Authentication & Pricing

API keys, pricing tiers, and usage limits

OpenAlex data is and will remain available at no cost. Our data snapshot is totally free for bulk download. The API is a freemium service with free daily usage—$0.10/day with no key, or 10× that ($1/day) with a free API key—and after that you pay for what you use. We sell services, not data.

Getting an API Key

To use the API at scale, you need a key. It’s free—just make an account (takes 30 seconds) and copy your key from openalex.org/settings/api. Then add api_key=YOUR_KEY to your API calls:

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

Costs

Pricing by Endpoint

Use per_page=100 to load many results per query—it makes your query budget go much further.

Operation	Description	Cost per 1,000 calls
Get singleton	Retrieve a single entity by ID or DOI	Free
List+Filter	Query and filter entities	$0.10
Search	Full-text keyword search	$1
Semantic search	AI-powered semantic search	$1
Content download	Cached PDF via content API	$10
Text/Aboutness (deprecated)	Topic classification	$10

The openalex.org website runs on this same API, so browsing it draws from the same budget (anonymous browsing uses the $0.10/day no-key budget; sign in for$1/day). Viewing a single record’s page (one work, author, source, etc.) is free, but a search or a results page loads several billable calls (the list of results plus its facets/charts).

One website search costs more than one API call. A single programmatic /works?search= call costs 10 credits, but one search on the website costs roughly 18 credits—the search itself plus ~5 facet/chart calls that fill the sidebar. So “$1/day ≈ 1,000 searches” holds for direct API calls; browsing the website is about 1.8× costlier per search (closer to ~550/day). A prepaid balance covers anything beyond your daily budget.

Common Activity Costs

Activity	Endpoint	Calls	Results	Cost
Search “climate change AND kelp”	Search	103	10,205	$0.10
All works from Harvard	List+Filter	8,707	870,627	$0.87
Retrieve works by DOI from a list	Singleton	1,000,000	1,000,000	Free
Daily research (20 searches, 200 filters, 50 lookups)	Mixed	270	~27,000	$0.04
Download 1,000 PDFs	Content	1,000	1,000 PDFs	$10.00

What You Can Do for Free Every Day

Your free API key gives you $1 of free usage every day. With that, you can do a mix of:

Action	Calls	Results	Example
Get a single entity	Unlimited	Unlimited	Look up a work by DOI
List+filter	10,000	1,000,000	All works from MIT in 2024
Search	1,000	100,000	Full-text search for “CRISPR”
Content download	100	100 PDFs	Download a paper’s full text

Without a key you get $0.10/day—a tenth of the above, enough to try the API. Get a free key for 10× the budget.

Increased Limits

Need more than $1/day? Paid plans give you higher daily allowances and prepaid usage.

Your daily budget refills every day at midnight UTC. A prepaid balance is a separate pool that automatically kicks in once your daily budget is spent for the day—buying prepaid credit doesn’t change your daily budget, it just covers usage beyond it (and doesn’t expire daily).

Keeping Tabs on Costs

Per Call

Rate Limit Headers

Every API response includes headers showing your current status:

Header	Description
X-RateLimit-Limit	Your total daily limit
X-RateLimit-Remaining	Remaining for today
X-RateLimit-Credits-Used	Cost of this request
X-RateLimit-Reset	Seconds until reset (midnight UTC)

Response Meta

Every response includes a meta object (see Response Format) with the cost of that request and the total result count, so you can estimate the cost of paginating through all results before committing:

"meta": {
  "count": 870627,
  "db_response_time_ms": 19,
  "page": 1,
  "per_page": 100,
  "groups_count": null,
  "cost_usd": 0.0001
}

Here, cost_usd tells you this call cost $0.0001 (list+filter calls are $0.10 per 1,000), and count tells you 870,627 results at 100 per page = 8,707 calls = $0.87 total.

Overall

Usage Dashboard

Check your usage anytime at openalex.org/settings/usage—accessible from the battery icon in the lower left of openalex.org.

Rate Limit Endpoint

You can also check programmatically via the /rate-limit endpoint:

curl "https://api.openalex.org/rate-limit?api_key=YOUR_KEY"

{
  "api_key": "abc...xyz",
  "rate_limit": {
    "daily_budget_usd": 1,
    "daily_used_usd": 0.05,
    "daily_remaining_usd": 0.95,
    "prepaid_balance_usd": 0,
    "prepaid_remaining_usd": 0,
    "prepaid_expires_at": null,
    "resets_at": "2026-02-20T00:00:00.000Z",
    "resets_in_seconds": 43200,
    "endpoint_costs_usd": {
      "singleton": 0,
      "list": 0.0001,
      "search": 0.001,
      "semantic": 0.01,
      "content": 0.01,
      "text": 0.01
    }
  }
}

Tips

Exceeding Limits

If you exceed your daily limit or make more than 100 requests per second, you’ll get 429 Too Many Requests errors.

Individual queries also have these constraints:

Limit	Value
OR values per filter	100
per_page maximum	100
sample maximum	10,000
Basic paging limit	10,000 results

To retrieve more than 10,000 results, use cursor paging.

Usage Tips

Best practices:

• Use per_page=100 to reduce the number of requests needed
• Batch ID lookups using the OR syntax (up to 100 values per filter)
• Use select= to limit returned fields for faster responses
• Implement exponential backoff when you hit rate limits

Browser testing: The API uses simple GET requests, so you can test any request in your browser. Install a JSON formatter extension for a better experience:

• JSONVue (Chrome)
• JSONView (Firefox)

Efficient bulk extraction:

# Use maximum page size
requests.get("https://api.openalex.org/works?per_page=100&api_key=YOUR_KEY")

# Batch DOI lookups (up to 100 at once)
dois = "10.1234/a|10.1234/b|10.1234/c"
requests.get(f"https://api.openalex.org/works?filter=doi:{dois}&api_key=YOUR_KEY")