ChatGPT has revolutionized how millions of people work, learn, and create. But what happens when the world's most popular AI assistant suddenly goes dark? Whether you are a developer relying on the API, a business using ChatGPT for customer support, or simply someone who has grown accustomed to having an AI companion available 24/7, outages can be frustrating and even costly.
In this comprehensive guide, we will explore everything you need to know about ChatGPT outages: their history, causes, impact, and most importantly, what you can do when ChatGPT goes down. With over 120 million daily active users depending on this service, understanding its reliability has never been more critical.
Understanding ChatGPT Reliability: The State of AI Infrastructure
ChatGPT, launched in November 2022, has experienced phenomenal growth that has consistently pushed OpenAI's infrastructure to its limits. According to OpenAI's official status page, the service maintains approximately 99.3% uptime, which translates to roughly 5 hours of downtime per month on average. While this might sound acceptable for a consumer service, for businesses and developers who have integrated ChatGPT into their workflows, even brief outages can have significant consequences.
The reality is that AI infrastructure is fundamentally different from traditional web services. Large language models like GPT-4 and GPT-4o require massive computational resources, specifically thousands of high-performance GPUs working in concert. This creates unique challenges that traditional web applications simply do not face.
Sam Altman, CEO of OpenAI, has been remarkably candid about these challenges. In March 2025, he famously tweeted that the company's GPUs are melting due to overwhelming demand for ChatGPT's image generation features. This colorful description highlights the delicate balance OpenAI must maintain between meeting user demand and keeping their infrastructure stable.
Complete History of ChatGPT Outages: A Detailed Timeline
Understanding the history of ChatGPT outages helps us recognize patterns and prepare for future incidents. Here is a comprehensive timeline of every major outage since ChatGPT's launch.
2023: The Early Days
In the first year of ChatGPT's existence, outages were relatively rare but significant when they occurred.
March 20, 2023: The Security Shutdown
The first major outage occurred on March 20, 2023, when OpenAI completely shut down ChatGPT for approximately 4 hours due to a critical security vulnerability. This was not a typical infrastructure failure but rather an emergency response to a serious bug in the redis-py library.
The vulnerability exposed user data in alarming ways. During a 9-hour window between 1 AM and 10 AM Pacific time, some users could see fragments of other users' chat histories. Even more concerning, approximately 1.2% of ChatGPT Plus subscribers who were active during this period had their payment information partially exposed, including names, email addresses, payment addresses, credit card types, and the last four digits of credit card numbers.
OpenAI's response was swift and appropriate. They shut down the service entirely, patched the vulnerability, notified affected users, and later launched a bug bounty program in partnership with Bugcrowd, offering rewards ranging from $200 to $20,000 for security researchers who identify vulnerabilities.
November 8-9, 2023: The DDoS Attack
In November 2023, ChatGPT experienced periodic outages caused by distributed denial-of-service (DDoS) attacks. The hacktivist group Anonymous Sudan claimed responsibility for the attack, citing political motivations related to the Israel-Palestine conflict and OpenAI's alleged bias.
The attack leveraged the SkyNet botnet to overwhelm OpenAI's servers with Layer 7 (application layer) DDoS attacks. OpenAI confirmed the attacks and worked to mitigate them, with service fully restored by November 9, 2023.
Interestingly, Anonymous Sudan was later revealed to potentially be a front for Russian-linked operations. In October 2024, a US federal grand jury indictment was unsealed, charging two Sudanese nationals with operating the group. The FBI seized their attack infrastructure in March 2024.
2024: Growing Pains
As ChatGPT's user base exploded and OpenAI rolled out more features in 2024, outage frequency increased slightly.
June 4, 2024: The Five-Hour Outage
One of the longest outages in ChatGPT's history occurred on June 4, 2024. The incident began around 2:30 AM ET when users started experiencing problems accessing ChatGPT via web, mobile apps, and desktop clients.
OpenAI acknowledged the issue on their status page, stating that they experienced a major outage impacting all users on all plans of ChatGPT. Importantly, this outage did not affect the API or platform.openai.com, which meant developers could still access the service programmatically even as the consumer-facing applications were down.
After more than five hours of downtime, OpenAI announced around 7:30 AM ET that a fix has been implemented. The exact cause was never publicly disclosed, though rumors of DDoS attacks circulated. OpenAI did not confirm any such attacks.
June 17, 2024: Another Major Disruption
Just two weeks later, another ChatGPT outage left users around the globe frustrated. This pattern of closely spaced outages highlighted the challenges OpenAI faced in maintaining stability during a period of rapid growth and feature deployment.
December 11, 2024: Configuration Error
A 4.5-hour outage on December 11, 2024, affected all OpenAI services including ChatGPT, the API, and the newly launched Sora video generation tool. The cause was identified as server configuration mistakes that rendered many servers unavailable.
This incident was notable because it demonstrated how a simple human error in configuration management could cascade into a service-wide outage. It also highlighted the interconnected nature of OpenAI's services, as all products were affected simultaneously.
December 26, 2024: Azure Infrastructure Failure
The day after Christmas brought one of the most significant outages in ChatGPT's history, lasting approximately 9 hours. This time, the cause was completely outside OpenAI's direct control: a power failure at Microsoft Azure's South Central US data center.
Starting at 10:40 AM on December 26th, multiple OpenAI products saw degraded availability. ChatGPT, Sora, and many APIs saw greater than 90% error rates during the incident. Only the text completions API was unaffected.
The root cause was a power failure in the cloud provider data center which impacted critical services such as databases in that region. OpenAI's databases are globally replicated, but region-wide failover required manual intervention from Azure. The scale of OpenAI's infrastructure elongated the mitigation time.
In response to this incident, OpenAI announced they would embark on a major infrastructure initiative to ensure their systems are resilient to an extended outage in any region of any of their cloud providers by adding a layer of indirection between their applications and cloud databases.
2025: The Year of Growing Challenges
By 2025, ChatGPT had become so deeply integrated into business workflows that outages began having measurable economic impact.
January 2025: Login Glitches
Early 2025 saw shorter incidents including login glitches that prevented users from accessing their accounts. While these were resolved relatively quickly, they foreshadowed more significant problems to come.
March 2025: Regional Outages and Rate Limits
March 2025 brought 3-hour regional outages that affected specific geographic areas. Around this same time, Sam Altman announced temporary rate limits due to overwhelming demand for ChatGPT's image generation features, posting on X that the company's GPUs are melting.
Free tier users were limited to 3 image generations per day while OpenAI worked to make the feature more efficient.
April 2025: Viral Trend Overload
A viral trend in April 2025 caused unexpected load on ChatGPT's servers, leading to service degradation. This demonstrated how unpredictable user behavior could strain even the most robust infrastructure.
May 2025: API Feature Breaks
System updates in May 2025 inadvertently broke certain API features, causing problems for developers who had built applications on top of ChatGPT's API. This highlighted the risks of depending on rapidly evolving AI services.
June 10, 2025: The Catastrophic 12+ Hour Outage
The worst ChatGPT outage in history occurred on June 10, 2025, affecting users globally for over 12 hours. This was not just an inconvenience; it was a wake-up call for the entire industry about AI infrastructure resilience.
The timing was particularly notable. Just one day earlier, Apple had announced a deep integration of ChatGPT into its devices at WWDC 2025. OpenAI had also announced reaching $10 billion in annualized recurring revenue and an 80% price cut for developers accessing the o3 reasoning models.
The outage began around 2-3 AM PT and persisted well into the afternoon. At 2:45 AM ET, users from North America, Europe, and Australia were unable to connect with ChatGPT and Sora. By 10 AM ET, OpenAI confirmed elevated error rates and latency and identified a solution in progress. Full recovery was not achieved until approximately 6:32 PM ET.
The technical cause was identified as routing layer nodes hitting memory limits and failing readiness checks. Eventually, a sufficient number of nodes became unavailable, leaving insufficient capacity to serve incoming traffic. The unprecedented volume of completions that morning was the tipping point.
November 2025: API and File Upload Issues
On November 8, 2025, between 5:42 AM and 7:16 AM PT, a large portion of requests to OpenAI failed with 502 or 503 error codes. All models and API endpoints saw significant failures.
A week later, on November 15, 2025, another outage affected ChatGPT APIs and file upload capabilities, impacting users' ability to process batch jobs and upload documents for at least 30 minutes.
December 2025: Continued Challenges
December 2025 saw another ChatGPT outage, bringing the total number of notable disruptions for the year to at least five. By this point, the pattern was clear: ChatGPT's infrastructure was struggling to keep pace with demand.
ChatGPT Uptime Statistics and SLA Information
Understanding the official uptime guarantees and actual performance helps set realistic expectations for ChatGPT reliability.
Consumer ChatGPT Uptime
OpenAI reports approximately 99.3% uptime for ChatGPT, which translates to roughly 0.7% downtime, or about 5 hours per month on average. This figure is an aggregate across all tiers, models, and error types. Individual customer availability may vary depending on subscription tier, specific model, and API features in use.
It is important to note that both free and paid ChatGPT Plus users experience identical disruptions during major outages. Plus subscribers get priority access during normal high-traffic periods, but when the entire service is impaired, everyone waits for engineers to restore service.
OpenAI's median time to recovery (MTTR) for 2025 incidents was approximately 2-3 hours, though this varied significantly based on the root cause.
Enterprise and Scale Tier SLA
For businesses requiring higher reliability, OpenAI offers Scale Tier, which provides a 99.9% uptime SLA along with prioritized compute resources. This translates to a maximum of approximately 8.77 hours of downtime per year.
Priority Processing is available for Enterprise customers, with latency calculated as p50 request latency on a per 5-minute basis. Service credits are offered if OpenAI fails to meet these SLAs.
However, it is worth noting that ChatGPT's 2025 outage pattern already exceeded typical enterprise SLA thresholds by mid-year, forcing corporate IT departments to reassess single-vendor AI strategies.
Azure OpenAI SLA
Microsoft provides a standard availability SLA for Azure OpenAI of typically 99.9% uptime. This means Azure OpenAI should be accessible for all except a few minutes each month. However, there is no explicit performance SLA guaranteeing that every response will be under a specific latency threshold, only the general uptime guarantee.
Technical Causes of ChatGPT Outages
Understanding why outages occur helps both users and developers prepare for and respond to them. The causes can be categorized into several main types.
Traffic Overload and Capacity Issues
The most common cause of ChatGPT outages is simply overwhelming demand. When massive numbers of users access the service simultaneously, especially during feature launches or viral trends, servers can become saturated.
The June 2025 outage is a perfect example: the routing layer nodes hit memory limits and failed readiness checks due to dramatically more completions than any prior day.
This type of outage is particularly challenging because it is often unpredictable. A viral meme, a major announcement, or simply organic growth can push demand beyond infrastructure capacity.
Software Updates and Deployment Issues
Deployment bugs and unexpected side effects from code changes are another major cause of outages. The December 2024 configuration error that took down all OpenAI services for 4.5 hours is a prime example.
AI systems are particularly vulnerable to deployment issues because they involve complex interdependencies between models, inference engines, caching layers, and application code. A change in one component can have cascading effects throughout the system.
Infrastructure and Cloud Provider Issues
OpenAI's heavy reliance on Microsoft Azure means that Azure outages directly impact ChatGPT. The December 26, 2024 outage was caused entirely by an Azure data center power failure, and there was nothing OpenAI could do but wait for Azure to resolve the issue.
This dependency creates a single point of failure that even OpenAI's engineers cannot directly address. It highlights the importance of multi-cloud strategies and redundancy, which OpenAI has committed to improving.
Security Incidents
Security vulnerabilities sometimes require emergency shutdowns to protect user data. The March 2023 incident, where a redis-py bug exposed user chat histories and payment information, required OpenAI to take ChatGPT completely offline while they patched the vulnerability.
Additionally, DDoS attacks like the November 2023 Anonymous Sudan attack can overwhelm services with malicious traffic, causing legitimate requests to fail.
Human Error
Configuration mistakes or mishandled deployments by human operators remain a persistent cause of outages across all technology services, and AI platforms are no exception.
How OpenAI's Infrastructure Works: A Technical Deep Dive
Understanding OpenAI's infrastructure helps explain both the challenges they face and why outages occur.
The Azure Partnership
OpenAI has a deep partnership with Microsoft Azure that goes far beyond a typical cloud customer relationship. As Greg Brockman stated, co-designing supercomputers with Azure has been crucial for scaling demanding AI training needs.
The wholesale bare metal experience that Azure provides OpenAI is very different from what typical cloud users get. When OpenAI rents entire data halls at a time, they have access to customized infrastructure specifically designed for their workloads.
GPU Clusters and Hardware
The latest generation of OpenAI's infrastructure uses NVIDIA GB300 NVL72 systems, the first supercomputing-scale production cluster of its kind. Microsoft Azure's NDv6 GB300 VM series features over 4,600 NVIDIA Blackwell Ultra GPUs connected via the NVIDIA Quantum-X800 InfiniBand networking platform.
Each rack integrates 72 NVIDIA Blackwell Ultra GPUs and 36 NVIDIA Grace CPUs into a single, cohesive unit. The system provides a staggering 37 terabytes of fast memory and 1.44 exaflops of FP4 Tensor Core performance per VM.
The previous generation used NVIDIA H100 Tensor Core GPUs, with each VM equipped with eight H100 GPUs and PCIe Gen5 providing 64GB/s bandwidth per GPU.
Networking Architecture
Connecting thousands of GPUs into a single supercomputer requires sophisticated networking. Microsoft Azure's cluster uses a two-tiered NVIDIA networking architecture designed for both scale-up performance within each rack and scale-out performance across the entire cluster.
Within each GB300 NVL72 rack, the fifth-generation NVIDIA NVLink Switch fabric provides 130 TB/s of direct, all-to-all bandwidth between the 72 Blackwell Ultra GPUs.
Cooling and Power
Delivering the world's first production NVIDIA GB300 NVL72 cluster at scale required reimagining every layer of Microsoft's data center infrastructure, from custom liquid cooling and power distribution to reengineered software stacks for orchestration and storage.
Azure's advanced cooling systems use standalone heat exchanger units and facility cooling to minimize water usage while maintaining thermal stability. They continue to develop new power distribution models capable of supporting high energy density and dynamic load balancing required by AI workloads.
