Backfill
Domains Wikipedia still points to.
English Wikipedia links out to the rest of the web tens of thousands of times, and some of those links now point at domains that no longer exist, sit parked, or were never re-registered after they lapsed. Backfill tracks them: it harvests the live external links from English Wikipedia (not archive.org links), checks each registrable domain against its registry (RDAP) and against DNS, and publishes the result as an index and an API.
On this page: the API · the house-ads manager
The index as of 2026-10-23
| Class | Domains |
|---|---|
| available — no registry record found when checked | 267 |
| registered-live-dns — registered, with DNS resolving | 158103 |
| parked — registered and parked | 2570 |
| registered-no-dns — registered, but nothing in DNS | 2321 |
| unknown — the checks were inconclusive | 1321 |
| restricted — | 298 |
| Total tracked | 164880 |
Classes are what the checks found on the date above: available means the registry returned no record for the name; parked means the name is registered and parked; the rest are registered in various states of use. The source data is an English Wikipedia external-links harvest, registry RDAP lookups, and DNS-over-HTTPS checks.
Available, and still linked from Wikipedia
A sample of the unregistered domains in the index, ordered by how many Wikipedia links point to them. The article names link to the Wikipedia pages carrying the links. The complete unregistered list is part of the dataset — see the API below.
| Domain | Linked from |
|---|---|
| miak.or.kr | Lee Min-woo, Harisu, Harisu |
| montreal.qc.ca | Old Montreal, Place Jacques-Cartier, Boroughs of Montreal |
| postimg.org | |
| fpl.ua | Serhei Nudnyi, Bannikov Stadium |
| toronto.on.ca | Don Valley Parkway, Union Station (Toronto), Innovia Metro |
| searchindiannews.in | |
| cmd.or.ke | Westlands Constituency, Speaker of the National Assembly of Kenya, Mwingi North Constituency |
| bunge.go.ke | Beth Wambui Mugo, Elizabeth Ongoro |
| aux.tv | The alt.sessions, Michael Franti |
| avdigital.in | Manithanin Marupakkam, Rudraveena (film), Meendum Parasakthi |
The API
The index is available as JSON. Basic lookups are free; the two deep endpoints are paid per call through the x402 protocol — a request without payment receives a 402 response describing the payment (USDC on the Base network), and a request carrying a valid payment header is verified and settled through a facilitator, then served. No accounts, no keys.
| Endpoint | What it returns | Price |
|---|---|---|
| GET /api/v1/stats | Index date, counts by class, total | Free |
| GET /api/v1/domains?class=available&limit=10 | A sample of the domains in a class (at most 10 per call) | Free |
| GET /api/v1/domain/{name} | One domain: class, linking articles, DNS state | Free |
| GET /api/v1/domain/{name}/full | The basic record plus a live Wayback Machine summary (capture count, first and last captures) | $0.25 |
| GET /api/v1/firehose | The complete dataset, as published | $10.00 |
The free endpoints search the unregistered, parked, and unresolved portion of the index (4158 domains, bundled with this page). The complete index — all 164880 tracked domains — is the firehose dataset. Payment is per call in USDC on Base through x402: send a request, read the 402 response for the payment terms, pay, and resend with the payment header. No account or API key is involved.
House ads
Backfill began as a house-ads manager — a small tool that rotates a publisher's own links in their own ad slots and counts impressions and clicks without cookies. It still runs here: about the house-ads manager, with a live demo.
Domain status changes daily. An entry classed available means the registry had no record for it when checked — not a guarantee that it can be registered, or at what price. Verify availability at a registrar before relying on any entry. Data: English Wikipedia external-links dump (complete) + registry RDAP + DNS-over-HTTPS, as of 2026-10-23.