SendLayer

SendLayer is a transactional sender focused on API and SMTP relay, domain authentication, logs, suppression management, bounce handling, blocklist monitoring, event webhooks, and analytics. Plans are simple but billed annually, and the entry plan is small at 1,000 emails per month.

An agent stack treats email as a two-way primitive. Inbound has to arrive as structured JSON a tool call can consume, sends have to be safe to retry when a model loop repeats itself, and every action needs an audit trail. A provider without inbound parsing only solves half the problem.

Against inbound parsing into tool calls and model-generated sends that must not duplicate, SendLayer covers webhook coverage, event stream, and batch sending, and does not cover inbound parsing, idempotency keys, SDK breadth, and multi-tenant support. Whether that gap matters depends on how central those are to the build.

• Inbound parsing: No
• Idempotency keys: No
• Webhooks: Yes
• Operating since: Not published
• Event stream: Yes
• Best published rate per 1,000: Tiers not published in comparable form
• Batch sending: Yes
• SDKs: None
• Multi-tenant: No

Transactional sender with authentication, active anti-spam, bounce handling, blocklist monitoring, and event-based webhooks. Public independent deliverability history is thinner than Postmark or SMTP2GO.

Small WordPress, app, or SaaS projects that need simple transactional delivery at low volume.

Teams that want monthly billing or large free-tier volume.