t.co
Mostly blocked
13 of the 16 URLs we have a verdict for under t.co are blocked in mainland China; 3 are not. The Great Firewall silently drops its packets so requests time out and poisons its DNS. 1,459 tests have been run under this domain since 2011-05-12, the most recent on 2026-04-20.
The two are filtered by different means — an unencrypted request by the address and keywords it carries in the clear, an encrypted one by the server name in its TLS handshake — so one working while the other does not is normal.
The site itself
http://t.coas of 2026Intermittenthttps://t.coas of 2026Blockedhttp://www.t.coas of 2026BlockedPages and subdomains (13)
http://t.co/l9ax1kitas of 2026Blockedhttp://t.co/iRxoYG32as of 2026Blockedhttp://t.co/FldwkorSas of 2026Intermittenthttp://t.co/6GLzV3qXas of 2026Blockedhttp://t.co/kpjIsxd6DCas of 2026Intermittenthttp://t.co/uBYUY7DzwLas of 2026Blockedhttp://t.co/Yz1dDuoLJ0as of 2026Blockedhttp://t.co/Eu9fcesYUias of 2026Blockedhttp://t.co/gBEVH0LHZwas of 2026Blockedhttp://t.co/FdyywbcbINas of 2026Blockedhttp://t.co/RBE2jD24n8as of 2026Blockedhttp://t.co/ISU3VFHHhPas of 2026Blockedhttps://t.co/wWBk63G3PIas of 2026BlockedAbout t.co and the Great Firewall
13 of the 16 URLs we have a verdict for under t.co are blocked in mainland China; 3 are not. The Great Firewall silently drops its packets so requests time out and poisons its DNS. 1,459 tests have been run under this domain since 2011-05-12, the most recent on 2026-04-20.
Plain HTTP and HTTPS differ here: http://t.co is intermittent, https://t.co is blocked. The two are filtered by different means — an unencrypted request by the address and keywords it carries in the clear, an encrypted one by the server name in its TLS handshake — so one working while the other does not is normal.
A VPN or another circumvention tool routes the request outside mainland China, past the filtering that blocks t.co. GreatFire runs GreatFire VPN; the Analyzer also tests the domains of many VPN and proxy providers, so you can check whether one is reachable before relying on it.
Elsewhere on the site
t.co is ranked #226 among the world's most-visited domains (Tranco).
Sites of similar popularity:nist.govbbc.co.ukuserapi.comubuntu.com
Each URL's status is its verdict over the last 90 days, the same one its own page headlines.