Anubis Proof-of-Work Anti-Bot Challenge Blocks Content Access
Summary
BAILII (British and Irish Legal Information Institute) has deployed Anubis, a Proof-of-Work anti-bot system based on Hashcash principles, to protect its servers against automated scraping by AI companies. The system presents a computational challenge to reduce mass scraping while remaining negligible for individual legitimate users. The challenge page notes that JavaScript plugins like JShelter may interfere and should be disabled for the BAILII domain.
“This can and does cause downtime for the websites, which makes their resources inaccessible for everyone.”
About this source
BAILII, the British and Irish Legal Information Institute, is the open-access publisher of UK case law. The England and Wales Recent Decisions feed aggregates every newly published judgment from the High Court, Court of Appeal, and specialist divisions: Chancery, Commercial Court, Administrative Court, Family, Patents, Technology and Construction. Around 200 published opinions a month. BAILII is the closest thing to a free Westlaw for UK judgments and the standard citation source for academic and practitioner work that does not have a paid database licence. GovPing tracks each new decision as it appears, with the case name, court, judge, and citation. Watch this if you brief English commercial litigation, follow Chancery and TCC trends, or research UK judgments from outside a paid platform.
What changed
BAILII has added Anubis, a Proof-of-Work anti-bot challenge system, to its public-facing infrastructure. The system requires visiting browsers to solve a computational puzzle before accessing case content, with the stated goal of making mass automated scraping economically impractical. Individual human users experience the challenge as negligible latency, while bulk scrapers face compounding computational cost. The implementation uses a Hashcash-style proof-of-work mechanism. Users of JavaScript control plugins such as JShelter may need to disable those extensions for the BAILII domain to ensure the challenge executes correctly. This is an operational security measure for BAILII's infrastructure, not a legal or regulatory instrument affecting third parties.
For legal researchers and practitioners relying on BAILII for case law access: the challenge should resolve transparently in standard browsers without manual intervention. Users who employ anti-fingerprinting or JavaScript-blocking extensions should whitelist BAILII to ensure uninterrupted access to England and Wales decisions.
Archived snapshot
Apr 23, 2026GovPing captured this document from the original source. If the source has since changed or been removed, this is the text as it existed at that time.
Making sure you're not a bot!
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You are seeing this because the administrator of this website has set up Anubis to protect the server against the scourge of AI companies aggressively scraping websites. This can and does cause downtime for the websites, which makes their resources inaccessible for everyone.
Anubis is a compromise. Anubis uses a Proof-of-Work scheme in the vein of Hashcash, a proposed proof-of-work scheme for reducing email spam. The idea is that at individual scales the additional load is ignorable, but at mass scraper levels it adds up and makes scraping much more expensive.
Ultimately, this is a placeholder solution so that more time can be spent on fingerprinting and identifying headless browsers (EG: via how they do font rendering) so that the challenge proof of work page doesn't need to be presented to users that are much more likely to be legitimate.
Please note that Anubis requires the use of modern JavaScript features that plugins like JShelter will disable. Please disable JShelter or other such plugins for this domain.
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Source document text, dates, docket IDs, and authority are extracted directly from BAILII.
The summary, classification, recommended actions, deadlines, and penalty information are AI-generated from the original text and may contain errors. Always verify against the source document.
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