What does CPU time mean?
Active CPU time is the time spent executing work: routing a request, running application logic, processing a query result or serializing JSON. Wall-clock request duration also includes time waiting for other systems to respond.
Isoplane’s hosting model bills for active CPU time, measured to the millisecond. Idle time between requests and time waiting for I/O during a request are free. Network egress is free too.
A 200ms response can use 5ms of CPU
This illustrative request shows how execution and waiting contribute to response time and CPU billing.
| Stage | Time | Isoplane CPU billing |
|---|---|---|
| Prepare the database query | 2ms | 2ms |
| Wait for the database | 195ms | Free |
| Process the result and respond | 3ms | 3ms |
The client receives its response after 200ms, while the bill accounts for 5ms of active CPU. Your database provider’s charges remain separate.
Does every await stop CPU billing?
CPU billing follows the work your app executes. Awaiting an I/O operation can let the app stop executing until a response arrives. Work that runs before or after that wait still consumes CPU. An asynchronous method that performs computation still does billable work.
Which .NET APIs benefit?
Database-backed APIs, webhooks and APIs that call other services are useful examples to examine. Measure how much CPU each request actually uses and how much time it spends waiting. A CPU-heavy workload, such as processing a large document, has less waiting time to exclude from the bill.
Scaling to zero between requests and excluding I/O wait within a request answer different questions. Isoplane’s model makes both periods free.
Compare the complete hosting bill
“Pay for use” can refer to different units. Check active CPU, provisioned memory, request counts, minimum subscriptions, network transfer and any separate storage or database services.
- Cloudflare Workers uses active CPU billing alongside request charges and a subscription on its paid plan.
- Vercel Fluid compute bills active CPU separately from provisioned memory and invocations. Memory billing continues while requests wait for I/O.
- With Isoplane, you pay for CPU time, with free idle time, I/O wait and egress.
We’ll release our full pricing details when we enter public preview. If you’d like to make a true dollar-for-dollar comparison today, please request to join our private preview and we’d be happy to discuss pricing with you.
What can I try today?
Request private preview access and tell us about your app’s traffic, database and external calls. We’re starting with async .NET APIs, and we’d love to hear what you want to build.