How can I integrate free AI tools like text-to-image or chatbots into my website using public APIs?

I am currently running a project at AIToolClouds.com, where I showcase and review various AI Tools (like text-to-image, chatbots generators, background removers etc.)
I want to take it a step further by integrating some of these tools directly into my site using open-source APIs or free-tier services. My goal is to allow users to try out tools like:

  1. AI Image generation (eg using Stable Diffusion or DALL.E)
  2. Simple chatbot interfaces using OpenAI or other models.
  3. Background remover or text-to-speech tools.

My Questions

  1. Are there any public APIs or open source libraries that I can use to embed these tools (preferably with free tiers)?

  2. What is the best way to manage rate limiting and performance when using these APIs on a live website?

  3. Any suggestions for frameworks or platforms ideal for integrating such AI features( I m using wordpress+ a custom HTML/JS Section)?

Any help or code snippets would be appreciated! Also happy to share how I am testing these tools at AIToolClouds.com