[antolepore]

I need to send simple text messages via email to many recipients.

Hi everyone, I'm looking for a reliable free service for sending text
messages via email to many recipients without being blocked by various
anti-spam filters.

I don't have to spam but I have to warn as many people as possible
with alerts every now and then.

I don't have to make a mailing list because the email addresses
always change depending on the case.

What can I use?

[Disease]

I need to send simple text messages via email to many recipients.

Hi everyone, I'm looking for a reliable free service for sending text
messages via email to many recipients without being blocked by various
anti-spam filters.

I don't have to spam but I have to warn as many people as possible
with alerts every now and then.

I don't have to make a mailing list because the email addresses
always change depending on the case.

What can I use?

How many alerts are you sending at once? Or daily?

Either way, you need an SMTP relay. Whether you stand one up yourself, or use a service like SendGrid. The advantage to using a reputable service is you're less likely to end up in spam folders. This is because those those services will have appropriate DKIM/DMARC DNS records setup, as well as be recognized as reputable. The downside is they usually cost money. SendGrid is free for up to 100 emails/day, but beyond that, it requires payment. You'll also be under guidelines for what you're sending out- won't really get away with malicious emails, for example.