# Payment, Limits, and Top-Ups

Three controls on **Settings → Billing** belong to you: the payment method on file, a monthly
spending limit, and automatic top-up. Everything else about the account — the billing model,
the debt limit, and suspension — is set by Fours under an approval trail.

---

## Add a payment method

You do **not** need one to use Insulin. The $100 monthly free credit is spendable without a
card, and most accounts never add one. Add one when you want automatic top-up, or when you
are moving to monthly billing.

1. Open **Settings → Billing**.
2. Under **Payment method**, select **Add payment method** (or **Add another** if one is
   already saved).
3. You are taken to **Stripe's hosted checkout page** to enter the details, then returned to
   the same billing page.

Cards and US bank accounts are both accepted. Saved methods are listed by brand and last four
digits — *Visa ending 4242*, *Bank account ending 6789*.

:::info
**No card details are entered in the Fours console.** The form is Stripe's, on Stripe's page.
Fours stores a reference to the method, never the number.
:::

If the payment provider is briefly unavailable the panel says so and states plainly that your
credit balance and AI usage are unaffected — it is a problem on Fours' side, not something to
fix in your own settings.

## Set a monthly spending limit

A ceiling on what the organization may spend in a calendar month, whichever billing model it
is on.

1. Under **Monthly spending limit**, enter an amount in US dollars.
2. Select **Save limit**.

To remove it, select **Remove**, or clear the field and save. An empty field means *no limit*.

| Rule | Detail |
|---|---|
| Range | 0 to $100,000 per month |
| When it applies | Compared against the month's spend so far, on both billing models |
| What it does | Pauses AI requests for the rest of the month |
| What it also does | **Stops automatic top-up** — you asked not to spend more |
| Resets | At the start of the next month |

**Reaching your limit is not the same as running out of credit,** and the fix is different:
your balance is untouched, so adding credit will not resume service. Raise or remove the limit
instead. See [When AI pauses](/insulin/billing/when-ai-pauses/).

A limit set below what you have already spent this month applies straight away, though it can
take up to a minute for in-flight requests to start being refused.

## Turn on automatic top-up

Automatic top-up charges your saved payment method once the balance is at or below a trigger
you choose, so a long-running job is not interrupted by a balance nobody was watching.

1. Save a payment method first — the switch is disabled without one, because there would be
   nothing to charge.
2. Turn on **Automatic top-up**.
3. Set **When the balance is below** (the trigger) and **Top up by** (the amount).
4. Select **Save top-up settings**.

| Rule | Detail |
|---|---|
| Requires | A saved payment method |
| Trigger range | 0 to $100,000 |
| Top-up range | Greater than 0, up to $100,000 |
| Hard rule | **The top-up must be larger than the trigger** |
| Checked | Every five minutes |
| Overridden by | Your monthly spending limit |

**Why the top-up must exceed the trigger.** A top-up that lands back on its own trigger fires
again immediately, and again after that. It is the only setting on this page that can charge
real money repeatedly rather than once, so the console refuses to save it.

Credit added this way is **Purchased credit** and stays valid for three years — it is not
lost at the end of the month.

:::warning
**A payment method removed later silently disarms automatic top-up.** If the setting is on but
no method is saved, the panel says so and nothing will be charged. Add a method to restore it.
:::

### How the limit and the top-up interact

Your monthly spending limit wins. Once the month's spend reaches it, no top-up is charged for
the rest of the month, whatever the balance does — charging you for credit you asked not to
spend would defeat the point of setting a limit. The panel states this above the Save button
whenever a limit is set.

This is the order the two controls are evaluated in, and it answers the two questions people
arrive with: *why didn't my top-up fire?* and *why didn't adding credit bring the service
back?*

```d2
direction: down
classes: {
  q: { shape: diamond; width: 260 }
  stop: { width: 250; style.border-radius: 8 }
  ok: { width: 250; style.border-radius: 8 }
}

trigger: "Balance falls to\nyour top-up trigger" { style.border-radius: 8 }
limit: "Month's spend already\nat your monthly limit?" { class: q }
method: "Payment method\nsaved?" { class: q }

blocked: "No top-up is charged\nfor the rest of the month.\nRaise the limit to resume." { class: stop }
disarmed: "Top-up is disarmed.\nAdd a payment method." { class: stop }
charged: "Top-up is charged\nand the balance rises" { class: ok }

trigger -> limit
limit -> blocked: yes
limit -> method: no
method -> disarmed: no
method -> charged: yes

blocked -> note: "" { style.opacity: 0 }
note: |md
  Adding credit does **not** clear the
  monthly limit — the limit is a cap on
  spend, not on balance.
| { style.border-radius: 8; width: 300 }
```

So a paused service resumes only once the blocking condition itself is cleared: raise or remove
the **monthly spending limit** if that is what stopped it, and add **credit** if the balance is
what stopped it. Adding credit while the limit is reached changes nothing until the next month
or until you raise the limit. [When AI pauses](/insulin/billing/when-ai-pauses/) walks the full
set of pause conditions.

## What you cannot change here

| Setting | Who sets it |
|---|---|
| Billing model (pay as you go / monthly) | Fours, effective the following month |
| Debt limit — how far below zero the account may go | Fours |
| Suspension | Fours |
| The monthly free credit amount | Fours |
| The spend point at which Fours-hosted models step down a tier | Fours |

These sit behind an approval trail on Fours' side, recorded with who changed them, when, and
why. Contact [support@suger.io](mailto:support@suger.io) to request a change.

### The Fours-hosted tier step-down

The last row is worth stating plainly, because nothing on screen announces it.

The Fours-hosted model pool has two tiers: a **Tier 1** quality model and several lighter
**Tier 2** models. Once your organization's spend **on Fours' own key** passes about **$300**
in a billing period, Tier 1 stops being offered for the rest of that period and the pool
serves Tier 2.

| | Detail |
|---|---|
| What is counted | Only spend on Fours' key — your own [BYOK](/insulin/billing/metering/#using-your-own-provider-keys-byok) usage is not counted toward it |
| Over what window | Your billing period, not a calendar month |
| What changes | Tier 1 is withheld; Tier 2 stays available |
| What does not change | Nothing is paused, refused, or refunded |
| Resets | At the start of the next period |

**It is not one of the [reasons AI pauses](/insulin/billing/when-ai-pauses/).** Those are
refusals, and each raises a banner telling you which one applied. This is not a refusal: no
banner appears, no request fails, and no conversation stops — the pool simply has fewer
models in it, and answers may read as less capable.

**Your own models are unaffected.** A connected provider's models are always preferred over
the hosted pool, so an organization running on its own keys never meets this at all. If you
want Tier 1 quality past that point, connect your own provider — see
[how a turn resolves to a model](/insulin/agents/#how-a-turn-resolves-to-a-model).

## If a payment fails

Stripe retries a failed payment on its own schedule, up to four attempts, before the cycle is
treated as exhausted. Nothing happens to your account during the retries — the most common
cause is a temporary hold or a card that gets replaced within a few days.

Once the retries are exhausted:

| Billing model | What happens |
|---|---|
| Pay as you go | The organization is suspended and notified. Update the payment method, then contact Fours to lift the suspension — it is not cleared automatically when a payment succeeds. |
| Monthly billing | Nobody is cut off automatically. You are notified, and Fours' team follows up about the outstanding balance. |

Stored files and running sandboxes are unaffected either way.