idle cost
rented vm / container
A rented container or VM bills 24/7 even when the agent serves zero requests.
a2a cloud
Scale-to-zero Knative service holds no agent replica when idle.
pay when it runs
Scale-to-zero AI agent hosting.
An AI agent is idle most of the day, but a rented box bills every hour — and that hosting cost stacks on top of per-token model spend. On a2a cloud, on-demand agents run as Knative container services that scale to zero when idle and start again for new traffic. You pay for invocations, not uptime.
idle = free · pay per invocation · free tier
0$
idle cost
0
free invocations/mo
free agent
the problem
You're paying for an agent that mostly waits.
Most agents spend the overwhelming majority of their life idle — waiting for the next request. Host one on a container or VM and you pay for every one of those idle hours anyway, at capacity sized for a peak you rarely hit. Layer per-token model spend on top and idle becomes the most expensive part of running an agent: you're billed to keep a box warm so it can do nothing.
A rented container or VM bills 24/7 regardless of how many requests it serves.
Capacity is provisioned for peak traffic, so you overpay during the long quiet stretches.
Hosting cost stacks on top of per-token model spend — idle is billed twice over.
Real isolation usually means a dedicated VM you keep warm and pay for continuously.
the a2a way
Right-size the agent to the traffic it actually gets.
a2a runs on-demand agent services on Knative and scales their replicas with traffic. Explicit ctx.sandbox code execution uses a separate microsandbox microVM; it is not the hosted serving lifecycle.
Scale to zero when idlePay per invocationFree tier to startServerless cold startsSeparate code-execution sandboxThe whole app scales with it
Scale to zero when idle
Each on-demand agent runs as a Knative container service that scales to zero when there is no traffic and wakes on the next request.
Pay per invocation
Billing follows requests, not wall-clock. You pay for the runs your agent actually serves instead of renting a box by the hour whether it works or sleeps.
Free tier to start
The free tier covers one hosted agent and 10,000 invocations a month. Ship a real agent, put it in front of users, and pay nothing until you outgrow it.
Serverless cold starts
Knative starts a container revision when traffic arrives, then scales it back down after the idle window. Warm lifecycle settings are available when latency matters more than zero idle compute.
Separate code-execution sandbox
Hosted skills run in the agent container. Code explicitly sent through ctx.sandbox executes in a separate microsandbox microVM without turning every request into a VM lifecycle.
The whole app scales with it
The managed Postgres, MCP server, gateway, and frontend that ship with the agent ride the same model — so the whole agent app is right-sized to actual traffic, not provisioned for peak.
side-by-side
Always-on box vs. scale-to-zero.
billing model
rented vm / container
You pay by the hour for provisioned capacity, sized for peak you rarely hit.
a2a cloud
You pay per invocation — cost tracks the runs your agent actually serves.
on top of tokens
rented vm / container
Hosting bills stack on top of per-token model spend, doubling the cost of idle.
a2a cloud
Idle hosting is free, so per-token spend is the only cost while the agent waits.
isolation
rented vm / container
Real isolation usually means a dedicated VM you keep warm and pay for continuously.
a2a cloud
Explicit code execution uses a separate microsandbox; hosted serving still scales to zero.
getting started
rented vm / container
Even a demo agent needs a paid instance running before anyone can try it.
a2a cloud
Free tier: one agent and 10,000 invocations a month, deployed at no cost.
dimension
rented vm / container
a2a cloud
idle cost
A rented container or VM bills 24/7 even when the agent serves zero requests.
Scale-to-zero Knative service holds no agent replica when idle.
billing model
You pay by the hour for provisioned capacity, sized for peak you rarely hit.
You pay per invocation — cost tracks the runs your agent actually serves.
on top of tokens
Hosting bills stack on top of per-token model spend, doubling the cost of idle.
Idle hosting is free, so per-token spend is the only cost while the agent waits.
isolation
Real isolation usually means a dedicated VM you keep warm and pay for continuously.
Explicit code execution uses a separate microsandbox; hosted serving still scales to zero.
getting started
Even a demo agent needs a paid instance running before anyone can try it.
Free tier: one agent and 10,000 invocations a month, deployed at no cost.
questions
Frequently asked.
What is scale-to-zero agent hosting?
Scale-to-zero means an on-demand agent's Knative container service can have zero replicas when idle and start a revision for new traffic. You pay for invocations rather than keeping an agent container warm around the clock.
How does pay-per-invocation lower agent hosting costs?
Agents are idle most of the time, but a rented container or VM bills around the clock — on top of per-token model spend. Pay-per-invocation ties cost to the runs you actually serve, so idle time is free and hosting no longer doubles the cost of an agent that mostly waits.
Doesn't scale-to-zero mean slow cold starts?
A request can trigger a Knative cold start when the service has zero replicas. Actual latency depends on image size and startup work; a warm lifecycle can keep a replica ready when that tradeoff is worthwhile.
Is there a free tier for hosting an AI agent?
Yes. The free tier includes one hosted agent and 10,000 invocations per month, so you can deploy a real agent — with its database, MCP server, gateway, and frontend — and put it in front of users before paying anything.
Do I still get isolation with scale-to-zero?
Hosted agent processes run in Knative or Kubernetes containers. When the agent explicitly sends code through ctx.sandbox, that command runs behind a separate microsandbox virtualization boundary.
keep reading
Related guides.
All guides live in the guides index.
idle costs nothing
Pay only when your agent runs.
a2a cloud deploys any agent as a scale-to-zero Knative service with managed Postgres, MCP, an API gateway, and a hosted frontend. Agent API, public /invoke, and standard MCP tools/call executions receive signed receipts.