Introduction

SpacePost is an email API for developers, built on Amazon SES. It speaks the Resend API: the same paths, the same JSON request and response shapes, the same error format and the same webhook signing scheme. If your code works with Resend, it works with SpacePost after changing a base URL.

You get the deliverability and price of SES, with the developer experience of a modern email API: a clean REST API, SDKs, a CLI, an MCP server, an SMTP relay for tools that cannot call an API, signed webhooks, scheduling, batch sending, audiences and broadcasts.

What you can do

• Send transactional email with one POST /emails call: HTML, text, attachments, inline images, tags, custom headers, scheduling, idempotency keys.
• Send up to 100 emails per request with the batch endpoint.
• Receive events (email.delivered, email.bounced, email.opened…) on signed webhooks.
• Send newsletters to audiences with personalization and one-click unsubscribe.
• Relay SMTP from Supabase Auth, WordPress, Laravel, Django, Rails or any app that speaks SMTP.
• Protect your reputation with an automatic suppression list and automatic pausing when bounce or complaint rates get dangerous.

How it works

your app ──HTTPS──▶ api.spacepost.dev ──▶ queue ──▶ Amazon SES ──▶ recipient
   ▲                                                 │
   └──── signed webhooks ◀── events (SNS/SQS) ◀──────┘

1. Your request is validated and counted against your quota, then stored and queued. The API answers with an id immediately.
2. A worker builds the MIME message, drops suppressed recipients and hands it to SES with your domain’s DKIM identity.
3. SES reports delivered, bounced, complained, opened and clicked. SpacePost records them on the email, updates last_event, adds hard bounces and complaints to your suppression list and calls your webhooks.

How it compares

	SpacePost	Resend	SendGrid	Raw AWS SES
API shape	Resend-compatible	Resend	Its own	AWS SDK / SMTP
Free tier	3,000 / month	3,000 / month, 100 / day	100 / day	Sandbox
Entry paid plan	€9 for 50,000	USD 20 for 50,000	Varies	USD 0.10 per 1,000
Overage per 1,000	€0.25	USD 0.90	Varies	USD 0.10
Dashboard, logs, webhooks	Yes	Yes	Yes	Build it yourself
Suppression list	Automatic	Automatic	Automatic	Build it yourself
SMTP relay	Yes	Yes	Yes	Yes
Audiences and broadcasts	Yes	Yes	Yes	No
Official Resend SDKs work	Yes (set the base URL)	Yes	No	No

SpacePost prices are in EUR and exclude VAT. Resend’s and AWS’s prices are their published USD prices (Resend’s as of 23 October 2026), shown as published and not converted.

Plans in one line

Free: 3,000 emails per month, 3 domains. Pro: €9, 50,000 emails, 10 domains. Scale: €35, 200,000 emails, 1,000 domains. Prices per month, excluding VAT. See Plans and quotas.

Concepts

Teams

Everything belongs to a team: domains, API keys, emails, webhooks, audiences. Quotas and reputation are tracked per team.

Domains

You send from addresses on a verified domain, such as hi@acme.com. Verification takes three DKIM CNAMEs.

API keys

Keys start with sp_live_. full_access keys use every endpoint, sending_access keys can only send, optionally from one domain.

Emails and events

Each email has a UUIDv7 id and a last_event such as delivered. The full timeline is in the dashboard and on webhooks.

Next steps

QuickstartSend your first email in five minutes.

Migrating from ResendSwitch an existing integration.