more specific details on API usage limits and plan comparisons, users can consult the official Akismet API usage documentation.