I would take their displayed uptime with a huge grain of salt. The other day Claude Code and claude.ai web were completely unavailable for me (Claude Code got into logged out state and couldn’t even log in) for at least two hours, they showed hours of “elevated errors”, yet not a single minute of downtime was recorded. And then there was yet another outage finally with recorded downtime a few hours later…
Honestly my impression was the “nines” of reliability just means how many nines your reliability starts with, as a decimal. I never thought much about it though.
I will also say it’s amusing that the debate is between one and two nines. Neither is objectively great. If you built a system with >3.65 days of downtime in a year that wouldn’t be something you’d brag about in an interview.
I would take their displayed uptime with a huge grain of salt. The other day Claude Code and claude.ai web were completely unavailable for me (Claude Code got into logged out state and couldn’t even log in) for at least two hours, they showed hours of “elevated errors”, yet not a single minute of downtime was recorded. And then there was yet another outage finally with recorded downtime a few hours later…
Edit: This incident: https://status.claude.com/incidents/kyj825w6vxr8
It was 98.xx this morning when I posted.
This is pretty pedantic, but I think it's usually rounded. 1=90%, 2=99%, 3=99.9%. I'd say 98% is "not even two nines" but not "one nine".
Honestly my impression was the “nines” of reliability just means how many nines your reliability starts with, as a decimal. I never thought much about it though.
I will also say it’s amusing that the debate is between one and two nines. Neither is objectively great. If you built a system with >3.65 days of downtime in a year that wouldn’t be something you’d brag about in an interview.