Grok API is prepaid and billed by usage. When an account has no available balance, requests fail immediately. The symptom may be insufficient quota, or it may be a permission error that is hard to interpret. For teams in mainland China, the real obstacle is often not model capability but payment: which currency, how the exchange rate is calculated, how long crediting takes, whether an invoice is available, and whether unused balance can be refunded.

This article separates the official and gateway paths and gives checkpoints for before payment, after crediting, and during reconciliation. Specific unit prices, exchange rates, and promotions are subject to model pricing and the top-up page on this site. No figures are hard-coded here.

Note: xAI and Grok are trademarks of their respective owners. This article is for technical reference only. Payment methods, prices, and invoice policies may change; refer to xAI's official pages and model pricing on this site.

1. Distinguish the two top-up paths

Path A: an official xAI account

Complete billing setup in the xAI console, attach a payment method that xAI supports, and purchase credit as needed. The advantage is a clear billing entity and immediate access to models once they launch. The trade-off is that you need a usable overseas payment method, stable access to the console, and you must handle exchange rates, tax, and internal reimbursement yourself.

This path suits teams with an overseas entity or payment channel that mainly use Grok.

Path B: a domestic AI gateway

Register at the ZSQH AI Gateway, top up the account balance in RMB, and call Grok with an API key from the same account. A gateway usually provides an OpenAI-compatible endpoint, so an existing OpenAI SDK only needs a new base URL and key.

This path suits teams that pay domestically, need RMB invoices, connect several model providers, and want to see all usage in one backend. The two paths do not replace each other; they differ in billing entity and operational boundaries.

Comparison Official xAI Domestic AI gateway
Settlement currency Per the official bill RMB
Payment method Methods supported by xAI Common domestic payment methods
Crediting speed Depends on the payment channel Online payment is usually fast; bank transfers may need manual confirmation
Invoices Per official policy Requested under the gateway's policy
Model scope xAI's own models Multiple enabled models
Operational scope You handle network and payment The platform handles the endpoint and billing integration

2. Official xAI top-up process

  1. Sign in to the xAI console and confirm the account entity, billing address, and terms of use.
  2. Open the billing or credit page and review the current balance, billing method, and available payment methods.
  3. Attach a payment method and confirm the charge currency, whether cross-border fees apply, and where the transaction details appear.
  4. Purchase a small amount first and make one successful call. Confirm that credit arrives and billing works before adding more according to usage.
  5. If the console offers auto-recharge, set a reasonable trigger threshold and per-charge amount so a usage spike does not interrupt service.
  6. Save the order number, payment receipt, and a screenshot of the billing page for your finance team.

Console labels and payment options can vary by region and version; follow the actual page. Before paying, confirm three things: the charge currency, how the conversion is calculated, and the amount of credit you will receive. If the page says only "payment successful" without explaining the conversion, ask the provider before making a large payment.

3. Gateway top-up process

  1. Open the ZSQH AI Gateway, register, and sign in.
  2. Go to the top-up page, choose an amount, and confirm the payment method, credited amount, and any promotion terms.
  3. Complete payment and keep the order number and payment receipt.
  4. Return to the console and check that the "balance" and "transactions" pages agree.
  5. Create or select an API key and set a per-project spending limit.
  6. Verify that the key, balance, and model all work with one minimal request.
  7. Once confirmed, add balance according to business volume.

The key to a gateway top-up is not that the money goes in, but that the books reconcile. For company accounts, keep top-up, invoicing, usage, and reconciliation in one process. Do not wait until month-end to discover that order numbers and invoice amounts do not match.

4. Exchange rates, fees, and credited balance

A gateway settles in RMB, but behind the scenes it must convert RMB to pay the upstream provider. Cost usually has three layers: the settlement exchange rate, the payment channel fee, and the platform service fee. You can check them with the following formula:

Credited balance = RMB paid ÷ settlement rate − channel fee − service fee

You do not need to memorize any specific number. You only need to confirm three things on the top-up page:

  1. Which line shows the exchange rate, and whether it is a live rate, an end-of-day rate, or a fixed rate.
  2. Whether fees are listed separately, whether they are embedded in the exchange rate, or whether they are charged on top.
  3. Whether the credited balance follows the formula above, and whether you can work backward from the order amount.

Also distinguish "cash balance" from "bonus balance." Bonus credit often cannot be refunded or invoiced, may expire, and may be consumed after cash balance. For corporate budgeting, account for the two separately; otherwise a discrepancy appears at month-end.

5. Post-payment checklist

After topping up, check the following in order. This prevents most "payment succeeded but the balance did not arrive" problems:

  1. Save the order number, payment time, and amount paid, with a screenshot.
  2. Compare the balance page with the transactions page and confirm that the credited amount matches the order.
  3. Check whether the key has its own spending limit; a sufficient balance can still be blocked by a key-level cap.
  4. Confirm that the requested model is enabled for the current account or group.
  5. If payment succeeded but the balance did not change, contact support with the order number. Do not pay twice.
  6. Before a large top-up, verify the path with a small amount: payment, crediting, and calling should all work.

Crediting time depends on the payment channel. Online payment is usually fast; bank transfers may require manual confirmation, and cross-bank or non-business-day transfers can be slower. Build this delay into procurement schedules. Do not wait until the day a service goes live to top up.

6. Invoices and reconciliation

Item What to confirm
Invoice type Standard VAT invoice or special VAT invoice
Invoice entity Company name, tax ID, address and phone, bank and account number
Invoice amount Based on the amount paid or the credited balance
Invoice timing How long after payment, and whether retroactive issuance is supported
Supporting documents Order number, contract, and payment receipt
Correction rules How wrong, reissued, or reversed invoices are handled

For corporate procurement, put invoice requirements in the purchase order rather than asking after payment. For individual testing, top up a small amount first, confirm that the model and call path work, and then add more, so balance does not sit unused. Keep top-up records, order numbers, and invoice files for at least one financial cycle; they are needed during reconciliation.

7. First call after topping up

Once the balance arrives, confirm the full path with one minimal request:

export GROK_API_KEY="sk-your-key"

curl "https://ai.zhongshangqihang.com/v1/chat/completions" \
  -H "Authorization: Bearer $GROK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "grok-4",
    "messages": [{"role": "user", "content": "Reply with OK only"}],
    "max_tokens": 16
  }'

A 200 response containing a choices field means the key, balance, and model all work. If you receive a quota-related error, check in this order:

  1. Whether the balance has arrived and appears in the transactions page.
  2. Whether this key has a spending limit.
  3. Whether the requested model is enabled for the current account.
  4. Whether you are hitting a rate or concurrency limit rather than a balance problem.
  5. Whether the base URL matches the key's source.

FAQ

Is a top-up the same as a subscription?

No. A subscription is for using a product as an individual, while an API top-up is for programmatic calls. Their quotas are usually separate and cannot offset each other. When purchasing, be clear about which one you are buying.

After paying in RMB, is the bill in USD or RMB?

It depends on the provider. A gateway usually issues RMB orders and RMB invoices, while the usage page may also show USD consumption for comparison with the upstream provider. Follow the actual billing page.

How long does crediting take?

Online payment is usually fast. Bank transfers may require manual confirmation, depending on the payment channel and platform notices. For large top-ups, allow at least one business day of buffer.

Can unused balance be refunded?

It depends on the platform terms. Unused cash balance, bonus balance, and consumed amounts follow different rules. Confirm this when topping up, not after you stop using the service.

Why do two identical requests cost different amounts?

Input length, output length, cache hits, model tier, and tool calls all affect the charge. Match the request ID against the usage log to locate the difference.

Next steps

If you need RMB top-ups, consolidated billing, and RMB invoices while calling Grok and other models, sign up for the ZSQH AI Gateway, top up a small amount, and verify one request before splitting keys by project. Specific prices, exchange rates, and invoice rules are subject to model pricing.

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