What credits are

Running a build costs money, because it calls a large language model and models are billed by the token. Bookbag gives you two ways to cover that:

1. Credits. Bookbag uses its own AI provider key and charges your balance for the tokens your build used. You hold no key and configure nothing.
2. Your own provider key. Your builds run on your key, the provider bills you directly, and no credits are spent at all. See Your own AI key.

Credits exist for people who would rather not hold a key. They are not the only way in.

What a credit is

A credit is a unit of build cost, worked out from the tokens your build actually used, at a rate set per model. There is no fixed price per build and no per-message charge — a one-line change costs a fraction of what a large first build costs.

The details are in How a build spends credits.

Credits belong to you, not to an organization

Your balance is personal. It follows you into every organization you belong to. Building in a colleague's organization spends your credits, not theirs, and there is no shared organization pot.

The same is true of your monthly allowance and of your own provider key, if you add one.

The monthly allowance

Your balance tops up to your allowance once a month. The default allowance is 500 credits, and an administrator can change that default, or set a different one for you personally.

Three things about the top-up that are easy to get wrong:

It is a top-up to the allowance, not an addition of it. If your allowance is 500 and you have 120 left, you are topped up to 500 — you receive 380, not 500. If you have 620 (because an administrator granted you extra), you receive nothing.

Unused credits do not roll over. They are not lost either — they are simply already counted in the balance the top-up levels you to.

It happens once per calendar month, and only once. If you burn your balance to zero on the 3rd, you are not topped up again until the 1st of the next month. There is no second top-up mid-month.

The check runs every few minutes, so the top-up arrives shortly after the month turns, and also the moment you next try to build if your balance is at zero.

Where your first credits come from

From the monthly allowance. The first time Bookbag has a reason to look at your balance — your first visit to the account page, or your first build — a credit account is created for you, and the allowance sweep tops it up shortly afterwards.

Bookbag has a signup grant setting, visible to administrators on the admin credits page and defaulting to 300. In the current build no code path awards it, so it is a stored setting with no effect. New accounts get their first credits from the monthly allowance instead.

Running out

Your balance is checked in two places.

Before a run starts. If it is at or below zero, Bookbag first tries the monthly top-up. If that does not help, the run refuses before spending a single token:

You are out of credits. Your balance tops up monthly, or you can add your own AI key under Account → AI and build without credits.

The run is recorded as failed and nothing is charged.

Between steps during a run. If your balance reaches zero partway through, the run stops at the next step boundary:

The run stopped because your credits ran out. What was built so far is saved.

That run ends as done, not failed, and everything already written to your app stays written.

What still works at zero

Almost everything. A zero balance blocks metered build runs and nothing else. You can still:

• open, read and download every project,
• browse the source and the version history,
• restore a version,
• run the security check,
• publish, republish and take a site offline,
• add your own AI key and start building again immediately at no credit cost.

On /account a warning appears:

You are out of credits, so builds are paused. Your balance refills at the start of next month — or contact an administrator.

A balance can go negative

The check before a run only asks whether your balance is above zero, not whether it is enough for the run you are starting. The charge is settled after the run, from the tokens it actually used. A large run started with three credits left can therefore finish with a negative balance.

That is intentional — the provider charged for those tokens, so the ledger records them honestly rather than pretending the run was free. The next monthly top-up brings you back up to your allowance, so a negative balance corrects itself.

Where to see your balance

• The sidebar, next to Account & credits.
• The project page's top bar, as a small pill. It refreshes when a run completes.
• /account, as a large number with your full ledger beneath it.

Next

• How a build spends credits.
• The credit ledger.
• Your own AI key — how to spend none at all.