web-archive
Perma.cc
A permanent-archiving service from the Harvard Library Innovation Lab, designed so links cited in legal and academic writing never rot; it holds millions of permalinks. Each archived page gets a short perma.cc code that replays the capture, and a free public API lets you look existing records up. Most useful when following a Perma link from a court document or paper, or when checking whether a page was preserved as a citation.
Why it’s useful & how it works
Perma.cc exists specifically to stop citation links from rotting in legal and academic writing. When a court, law journal, or scholar cites a web page, they can create a short perma.cc link that permanently replays that exact version of the page. A free public API lets you look up whether a given URL or Perma code already has a preserved record, making it useful for verifying citations found in court filings or articles. Echo links you to the public record for any Perma code it recognizes, so you can view the archived page directly.
What’s inside
Perma.cc has been adopted by hundreds of law journals and by courts filing thousands of briefs and opinions with Perma links since 2013. The service holds millions of permalinks; an exact public total is not published.
API access
Public read https://api.perma.cc/v1/public/archives/ (no key) ; create needs API key. Replay https://perma.cc/ <code>.
What we measured
Our own probes, not the archive’s own claims. Re-run periodically; every reading below is dated.
Reachability
- Direct request
- Cloudflare challenge HTTP 403 1.4 s (just a moment)
- Through a datacenter proxy
- Cloudflare challenge HTTP 403 1.2 s (just a moment)
- API, direct
- Cloudflare challenge HTTP 403 519 ms (just a moment)
- API, through a proxy
- Cloudflare challenge HTTP 403 1.1 s (just a moment)
Did a real search return anything?
The request failed · median 10.8 s · down during the run
Slow: budget for long waits, or call it asynchronously.
HTTP 403 / 429 on every attempt (direct).
Reachability measured 2026-08-22. Search checked 2026-08-22.
Access
Programmatic API access (a key may be required, see the API tag).