Introduction

Start with the Quickstart to submit a test email before DNS verification. Test emails are accepted but never delivered. Live sending requires a verified domain and a live key, and remains limited during the public preview. API acceptance does not guarantee delivery.

The API reference is generated from the OpenAPI spec and documents every request and response. Its samples use plain HTTP. SDKs for Node.js, Go and PHP are not published yet, and there is no Python SDK.

Use llms.txt to find Markdown copies of the guides and API reference, or download the public OpenAPI document for API tooling.

• Authentication and test mode
• Domains and DNS
• Sending, scheduling, idempotency and email list paging
• Webhooks, signature verification, deliveries and resend
• Errors, rate limits, suppressions and data retention
• Usage for the current plan caps, and readiness beside liveness

Production runs in AWS eu-central-1 (Frankfurt) and sends through Amazon SES. SMTP relay and dedicated IPs are not supported, and there is no open or click tracking: SES adds no tracking pixel and does not rewrite links. Live event streams stay in the dashboard and are not a public API. Platform system mail, such as sign-in and welcome messages, is not a customer endpoint.

Generated API reference samples use the placeholder https://api.sendtier.example. Replace it with https://api.sendtier.com before running them. API paths have no /v1 prefix.

Sources: OpenAPI (openapi/openapi.yaml), public Quickstart (site/src/components/quickstart.tsx), ADR-0008 (docs/adr/0008-sdk-generator.md), SES configuration (internal/ses/sesv2.go, internal/config/config.go, infra/terraform/variables.tf), SES event types (infra/terraform/main.tf), Node SDK (sdk/typescript/README.md), Go SDK (sdk/go/README.md), PHP SDK (sdk/php/README.md).