Now, I've used tray.io, Zapier, and Automate.io for different reasons.

Tray.io is great if you have some complex, custom integrations needed, such as automated lead generation fueled by web scraping with APIFY, although I would urge you to try PhantomBuster first as it is cheaper... OR wire them up together if you want to save some time and create some sick multi-step processes involving conditionals, loops, and transformed data.

Zapier is a little limited in scope sometimes, and you might need to get hacky to get things to work just as you want them to, but that inevitable becomes a house of cards.. Plus, Zaps are expensive.

SO if you need to build something of high complexity where you expect a lot of throughput, I recommend Tray.io because you simply pay one monthly fee for as many requests as you would like.

You are instead limited by the number of "Workflows" you can make, which is their "Zap" equivalent.

It's pretty low, but if you practice with their Sales team and develop them well before signing a contract, you'll be in good shape to generate your ROI.