Rate limits and authentication

The API uses a credit-based rate limiting system. Different endpoint types consume different amounts of credits per request.

Credit costs by endpoint type

Endpoint Type	Example	Credits per Request
Singleton	/works/W123, /works/W123/ngrams	1
List	/works?filter=..., /autocomplete/works	10
Content	content.openalex.org/works/{id}.pdf	100
Vector	Vector searches (future)	1,000
Text (Aboutness)	/text/topics?title=...	1,000

High-cost endpoints

Some endpoints consume significantly more credits than standard queries:

Endpoint	Credits	Daily limit (free)	Notes
Content downloads	100	~1,000 files	PDF or TEI XML
Aboutness (/text)	1,000	~100 requests	Topic classification
Vector search	1,000	~100 requests	Coming soon

Planning bulk content downloads? Downloading all 60M available PDFs would require 6 billion credits. Contact us about enterprise credit packs for large-scale projects.

Rate limits

Starting February 13, 2026, an API key is required to use the OpenAlex API. API keys are free—get yours here. See the announcement for details.

The limits are:

• Without an API key: 100 credits per day (for testing and demos only)

• With a free API key: 100,000 credits per day

• All users: max 100 requests per second (regardless of credit cost)

For example, with 100,000 credits you can make:

• 100,000 singleton requests (like /works/W123), or

• 10,000 list requests (like /works?filter=type:article), or

• Any combination that adds up to 100,000 credits

If you exceed your daily credits or make more than 100 requests per second, you'll get 429 errors instead of useful data.

Need higher limits? Subscribe to OpenAlex Premium for significantly more credits per day. Academic researchers can often get increased limits for free—contact [email protected].

Are you scrolling through a list of entities, calling the API for each? You can go way faster by squishing 50 requests into one using our OR syntax. Here's a tutorial showing how.

Rate limit headers

Every API response includes headers showing your current rate limit status:

Header	Description
X-RateLimit-Limit	Your total daily credit limit
X-RateLimit-Remaining	Credits remaining for today
X-RateLimit-Credits-Used	Credits consumed by this request
X-RateLimit-Reset	Seconds until your credits reset (midnight UTC)

Check your rate limit status

You can check your current rate limit status at any time using the /rate-limit endpoint (requires an API key):

GET https://api.openalex.org/rate-limit?api_key=YOUR_API_KEY

Response:

{
  "api_key": "abc...xyz",
  "rate_limit": {
    "credits_limit": 100000,
    "credits_used": 1234,
    "credits_remaining": 98766,
    "resets_at": "2024-01-02T00:00:00.000Z",
    "resets_in_seconds": 43200,
    "credit_costs": {
      "singleton": 1,
      "list": 10,
      "content": 100,
      "vector": 1000,
      "text": 1000
    }
  }
}

Authentication

An API key is required to use the OpenAlex API. The good news: API keys are free! Here's how to get one:

1. Create a free account at openalex.org

2. Go to openalex.org/settings/api to get your key

3. Add api_key=YOUR_KEY to your API calls

Example:

• https://api.openalex.org/works?api_key=YOUR_KEY

Without an API key, you're limited to just 100 credits per day—enough for quick tests, but not for real work. With a free API key, you get 100,000 credits per day.

Premium users get even higher limits and access to special filters like from_updated_date.

Usage tips

Calling the API in your browser

Because the API is all GET requests without fancy authentication, you can view any request in your browser. This is a very useful and pleasant way to explore the API and debug scripts; we use it all the time.

However, this is much nicer if you install an extension to pretty-print the JSON; JSONVue (Chrome) and JSONView (Firefox) are popular, free choices. Here's what an API response looks like with one of these extensions enabled:

A lot prettier than cURL