We ranked 10 AI chat assistants by real-world reliability over the last 90 days, using 157 status page incidents and our own around-the-clock uptime checks. Many small businesses now draft emails, proposals, support replies and research in an AI chat assistant, so when the service goes down that work stalls or goes back to being done by hand. Outages in these services are frequent and often partial: one model, file uploads, voice mode or login can fail while the rest keeps working. Standard plans rarely come with an uptime commitment, so a vendor's incident history is the best guide to how often your team will be left waiting.
Most reliable AI chat assistant:Gemini (score 88.0/100). Highest uptime: DeepSeek Chat (100%). Fewest incidents: Gemini (1 in 90 days). Fastest to resolve: Grok (avg 1h 19m).
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Vendor
Score
Uptime (90d)
Incidents
Avg resolve
Transparency
Status now
1
GeminiGemini is Google's AI chat assistant, available on the web and mobile and included in Google Workspace business plans.Visit site ↗
88.0
99.94%
1
7h 22m
100/100
Operational
2
PerplexityPerplexity is an AI answer engine and chat assistant that cites web sources, with free, Pro and Enterprise plans.Visit site ↗
84.0
99.83%
8 (3 major)
1h 19m
100/100
Operational
3
GrokGrok is the AI chat assistant from xAI, available at grok.com, in mobile apps and inside X.Visit site ↗
83.4
99.78%
4 (4 major)
1h 19m
100/100
Operational
4
DeepSeek ChatDeepSeek Chat is the free web and mobile chat assistant from Chinese AI company DeepSeek.Visit site ↗
77.3
100%
20 (4 major)
—
100/100
Operational
5
PiPi is a conversational AI assistant from Inflection AI.Visit site ↗
57.0
99.01%
1 (1 major)
21h 11m
100/100
Operational
6
ClaudeClaude is Anthropic's AI chat assistant, available at claude.ai and in desktop and mobile apps with free and paid individual, team and enterprise plans.Visit site ↗
56.9
99.25%
39 (21 major)
1h 24m
100/100
Operational
7
ChatGPTChatGPT is OpenAI's AI chat assistant, available on the web, desktop and mobile apps with free and paid individual, team and enterprise plans.Visit site ↗
32.2
96.85%
84 (9 major)
6h 19m
100/100
Operational
AI Chat Assistants reliability at a glance
Across the 7 ranked AI chat assistants, average 90-day uptime is 99.24%. Reliability scores range from 88.0 (Gemini) to 32.2 (ChatGPT).
Together they published 157 incidents in the last 90 days, 42 of them partial or major outages.
The typical vendor takes 3h 52m to resolve an incident. Grok is fastest, at 1h 19m on average.
ChatGPT reported the most incidents (84 in 90 days).
What to check before you choose a AI chat assistant
Look at which parts of the assistant fail most often. Login and conversation errors stop all work; a problem with one model, voice mode or image generation can usually be worked around.
Keep a second assistant set up and signed in. Switching tools is the only failover most chat assistants offer, and it's easier if your prompts and files live outside the chat.
Check how long incidents last, not just how many there are. Short error spikes are routine for AI services; multi-hour outages during your working day are what cost you time.
If your team relies on it every day, ask whether a business plan includes an uptime commitment or priority access at busy times, and subscribe to the status page.
90-day uptime history
Each bar is one day. Hover a bar for that day's uptime and incidents.
These vendors join the ranking once we have enough evidence: at least 14 days of data, and for vendors with a quiet status page (silent for a year, or for 90 days while their competitors report several incidents), 30 days of our own independent monitoring.
Based on the last 90 days of data, Gemini is the most reliable AI chat assistant we track, with a reliability score of 88.0/100 and 99.94% uptime.
How do you measure AI chat assistant reliability?
We poll each vendor's public status page every few minutes, record every incident, and run our own uptime checks against each vendor's login and customer-facing pages. Uptime (40%), incident frequency (20%), average time to resolve (20%) and transparency (20%) combine into one score out of 100.
How often are these rankings updated?
Continuously. Status pages and uptime checks run every five minutes and scores are recalculated several times an hour.
Can vendors pay to rank higher?
No. Sponsored placements are clearly labelled, shown separately from the rankings and never change a vendor's score.