A major Cloudflare outage on November 18, 2025, caused widespread disruptions across the internet, impacting numerous high-profile services including social media platform X (formerly Twitter), AI service ChatGPT, and many other websites relying on Cloudflare’s infrastructure. The outage originated from an unusual spike in traffic that caused internal service degradation and led to widespread server errors (HTTP 500), affecting Cloudflare’s content delivery network (CDN), DNS, and security services for its customers.
Services Most Affected by the Cloudflare Outage
The outage severely impacted multiple Cloudflare-provided services including:
- Core CDN and DNS services, essential for routing and loading websites.
- Popular online platforms such as X (formerly Twitter), OpenAI’s ChatGPT, Spotify, League of Legends, and Bet365 experienced downtime or degraded performance.
- Its Access and WARP services, which are used for VPN and zero-trust network access, were also disrupted but recovered earlier in the incident.
- Other Cloudflare offerings such as Workers, Dashboard access, and APIs faced errors or failures temporarily.
Cloudflare’s Response to the Unusual Traffic Spike
Cloudflare detected the spike of unusual traffic at approximately 11:20 UTC, which overwhelmed parts of its network leading to the outage. The company’s engineering team sprang into action to contain the issue and deployed a fix within a couple of hours. The immediate response involved:
- Implementing changes to restore critical services progressively.
- Re-enabling WARP access and reducing error rates on Access services.
- Continuing investigation post-restoration to understand the root cause and prevent recurrence.
- Commitment to publishing a detailed post-mortem after a full analysis is completed.
Impact on Websites Like ChatGPT and Twitter
Due to Cloudflare’s broad role in internet infrastructure, the outage caused:
- X (Twitter) users being unable to see or post tweets, with the platform largely inaccessible.
- ChatGPT users encountering errors and interruptions since the AI service relies on Cloudflare for routing traffic and security.
- Many other dependent websites served error 500 or were intermittently unreachable during the incident.
- Platforms like DownDetector, which monitors outages, were also affected, further complicating real-time reporting of the problem.
Timeline of Identification and Resolution
- The unusual traffic spike was identified around 11:20 UTC on November 18, 2025.
- Cloudflare confirmed the outage and started ongoing system status updates shortly after the spike.
- Engineers deployed fixes that restored critical services like WARP and Access by early afternoon UTC.
- Full recovery and normalization of other affected services occurred progressively during the day, with monitoring continuing thereafter.
Measures Taken to Prevent Future Outages
To mitigate the risks of similar incidents, Cloudflare is undertaking measures including:
- Thorough investigation into the root cause of the traffic spike and its origins.
- Enhancing traffic management and mitigation systems to handle unexpected spikes more gracefully.
- Improving monitoring and alerting to detect potential overloads earlier.
- Commitment to transparency by promising a comprehensive post-mortem report detailing lessons learned and infrastructure improvements.
- Reinforcement of security and resilience protocols for critical infrastructure components that affect broad swaths of internet traffic.
This outage highlights the critical role Cloudflare plays in the global internet ecosystem, where a single point of failure can ripple across many services. The company’s rapid response and ongoing commitment to transparency and prevention will be essential to restoring trust and improving resilience going forward.
