What ARK is¶
An ARK (Archival Resource Key) is a persistent identifier that looks like this:
It sits on plain HTTP and DNS. That single fact separates it from DOI and Handle, and most of what follows comes from it.
ARK is not a peer of DOI and Handle¶
This is the part people get wrong, so it is worth stating plainly.
flowchart TB
subgraph H["Handle System (CNRI / DONA)"]
DOI["10.xxxx — DOI<br/><small>registration agencies manage the namespace;<br/>records live with the RA</small>"]
HDL["20.500.xxxxx — CNRI Handle<br/><small>a prefix an organisation buys</small>"]
end
ARK["ark:/99999/…<br/><small>plain HTTP and DNS. No substructure beneath it.</small>"]DOI is built on Handle. doi.org is a Handle resolver, and a DOI is a name in
Handle's 10.x namespace. ARK alone is a separate lineage — nothing sits beneath
it that has to be bought, joined or operated by someone else.
The three differences that matter¶
It is free, and the namespace is free. A NAAN costs nothing and is granted by the ARK Alliance. There is no registration agency to pay and no membership to maintain.
Nobody guarantees persistence on your behalf. With a DOI, the registration agency is part of the promise. With an ARK, the promise is yours and you say what it is — which is why the scheme has a way to ask:
erc:
who: 山田太郎
what: A dataset
when: 2026
where: https://repo.example.ac.jp/records/1
policy: NP | NR, OP, CC | 2026 | https://example.org/policy
commitment-level: permanent-dynamic
An identifier that claims nothing is worth less than one that says exactly what it claims. ARK makes the claim explicit and checkable rather than implied by a logo.
It can name anything, at any granularity. A dataset, a page of a manuscript, a physical specimen, a concept. There is no requirement that the thing be online, or even that it exist any more — the resolver can still return a description (FAIR A2).
The promise the design turns on¶
ARK declares NR — no re-assignment. A name, once given out, never comes to mean something else.
That one commitment is why arkhe:
- has no delete for an ARK or for a namespace,
- refuses to move a shoulder back out of
retired, - makes a primary key collision fail rather than quietly become an update,
- keeps resolving through mergers, splits and departures.
Read Invariants for how each of those is enforced in code rather than left to discipline.
Terms¶
| NAAN | Name Assigning Authority Number. The 99999 part. Granted to an organisation |
| shoulder | A sub-namespace within a NAAN, such as /x9. What gets delegated to an organisation |
| blade | What follows the shoulder — the part that identifies the object |
| inflection | A ? or ?? suffix that asks the resolver about the identifier rather than following it |
| suffix passthrough | …/x9abc/page/3 resolves through the record for …/x9abc, so children need no identifiers of their own |
| NMA | Name Mapping Authority — whoever answers when the identifier is resolved |