Reliability
When OpenAI goes down,
your app stays up.
OpenAI has outages. Every major provider does. PromptUnit detects failures in real time and reroutes traffic automatically, before your users notice anything.
On April 20, 2025, OpenAI experienced a major outage that took down GPT-4o, the API, and ChatGPT for several hours. Teams whose AI features depended on a single provider either served errors to users or scrambled to manually reroute traffic. Teams running multi-provider infrastructure stayed up. The difference was not better engineering, it was having the failover layer already in place before the incident.
PromptUnit handles failover at the proxy layer. When a provider returns 5xx errors or connection timeouts, the proxy detects the failure within milliseconds and reroutes the request to the next available provider. Your application code never receives an error from a provider outage. The failover is transparent, users see a normal response, usually with a latency impact of under 200 milliseconds.
The failover target selection is not random. PromptUnit maintains a real-time availability and latency map across all connected providers. When a primary provider fails, the failover target is the fastest healthy provider that has a model capable of handling the same request type. A GPT-4o request failing over to Anthropic goes to Claude Sonnet rather than Claude Haiku if the complexity signals indicate the task requires it.
The SDK-level fallback adds a second layer of reliability. If PromptUnit itself is unreachable, a rare event, but possible, the SDK falls back directly to OpenAI. There is no single point of failure in the architecture. Your AI features degrade gracefully instead of going down completely.
Automatic failover
When a provider returns 5xx errors or times out, traffic is rerouted immediately. No alerts to set up, no runbooks to follow.
Zero downtime
Your application never receives an error from a provider outage. The failover is transparent, users see normal responses.
SDK-level fallback
If PromptUnit itself is unreachable, the SDK falls back directly to OpenAI. There is no single point of failure.
Cross-provider routing
Connect all your providers once. PromptUnit knows which models are equivalent and routes to the best available option.
Latency-aware selection
Failover targets are chosen based on both availability and latency. Traffic goes to the fastest healthy provider.
Incident visibility
Every rerouting event is logged with reason, provider, and latency impact. Full audit trail in your dashboard.
Supported providers
Connect API keys for each provider you want in your failover pool. PromptUnit handles dialect translation, your requests are always sent in the correct format for each provider, regardless of which SDK you use.
Who this is for
Multi-provider failover matters most for teams whose AI features are user-facing and where downtime has a direct business impact. If your product uses AI for core functionality, answering questions, generating content, processing requests, a single-provider dependency means that every OpenAI outage is your outage too.
Building failover in-house requires maintaining API clients for multiple providers, writing provider-selection logic, handling dialect differences between provider APIs, and keeping model equivalence mappings up to date as providers release new models. PromptUnit handles all of this through the same single integration point used for routing and cost optimization. Teams that already use PromptUnit for cost reduction get failover automatically when they connect their secondary provider API keys.
Add failover in 5 minutes
Connect your providers once. Failover works automatically from that point on.
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