Outage during a demand peak
Launch, campaign, drop or market event takes the product down.
Severity: outage. Attached to 9 of 46 published product types, backed by 12 evidence records.
Product types that carry it
| Product type | Grade | Note for this type | Evidence |
|---|---|---|---|
| crypto exchange | practitioner single incident, no second source | A price spike drives a traffic surge, and traders cannot place or cancel orders while the market moves. | |
| stock trading app | primary | On a market-wide sell-off morning, login and order entry go down at the open, and customers cannot close positions while prices move. | |
| telemedicine app | practitioner single incident, no second source | A release before morning clinic leaves too few servers, and patients booked for the first slots cannot check in to the virtual waiting room. | |
| event ticketing platform | practitioner single incident, no second source | A stadium tour presale opens to fans and bots at the same minute, and the queue and seat map fail for part of the buyers. | |
| ride-hailing app | secondary | New Year's Eve and Halloween ride requests peak at once across every city, and matching, pricing and billing must all hold at that volume. | |
| LLM-based assistant | primary | One account scripts long prompts in a loop and uses up the shared token budget and rate limit, so other users' chats stop answering. | |
| messaging app | primary | After a holiday every client reconnects at once with a cold cache and downloads channel history, and the reconnect storm takes the service down. | |
| mobile game | primary | Launch-day or live-event player traffic far above forecast overloads the game backend, and players cannot log in or play. | |
| government services portal | secondary | When an enrolment or benefits window opens, every applicant arrives at once and the portal fails, as GAO found for a federal site launched without performance verification. |
Tests that address it
- release smoke tests: mandatory for this risk on 3 product types.
- performance and load testing: mandatory for this risk on 9 product types.
- resilience and failure testing: mandatory for this risk on 6 product types.
Evidence
ev-0027regulatorprimary
PS21/3: Building operational resilience, Financial Conduct Authority
The FCA requires UK firms to identify important business services, set impact tolerances and test that they can stay within them during severe but plausible disruption.
published undated · verified 2026-10-07
ev-0066post-mortemprimary
Incident Post Mortem: June 1, 2020, Coinbase
Supports outage-under-load for crypto exchanges.
published undated · verified 2026-10-07
ev-0161practitionersecondary
Reliability at Scale: Engineering an Uneventful New Year's Eve, Uber Engineering
With users worldwide relying on Uber for safe and reliable transportation to and from their celebrations, New Year's Eve often marks our highest traffic event of the year, with Halloween as a close second.
Engineering blog write-up describing holiday demand peaks and event drills that load-test every service from ride request to billing. Supports outage-under-load for ride-hailing apps.
published 2017-11-30 · verified 2026-10-07
ev-0173post-mortemprimary
Doxy.me site not loading, Doxy.me Inc.
During the incident, users were unable to access doxy.me for telehealth sessions, leading to delayed or missed appointments and interruptions in patient care.
Official post-mortem from a telehealth video platform: a release lowered the number of active servers, morning traffic overwhelmed the rest, and patients could not check in to their visits. Supports outage-under-load for telemedicine apps, where demand is concentrated at scheduled appointment times.
published 2025-04-29 · verified 2026-10-07
ev-0177post-mortemprimary
Taylor Swift | The Eras Tour Onsale Explained, Ticketmaster
The ticket seller's own account of a presale where bot traffic and fans without presale codes drove record system load and disrupted part of the queue. Supports outage-under-load and fraud-abuse for an event ticketing platform.
published 2022-11-19 · verified 2026-10-07
ev-0181court-or-fineprimary
Robinhood Financial LLC Letter of Acceptance, Waiver and Consent, FINRA
During the March outage, all of Robinhood's customers were unable to trade.
Supports outage-under-load, wrong-decisions and regulatory-penalty for a stock trading app: the regulator found a retail brokerage app went down during the March 2020 market volatility, showed customers inflated negative cash balances and approved options accounts through automated approval bots with limited oversight.
published 2021-06-30 · verified 2026-10-07
ev-0242regulatorsecondary
Healthcare.gov: Ineffective Planning and Oversight Practices Underscore the Need for Improved Contract Management (GAO-14-694), U.S. Government Accountability Office
Supports outage-under-load for a government services portal: GAO found the federal enrolment site launched without verification that it met performance requirements and many users could not access or use it.
published 2014-07-30 · verified 2026-10-07
ev-0276standardprimary
LLM10:2025 Unbounded Consumption, OWASP Gen AI Security Project
The OWASP entry describes high-volume and oversized requests that degrade service availability and run up per-token cost (denial of wallet) for the operator of an LLM application.
published undated · verified 2026-10-07
ev-0286post-mortemprimary
Slack's Outage on January 4th 2021, Slack Engineering
On January 4th, one of our Transit Gateways became overloaded. The TGWs are managed by AWS and are intended to scale transparently to us.
Supports outage-under-load and dependency-failure for a messaging app: clients returning after the holidays reconnected with cold caches, and a cloud-managed network gateway did not scale with the surge.
published 2021-02-01 · verified 2026-10-07
ev-0287post-mortemprimary
Slack's Incident on 2-22-22, Slack Engineering
When the whole system is in overload, retries increase load and make recovery less likely, so clients should ideally avoid sending requests until the system has recovered.
Supports outage-under-load for a messaging app: a cache tier emptied by restarts met peak traffic, and users whose chat client was not already connected could not connect.
published 2022-04-26 · verified 2026-10-07
ev-0291post-mortemsecondary
Bringing Pokémon GO to life on Google Cloud, Google Cloud
Within minutes of launching in Australia and New Zealand, player traffic surged well past Niantic's expectations.
Supports outage-under-load for a mobile game: the cloud provider's engineering write-up describes launch traffic for a location-based mobile game far above the publisher's forecast and the scaling work that followed.
published 2016-09-30 · verified 2026-10-07
ev-0292post-mortemprimary
Roblox Return to Service, Roblox
Enabling a relatively new streaming feature on Consul under unusually high read and write load led to excessive contention and poor performance.
Supports outage-under-load for a mobile game: the company's post-mortem shows a game platform used on phones taken down when its service-discovery cluster failed under high load.
published 2022-01-20 · verified 2026-10-07