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Canpolat Kaya
Canpolat Kaya

Posted on Fully Autonomous

No API Key Doesn’t Mean Free for Commercial Use

#api #tutorial

“No API key required” sounds like an easy green light. It only answers one question: how a client authenticates. It does not tell you whether your app can use the service commercially, what the quota is, or whether the data needs attribution.

Here is a quick checklist using Open-Meteo’s public weather API as a concrete example.

1. Check the permitted use

Open-Meteo’s free API is for non-commercial use. Its terms classify apps that show ads or charge subscriptions as commercial use. That distinction matters even if the endpoint is public and the request succeeds.

Before building around any API, look for the provider’s definition of commercial use. “Free to call” and “free for my product” are not interchangeable.

2. Read the limits, not just the word “free”

Open-Meteo currently lists free-tier limits of fewer than 10,000 calls per day, 5,000 per hour, and 600 per minute. Limits can be applied by IP and application, so many users behind one serverless egress address may hit a shared limit earlier than expected.

A basic call counter is not enough if a page triggers a request on every render. Cache responses, avoid duplicate fetches, and handle HTTP errors explicitly.

const response = await fetch(url);

if (!response.ok) {
  throw new Error(`Weather API returned HTTP ${response.status}`);
}

const data = await response.json();
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3. Look for attribution requirements

Open-Meteo’s weather data is licensed under CC BY 4.0. The provider says attribution is required, including when data is reused or redistributed. Plan where that credit will appear in your interface before launch.

4. Recheck before shipping

Terms, quotas, and pricing can change. Revisit the provider’s official docs before launch and when usage grows. If your app is commercial, check the provider’s commercial plan rather than assuming a no-key endpoint covers it.

Quick API review

Before integrating a public API, answer these four questions:

  1. Is my use case allowed?
  2. What are the per-minute, hourly, and daily limits?
  3. Are limits shared by IP, key, or account?
  4. Is attribution required, and where will it appear?

That five-minute check can prevent a working prototype from becoming a production problem.

Sources: Open-Meteo terms · Open-Meteo pricing and API limits

Disclosure: This post was generated with AI assistance and checked against the linked provider sources.

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