CostcoUK

Complete guide on our Costco UK module

Use the CostcoUK module for Costco’s UK website. Checkout requires a Costco UK account. Normal tasks log in, add the product to your basket and attempt checkout; Monitor tasks watch for stock and notify checkout tasks.

Quick Start (Recommended Setup)

1. Prepare your Costco UK account with a valid membership, default UK delivery address and saved payment details. Make your Stellar profile’s email, address and payment details match the account.
2. Save the account in Stellar’s Accounts tab under Costco. Adding it saves the credentials; the Normal task logs in when it starts.
3. Create a CostcoUK task group. For random restocks, start with one Monitor task per product and one Normal checkout task per account, with Watch Task enabled on the checkout task.
4. Enter the complete product SKU, including any letter at the end. Clear your Costco basket before starting.
5. Start with a 3000 ms Normal delay. The monitoring starting point in this guide is 5000 ms, with a 5000 ms Reset Delay. Adjust for proxy performance and release guidance.
6. Choose your OTP Input method and prepare it before starting. For timed or queue releases, follow the release instructions and leave Watch Task off when running checkout independently.

Preliminary Checklist

• Account and membership: confirm you can sign in to Costco UK in a browser and that the account is ready to buy.
• Profile: use accurate contact, delivery and payment information that matches the account. Costco UK takes the delivery address from the account; changing only the profile does not replace that address.
• Proxies: prepare UK proxies. You can try UK ISP/datacenter and residential providers; performance varies, so avoid relying on only one provider. Stella Proxies remains one option from the existing setup guidance.
• Product: get the exact SKU and quantity limit from the product page or your UK cook group. A cook group is optional but useful for release details and stock alerts.
• OTP access: keep access to the account’s email inbox. OTP means the one-time verification code used during login.
• Preparation: check the setup before a major release. A running Normal task can place a real order, so only test with an item you intend to purchase.

Accounts & Sessions

1. Open Accounts, expand Costco and choose an account group, or create one with New Group.
2. Click Add Account. Enter an optional Account Name, the Costco UK Account Email and Account Password, then Save.
3. Create a profile with the same email and matching address/payment information. In your Normal task, explicitly select the saved account in Account.
4. When the Normal task starts, it uses the saved credentials to log in. Complete any requested email verification using your selected OTP Input method.

Use one checkout task per account as the starting rule. Multiple checkout tasks on the same account can compete over its basket and login session. Clear the basket manually before a release. Stellar can add a payment card if it is missing, but prepare and verify the account’s saved details in advance rather than relying on a last-minute correction.

Supported Modes

• normal — logs in to the account and attempts to add the product to the basket and check out.
• monitor — checks for stock and signals checkout tasks that have Watch Task enabled. It does not purchase the item.

Normal Mode — Checkout

In your CostcoUK group, click Create Task and select normal. The screenshot shows Endless Mode enabled only to reveal Endless Limit; beginners can leave it off.

• Name: choose a label that helps you identify the product and account.
• Mode: select normal.
• Profile: select the matching checkout profile.
• Checkout Proxy: select your UK checkout proxy group.
• Product SKU: enter the complete Costco UK item code, not the full product URL. See the SKU example below.
• Delay: the form defaults to 3000 ms (3 seconds). This controls the task’s request interval. Adjust if your proxies are being blocked; a lower delay is not automatically better.
• Qty: the quantity of this product to buy. Start with 1 unless the release allows more; Stellar does not automatically correct a quantity that exceeds Costco’s limit.
• Account: select the saved Costco UK account. Checkout is account-based even though the selector is not marked with an asterisk.
• OTP Input: select IMAP, Manual or AYCD. IMAP retrieves the email code from a configured inbox; Manual requires you to enter the code; AYCD uses your configured AYCD setup. Select a method you have already prepared.
• Start Time / End Time: optional scheduling. Leave blank when you plan to control the task yourself.
• Endless Mode: repeats checkout attempts after a successful checkout until the configured Endless Limit is reached. Leave it off for a single checkout. It does not bypass Costco’s purchase limits.
• Endless Limit: appears when Endless Mode is enabled. Set the intended limit before using that option.
• Watch Task?: enable for a checkout task that should wait for a Monitor task to find stock. Leave it off for independent checkout, including the queue setup described in this guide.
• Stop Task After Carting?: stops after adding the product to the basket so you can attempt checkout manually. Carting is not a completed order or a stock guarantee.
• Add or Renew Membership?: allows the task to add or renew a membership if needed. Enable only if you intend to purchase or renew that membership; leave it off when your account is already ready.
• Bottom Qty: how many tasks to create. This is separate from the product Qty. Keep it at 1 for your first task, then click Create.

Monitor Mode — Watch for Stock

Create another task in the CostcoUK group and select monitor. Start with one Monitor task per SKU.

• Name: use a recognizable monitoring label.
• Mode: select monitor.
• Profile: an optional profile selector is available in the current form. This mode does not check out.
• Monitor Proxy: select the proxy group used for stock checks.
• Product SKU: enter the same complete SKU used by the checkout task.
• Monitor Delay: the current form defaults to 3000 ms. The existing Costco UK starting recommendation is about 5000 ms (5 seconds); adjust to proxy quality and release instructions.
• Reset Delay: about 5000 ms is the existing starting recommendation. Use it with the monitoring setup and adjust according to release guidance.
• Start Time / End Time: optional scheduling.
• Bottom Qty: number of Monitor tasks to create. Usually 1 per SKU is enough. Click Create, then start the Monitor and the Normal checkout task with Watch Task enabled.

For example, to watch SKU 1930406A for a random restock, use that SKU in one Monitor task and in one Normal task for your account. Enable Watch Task on Normal. “Waiting For Monitor” means it is waiting for the stock signal; it is not a login error.

Finding the Correct Product SKU

Open the product on Costco UK and look at the end of its URL. For example, www.costco.co.uk/Toys-Baby-Child/Toys-Games/Collectables/Pokemon-TCG-Mega-Charizard-X-ex-Ultra-Premium-Collection-6-Years/p/1930406 uses SKU 1930406.

Some products have variants. Select the variant on the product page and check the updated URL: if it ends in 1930406A, enter 1930406A, including the A. Developers have confirmed that omitting the variant letter can cause “handling cart 400 / INVALID PRODUCT CODE.” Your cook group may also provide the exact SKU.

Frequently Asked Questions

How many tasks should I run?

Start with one Monitor task per SKU and one checkout task per Costco account. Extra monitors are usually unnecessary. Avoid simultaneous checkout tasks sharing an account because they can interfere with its basket and session.

Should I use residential proxies or ISPs?

Try UK-based providers and keep a small, tested mix if needed. Proxy quality and Costco’s blocking can change. Use a reasonable delay instead of assuming more tasks or faster requests will help.

What should I do during a queue release?

Follow the current release announcement. Leave Watch Task off when running the checkout task through the queue independently, and allow it to wait for the queue to pass. Restarting is not a reliable queue bypass and may interrupt progress.

Can I complete checkout manually?

Yes. Stop Task After Carting is available for that setup. If an item is in your basket, sign in to the correct Costco UK account and review it before paying. First check order history and confirmation emails so you do not place a duplicate order.

Common Errors & Fixes

Waiting For Monitor

This is a normal waiting status when Watch Task is enabled. Make sure a Monitor task for the same full SKU is running. For a timed release or independent checkout setup, use the recommended release settings rather than leaving the task waiting for a monitor you have not created.

Handling cart 400 / INVALID PRODUCT CODE

Check the complete SKU. Choose the product variant on the website and include any letter suffix, such as 1930406A. Do not use the parent item code when a variant is required.

Invalid credentials or repeated login failures

Verify the email/password and try signing in to Costco UK manually. Developers have noted that Costco website/account login problems can also cause this message. Confirm your OTP method can access the correct inbox. Update Stellar and seek support if manual login works but the task still fails.

Akamai Ban or Kasada Ban

These can involve proxy blocking or an account/site restriction. Try another suitable UK proxy and allow a blocked account time to recover. If manual login also fails, resolve that on Costco first. Reset the password only if Costco’s account recovery or support guidance calls for it; it is not a guaranteed fix for a proxy block.

Initiating checkout errors / HTTP2 or mobile-services errors

Check whether the account and Costco website work manually, then compare another proxy. These messages alone do not prove the account is blocked. If the item was carted, you can review the basket for manual checkout after checking that no order was already placed.

Error submitting order / server error

Check the profile against the account’s saved address and payment details, confirm the card is supported, and install available Stellar updates. Costco traffic or website errors may also be involved. If it continues, send the task error and logs to support with private payment information hidden.

Out of stock

Confirm the exact variant is available and that your account has not reached a product purchase limit. Website availability can change before checkout; increasing task quantity does not bypass limits.

Payment declined

Check Costco order history and confirmation emails first. Developers have reported cases where an order completed despite a decline message. If no order exists, review the saved payment details, profile and basket before trying manual checkout. Do not assume an Added to Cart status means the purchase succeeded.

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