Building blocks

Pricing & billing

Billed-on-success, the prepaid wallet, hold-then-capture, and how to read usage.

ARCNM bills only on success — failed runs, 4xx/5xx responses, and idempotent replays cost €0 — and holds billable work against a prepaid wallet, capturing it when the run succeeds. The rules:

Billed on success. Failed runs, 4xx/5xx responses, and idempotent replays cost €0.
Prepaid wallet. You top up a balance; billable work is held against it and captured on success.
You stay in control. The wallet is prepaid — we never auto-charge a saved card without an explicit auto-refill rule you set.

For current rates, see arcnm.io/pricing.

New accounts start free. Every new organisation is granted a one-time welcome credit worth its first 5 successful runs — no card required. It's an ordinary wallet credit, so it follows the same rules below: a failed run never burns one, and once it's used up a run returns 402 insufficient_funds until you top up.

Hold, then capture

When you run a calculation (/run — also reached via /quote and /upload-and-quote), ARCNM pre-authorises a wallet hold for the cost of the run before any work starts:

If the wallet can't cover it, the run returns 402 insufficient_funds synchronously — no work is performed.
If the run succeeds, the hold is captured.
If the run fails, the hold is released — you aren't charged.

This is why a leaked parts:read key can never spend money: only parts:write can place a hold.

Outcome	Billed?
Calculation succeeds	Yes
Calculation fails / cancelled / timed out	No (hold released)
`4xx` / `5xx` before work	No
Idempotent replay	No

Pay-as-you-go vs subscriptions

Model	Bills	Best for
PAYG (wallet)	Top up a balance, captured per successful run	Spiky workloads, prototyping, agencies
Subscription	Monthly committed spend; overage auto-PAYG against the same wallet	Steady workloads, line-itemed invoices
Enterprise	Annual committed spend with custom SLA	Production, regulated workloads

Switch any time from the dashboard.

Wallet top-ups

Top up from the dashboard (Settings → Billing) or the Customer Portal. The wallet is prepaid; set an "auto-refill at €X" rule if you want hands-off topping up.

Reading your balance and usage

Read your wallet balance and period usage with a key carrying the wallet:read scope via the billing/wallet API. Detailed transaction and hold history are available on the same surface, and the dashboard (Settings → Billing) renders all of it alongside invoices and receipts.

Invoices, receipts, tax

Subscriptions, invoices, and the Customer Portal are handled through our billing provider. The org owner sees invoices and receipts in the dashboard (Settings → Billing). VAT is collected per the customer's billing country where applicable.