useSend

useSend is an API-first email delivery platform built for transactional and marketing email workflows. It adopts an architectural model comparable to Resend while remaining fully open source and self-hostable. This combination enables teams to standardise email delivery without surrendering control over infrastructure, deployment topology, or data locality.

The platform exposes a REST-based interface for email delivery and supports provider-native capabilities such as templates, dynamic variables, and scheduled sends. By abstracting the underlying delivery infrastructure, useSend simplifies application integration while allowing organisations to retain operational and regulatory control.

Operation

useSend functions as a dedicated email delivery layer rather than a low-level SMTP utility. Applications interact with the platform exclusively over HTTP, delegating authentication, delivery orchestration, and provider integration to useSend.

This separation reduces application-level coupling to SMTP configuration and provider-specific behaviour. As a result, email delivery remains consistent across environments and is well suited to serverless architectures and short-lived runtime contexts where traditional SMTP configuration is impractical.

Platform

Within the platform, useSend centralises delivery logic, credential management, and provider abstraction. Applications issue standardised API requests, while useSend handles message preparation, scheduling, and dispatch through the configured provider.

This model streamlines maintenance and reduces operational risk by isolating email delivery concerns from core application logic.

Deployment

useSend supports managed cloud and self-hosted deployment models, each exposing an identical API surface. The managed cloud option provides a hosted endpoint with minimal operational overhead, enabling rapid adoption and simplified scaling.

Self-hosted deployments allow teams to operate useSend within their own infrastructure. This option is particularly relevant for organisations with regulatory, privacy, or data residency obligations, as it enables full control over data flow and storage.

Adapter

PayloadCMS useSend Email Adapter (@rubixstudios/payload-usesend) integrates PayloadCMS with useSend by replacing Payload’s native email transport layer. The adapter connects to Payload v3 through the standard email configuration interface, ensuring compatibility with existing projects.

Once configured, calls to payload.sendEmail() continue to function without modification. The adapter translates Payload’s email payloads into useSend’s REST API format, including support for template identifiers, template variables, and scheduled delivery parameters.

Scope

PayloadCMS useSend Email Adapter is intended for projects that require REST-based email delivery, template-centric workflows, and flexibility between managed and self-hosted infrastructure models. It is specifically designed to operate reliably in serverless and short-lived runtime environments.

The adapter replaces only the delivery mechanism. Payload’s email API, abstractions, and calling patterns remain unchanged, ensuring minimal integration effort and low migration risk.