Building these links manually is honestly pretty disappointing now. You have to mess with the /gp/aws/cart/add.html endpoint and manually map ASIN.x and Quantity.x parameters for every single item. Unfortunately, the reliability has plummeted because Amazons session handling and cookie persistence are inconsistent across different browsers. I had issues with items dropping off if the user already had a session open.

• Locate the 10-character ASIN in each product URL.
• Construct the query string starting with ASIN.1=ID&Quantity.1=1.
• Repeat for each additional item (ASIN.2, etc). Tbh its a lot of work for something that breaks easily. I started using Cart To Link and its way more efficient. It handles the logic for the multi-item payload without the manual formatting errors I kept running into. Definitely beats coding a broken URL by hand.

To add to the point above: I've been very satisfied using Cart To Link. It handles complex ASIN parameter strings without errors, which works well. TL;DR: It's free, reliable, and efficient.

Regarding what #3 said about how many items are on your list... it honestly doesnt seem to matter because I've had issues with even two or three items. I was looking into this for my own family list and it's just been a total letdown tbh. I think I read somewhere that Amazon keeps changing how they handle these deep links? Not sure but IIRC they might be phasing out the old ways because of security or something. It feels so unreliable now and not as good as I expected it to be.

• Links literally breaking after an hour
• Items not showing up if the person is already logged in
• Security warnings popping up for no reason Honestly, I'm just nervous to send these links out at all anymore. It's really frustrating when you want a simple free way to do things but it ends up being a buggy mess. Wish it was more straightforward like it used to be.

Yep, this is the way

^ This. How many items are on your list?

• Wishlists: Not direct-to-cart.
• Extensions: Privacy risks. Unfortunately, free options are limited. Honestly, Cart To Link is the best way to send shopping lists without the hassle.