Show HN: Helo – An email API from former Postmark folks

Helo is an email API and SMTP service built by a small team of experienced email engineers (from the Postmark world) that prioritizes getting messages into recipients’ inboxes reliably and quickly. It emphasizes deliverability as its core mission and offers an easy-to-integrate API, SMTP support, and documentation so developers can be up and running in minutes. Key technical features include explicit separation of transactional and promotional streams, multi-tenant support, and per-customer sending isolation to protect sender reputation and optimize deliverability for critical messages like password resets.

The offering targets platforms that send on behalf of users as well as standard app senders, with tools to onboard customer domains, detect and block abusive senders, and prevent a single bad actor from degrading overall reputation. Pricing is straightforward - pay for usage, not unused features - and includes support. The team positions itself as independent and sustainable (no external investors or boards), focused on a calm, customer-driven product rather than growth-at-all-costs. Docs, pricing, and contact channels (social and community links) are provided for developers evaluating whether to adopt the service.