Why am I receiving a 400 error when updating rich text content through the API?

If you are seeing an error when submitting HTML content through the API to a rich text field, it is likely that you have included invalid characters that need to be escaped. 

 JSON uses quotes "" to identify different values in the list, so if your content included a URL like this: <a href="https://....">  it will read it as if the "h" is the start of a new item.

In order for it to read the information correctly, you need to escape any quotes that don't need to be read as an actual quote by placing a \ in front of it. For example, instead of <a href="https://...."> you need to have <a href=\"https://...\"> .