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The CrossRef API
You count how many journal articles carry a word in their title, follow a DOI fingerprint to the page, and see what the registry gives free.
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The lesson
Trailer · 1:27
The challenge
The challenge asks for your field, not mine. Take the loudest claim in it, the one you keep hearing, and go and count it: one distinctive word, searched in titles only, with your own address on the courtesy line. Write your guess on paper before anything runs, let the registry settle it, and then follow by hand the fingerprint of the paper your field leans on hardest, to see whether the page opens or keeps you on this side of the glass. It needs no key and no payment; your AI writes the code and you read the fingerprints.
Starting points:
- A graduate student: count a term out of your thesis year by year, and notice when that field was born and whether it was born right behind a crisis.
- Someone who follows health news: take this week's public health word, ask for the most cited papers, and tell which abstracts the registry gives away and which cells come back empty.
- A tradesperson: count a word out of your own trade's regulations and follow the top fingerprint to the journal's page, to see what it withholds and what it gives away.
When you're done, tell us what you pursued and tell us what you got.
What you work with
Field Card · S01 · The CrossRef API
The distinction
The registry gives you every fingerprint and not every page. Having the number of a piece of work is one thing, and being allowed to read it is another thing entirely.
In practice
- Before anything runs, write your guess on paper and let the registry settle it.
- When an AI tells you the research on something is extensive, go and fetch the figure instead of taking the word.
- Read the AI's code whole: the word it actually searched, that it looked in titles and not everywhere, and that the address is yours.
- Follow one fingerprint by hand in a browser, and read what the page offers you before you scroll.
The question to keep asking
How much has science said about this, and can you read it?
The fine print
The address on the request is manners, not a key, and it authenticates nothing. Your own run will come back bigger than the board's count, because the registry grows while you sleep.
Glossary · S01 · The CrossRef API
- The fingerprint (DOI)
- A number that keeps pointing at the same piece of work forever, no matter who moves it, renames it, or decides one day to start charging for it. It has three parts: a block that says which publisher registered it, a slash, and whatever that publisher decided to call this one item. A fingerprint an AI invents resolves to nothing, and a real one resolves.
- The registry
- The one shared list that a group of publishers who compete for a living agreed to keep around the year two thousand, giving every item on it a permanent number. It holds the record of the pages and never the pages. It is a catalogue, not a library.
- The works endpoint
- The registry's door we hand the question to, and you can push on it without a badge and without paying anybody. Our sentence leaves as a plain web address, and what comes back is not a page but one figure, printed as text a machine can read.
- mailto
- The line that carries the address you sign the request with. It is manners, not a key: it moves you into the polite pool, where the people who said who they were get served first, and it authenticates nothing. An AI will write whatever address you give it, so the courtesy is yours to supply.
- The sleep
- The small wait between calls when the loop asks year by year. Nothing at this door compels it; it is there because the ask asked for it, and a shared registry is a shared road. An AI won't add that pause unless you ask.
- The most borrowed
- What a library knows about a book without opening it: how often it comes back to the desk. Here it is the sort by how often other papers have cited each one. The AI wrote the sort, and the world did the ranking, one citation at a time.
- The abstract
- The column some publishers send to the registry and some never do. Where it exists, the registry hands it over complete and for nothing; where it doesn't, the cell sits empty. It is the one column an AI was ever allowed to read.
- The resolver
- What you put in front of the fingerprint to follow it: paste the whole thing into any browser on earth and press return. The fingerprint decides where you go, not the search box, and it hands you off, publisher to publisher, onto the journal's own page.
- The closed page
- Not an empty room. The shelf is there, you can see the thing sitting on it, and there is a door that is sometimes locked. What it withholds is the argument, the method and the evidence; what it gives away is the claim.
References
Crossref. (2026). REST API, works endpoint.
Desinformación en tiempos de pandemia: tipología de los bulos sobre la Covid-19. (2020). El Profesional de la Información. DOI 10.3145/epi.2020.may.15.
Misinformation and its correction: Continued influence and successful debiasing. (2012). Psychological Science in the Public Interest. DOI 10.1177/1529100612451018.
Next: The arXiv API. Learn AI at TertulIA