250ok vs Litmus: What are the differences?

Developers describe 250ok as "Verify, measure, and improve the performance of your email campaigns". 250ok is an email deliverability tools company that produces a Software‐as‐a‐Service (“SaaS”) platform to monitor and measure the deliverability of email networks. These networks consist of companies sending various forms of messages including marketing, transactional, share, and others from various platforms. On the other hand, Litmus is detailed as "*Email Testing and Email Marketing Analytics *". Litmus is a testing service for web and marketing professionals. It allows people to cross-browser test their websites, and test their email newsletters across a range of email clients and spam filters.

250ok belongs to "Email Deliverability" category of the tech stack, while Litmus can be primarily classified under "Email Testing".