What are some alternatives?
When comparing LetsNews.app and MailChimp, you can also consider the following products
Mailtrain - Self-hosted open-source Mailchimp clone
SendInBlue - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.
Listmonk - Send e-mail campaigns from a powerful dashboard. High performance and features packed into one app.
GetResponse - Email marketing from GetResponse. Send email newsletters, campaigns, online surveys and follow-up autoresponders. Simple, easy interface. FREE sign up.
IMAP API - Self hosted and lightweight daemon application
Campaign Monitor - Email marketing software built for designers and their clients to run successful email campaigns.