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.

^ 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.