ChatGPT API slowdown on 29 September 2026

ChatGPT API from Amsterdam, Mumbai, San Francisco, Singapore, Tokyo, Montreal: slower than usual; 2026-09-29 13:00 UTC to 2026-09-29 19:30 UTC: peak first visible token 3.39 s vs a usual 1.55 s.

What our checks saw: Slower than usual
Cities affected: Amsterdam, Mumbai, San Francisco, Singapore, Tokyo, Montreal
When: 29 Sept, 13:00 UTC to 29 Sept, 19:30 UTC
How long: 6.5 hours
Slowest check: 3.39 s, usually 1.55 s
OpenAI's status page: Open it

Where our checks saw it

Each glowing city had slow or failing checks during the incident, shown at its worst. We test from 6 cities, so other places may have been hit too.

Our checks, city by city

Each point is one check every 30 minutes, from three hours before the incident to three hours after. Coloured points are the checks we counted as slower or failing. The shaded area shows how far above the usual time they were.

Amsterdam

Each check (UTC)Usual (1.24 s)Slower than usualIncident

Every check as a table

Time (UTC)	Check	Reading
10:00	1.15 s	Normal
10:30	1.46 s	Normal
11:00	1.30 s	Normal
11:30	1.30 s	Normal
12:00	1.59 s	Normal
12:30	1.24 s	Normal
13:00	2.66 s	Slower than usual
13:30	2.01 s	Slower than usual
14:00	2.55 s	Slower than usual
14:30	1.12 s	Normal
15:00	1.75 s	Normal
15:30	2.97 s	Slower than usual
16:00	1.35 s	Normal
16:30	1.31 s	Normal
17:00	848 ms	Normal
17:30	1.35 s	No check
18:00	1.14 s	No check
18:30	1.08 s	Normal
19:00	891 ms	Normal
19:30	1.24 s	Normal
20:00	1.77 s	Normal
20:30	1.17 s	Normal
21:00	1.10 s	Normal
21:30	1.07 s	Normal
22:00	1.53 s	Normal
22:30	1.40 s	Normal

San Francisco

Each check (UTC)Usual (1.09 s)Slower than usualMuch slower, or failingSlow check outside the incidentIncident

Every check as a table

Time (UTC)	Check	Reading
10:00	1.36 s	Normal
10:30	1.17 s	Normal
11:00	1.81 s	Slower than usual
11:30	1.44 s	Normal
12:00	1.38 s	Normal
12:30	1.38 s	Normal
13:00	2.35 s	Slower than usual
13:30	1.62 s	Normal
14:00	3.25 s	Much slower, or failing
14:30	1.46 s	Normal
15:00	2.74 s	Much slower, or failing
15:30	1.57 s	Normal
16:00	1.69 s	Slower than usual
16:30	1.59 s	Normal
17:00	1.46 s	Normal
17:30	1.01 s	No check
18:00	1.10 s	No check
18:30	1.60 s	Normal
19:00	1.15 s	Normal
19:30	1.53 s	Normal
20:00	1.17 s	Normal
20:30	1.13 s	Normal
21:00	1.12 s	Normal
21:30	868 ms	Normal
22:00	1.05 s	Normal
22:30	1.11 s	Normal

Montreal

Each check (UTC)Usual (1.19 s)Slower than usualMuch slower, or failingSlow check outside the incidentIncident

Every check as a table

Time (UTC)	Check	Reading
10:00	1.46 s	Normal
10:30	1.23 s	Normal
11:00	1.32 s	Normal
11:30	1.66 s	Normal
12:00	1.59 s	Normal
12:30	1.96 s	Slower than usual
13:00	2.55 s	Slower than usual
13:30	1.91 s	Slower than usual
14:00	3.05 s	Much slower, or failing
14:30	1.44 s	Normal
15:00	2.64 s	Slower than usual
15:30	1.31 s	Normal
16:00	1.22 s	Normal
16:30	2.03 s	Slower than usual
17:00	873 ms	Normal
17:30	817 ms	No check
18:00	877 ms	No check
18:30	1.41 s	Normal
19:00	1.82 s	Slower than usual
19:30	983 ms	Normal
20:00	861 ms	Normal
20:30	845 ms	Normal
21:00	1.16 s	Normal
21:30	1.38 s	Normal
22:00	1.14 s	Normal
22:30	966 ms	Normal

Singapore

Each check (UTC)Usual (1.24 s)Slower than usualMuch slower, or failingSlow check outside the incidentIncident

Every check as a table

Time (UTC)	Check	Reading
10:00	1.64 s	Normal
10:30	1.37 s	Normal
11:00	1.09 s	Normal
11:30	969 ms	Normal
12:00	1.64 s	Normal
12:30	2.04 s	Slower than usual
13:00	2.52 s	Slower than usual
13:30	2.19 s	Slower than usual
14:00	3.29 s	Much slower, or failing
14:30	1.29 s	Normal
15:00	2.33 s	Slower than usual
15:30	1.27 s	Normal
16:00	1.48 s	Normal
16:30	1.27 s	Normal
17:00	1.38 s	Normal
17:30	898 ms	No check
18:00	1.22 s	No check
18:30	1.39 s	Normal
19:00	1.30 s	Normal
19:30	1.04 s	Normal
20:00	1.18 s	Normal
20:30	1.52 s	Normal
21:00	1.31 s	Normal
21:30	1.23 s	Normal
22:00	1.14 s	Normal
22:30	1.11 s	Normal

Tokyo

Each check (UTC)Usual (1.19 s)Slower than usualMuch slower, or failingSlow check outside the incidentIncident

Every check as a table

Time (UTC)	Check	Reading
10:00	1.19 s	Normal
10:30	1.10 s	Normal
11:00	1.86 s	Slower than usual
11:30	1.46 s	Normal
12:00	1.60 s	Normal
12:30	1.55 s	Normal
13:00	2.69 s	Slower than usual
13:30	1.36 s	Normal
14:00	2.98 s	Much slower, or failing
14:30	1.88 s	Slower than usual
15:00	1.40 s	Normal
15:30	1.56 s	Normal
16:00	1.45 s	Normal
16:30	1.60 s	Normal
17:00	1.40 s	Normal
17:30	1.13 s	No check
18:00	1.07 s	No check
18:30	1.74 s	Normal
19:00	1.17 s	Normal
19:30	1.45 s	Normal
20:00	1.13 s	Normal
20:30	946 ms	Normal
21:00	1.05 s	Normal
21:30	1.02 s	Normal
22:00	2.00 s	Slower than usual
22:30	1.20 s	Normal

Mumbai

Each check (UTC)Usual (1.55 s)Slower than usualMuch slower, or failingSlow check outside the incidentIncident

Every check as a table

Time (UTC)	Check	Reading
10:00	4.05 s	Much slower, or failing
10:30	1.30 s	Normal
11:00	1.43 s	Normal
11:30	1.57 s	Normal
12:00	2.28 s	Normal
12:30	2.65 s	Slower than usual
13:00	3.21 s	Slower than usual
13:30	2.53 s	Slower than usual
14:00	4.25 s	Much slower, or failing
14:30	1.43 s	Normal
15:00	2.44 s	Slower than usual
15:30	1.38 s	Normal
16:00	2.31 s	Normal
16:30	1.56 s	Normal
17:00	1.43 s	Normal
17:30	1.83 s	No check
18:00	1.64 s	No check
18:30	1.27 s	Normal
19:00	1.81 s	Normal
19:30	1.64 s	Normal
20:00	1.42 s	Normal
20:30	1.32 s	Normal
21:00	1.20 s	Normal
21:30	1.46 s	Normal
22:00	1.61 s	Normal
22:30	2.04 s	Normal

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