OpenAI's ChatGPT experienced a significant global outage on April 20, 2026, disrupting access for thousands of users worldwide and affecting related services like Codex, as confirmed by Downdetector spikes and OpenAI's status updates; this incident, lasting several hours, highlights ongoing infrastructure scaling challenges amid explosive demand for its large language model. Despite strong overall reliability—99.83% uptime for ChatGPT from January to April 2026—traders weigh historical patterns of peak-hour disruptions against OpenAI's massive compute investments and partnerships like those with Microsoft. Competitive pressures intensify scrutiny, with rivals like Anthropic reporting similar compute shortages. Key to watch: OpenAI's status.openai.com for elevated error rates and any Q2 earnings hints on capacity expansions, as usage surges could trigger further incidents before resolution deadlines.