So what is session infrastructure?
Every AI app runs the same loop.
Receive input. Call a model. Maybe run a tool. Store what happened. Repeat.
The loop is the part you write.
Everything around it — the transcript, the sandbox, the keys, the retries, the cost meter, the place to look up what your agent did yesterday — that's session infrastructure.
It's not glamorous. But every AI app needs it.
Calling the model is the easy part.
That run cost us about a hundredth of a cent. The hard work is everything around the call: keeping the conversation, retrying when the model fails, running code in a safe place, holding your API keys without leaking them.
You could build this yourself.
None of it is hard.
A table for the conversation. A sandbox for tool calls. A vault for the keys. A retry layer. Some glue.
You could ship a working version by Friday. You probably will.
The trouble starts on Monday.
Each one breaks on its own schedule.
Anthropic is rate-limited at 2pm and your agents stall. OpenAI moves a feature behind a flag overnight. A sandbox provider raises prices. A key needs to be rotated. You usually find out from a customer. With us, you swap to a different model mid-run — same session, no transcript loss, your users keep going.
Soon you fix bugs more than you ship features.
Each fix is fast on its own. Add them up over six months and your team has spent half its time on plumbing instead of on the product you set out to build.
And the bill will surprise you.
A prompt loops at 3am and costs $40 by morning. One customer doubles their usage and eats your monthly budget. You'll build cost caps, per-tenant meters, and a "why did we spend $1,200 last week" dashboard. Cerver shows every session's cost the moment it ends — and lets you route through your existing Claude Pro / ChatGPT subscription before paying per token, so the cheap path is the default, not the bolt-on.
And we read between the lines.
Every session is a transcript. Every transcript is a tiny customer interview.
A thousand of them in, and you've got a research panel — except the answers are real.
We run an agent across yours on a schedule. It reports what your users keep asking, where they get stuck, what feature they're begging you to ship next.
The infra you came for. The product insight you didn't know you needed.
You don't build Stripe. Don't build this either.
Stripe handles your payments.
Twilio handles your SMS.
Vercel handles your hosting.
Cerver handles the part between your code and an LLM. The whole part. Sessions, sandboxes, secrets, retries — full-time.
Use ours for the same reason you use theirs.
It's not your product.
Free until it's worth paying for.
You bring the keys. We bring the rest.
Your LLM keys. Your vault. Your compute provider, if you have one. The model calls go on your bill, not ours.
We sit between, doing the parts that broke last Tuesday.
Use cerver free until you're running enough sessions to feel the value.
Then we charge. By then, you'll be glad.