Hello Radu,
Hope you are doing absolutely great.
Instead of writing Proposal I would like to approach you directly for this job, as we have been working on the AWS for last 3 years. Let's take this forward as it looks like you need of an AWS expert and slack app developer to build a simple slack app.
We have a working experience in node.js, MongoDB, Express JS, NoSQL Couch & Mongo, PostgreSQL, webRTC, MySQL, PHP, System Admin, frontend and backend development, load balancing, Video Broadcasting, Video Services, Amazon Web Services, Cloud Computing, Linux, Network Administration, System Admin, Database Management.
So, here I’m confident that we will able to work on your project. Looking for to connect with you in chat.
Best Regards,
Akash!