opensend Ruby SDK

Minimal first-party Ruby SDK for OpenSend transactional email sends with a Resend-shaped API surface.

Use your OpenSend API key (os_...) with the Resend-compatible API surface.

Installation

This package is staged for future RubyGems publishing. From this repository today:

bash

cd packages/ruby-sdk
gem build opensend.gemspec
gem install ./opensend-0.1.0.gem

After publication, the intended package install is:

bash

gem install opensend

Setup

Use an environment variable instead of hardcoding API keys:

bash

export OPENSEND_API_KEY="os_your_api_key"

For self-hosted OpenSend, point the SDK at your deployment origin. The default hosted origin is https://api.opensend.com.

bash

export OPENSEND_BASE_URL="http://localhost:3015"

Send an email

The module-level surface mirrors Resend's Ruby ergonomics:

ruby

require "opensend"

OpenSend.api_key ENV.fetch("OPENSEND_API_KEY")
OpenSend.base_url ENV.fetch("OPENSEND_BASE_URL", OpenSend::DEFAULT_BASE_URL)

email = OpenSend::Emails.send(
  from: "hello@yourdomain.com",
  to: "recipient@example.com",
  subject: "Hello from OpenSend",
  html: "# It works!"
)

puts email.fetch("id")

Resend is also exported as an alias constant for migration-oriented code:

ruby

require "opensend"

Resend.api_key ENV.fetch("OPENSEND_API_KEY")
email = Resend::Emails.send(
  from: "hello@yourdomain.com",
  to: ["recipient@example.com"],
  subject: "Hello from OpenSend",
  text: "It works!"
)

Instance client

ruby

client = OpenSend::Client.new(
  api_key: ENV.fetch("OPENSEND_API_KEY"),
  base_url: ENV.fetch("OPENSEND_BASE_URL", OpenSend::DEFAULT_BASE_URL)
)

email = client.emails.send(
  from: "hello@yourdomain.com",
  to: "recipient@example.com",
  subject: "Hello from OpenSend",
  html: "# It works!"
)

Errors

Non-2xx API responses raise OpenSend::Error (also exported as OpenSend::APIError). The exception keeps OpenSend's public error envelope fields when present.

ruby

begin
  OpenSend::Emails.send(params)
rescue OpenSend::Error => error
  warn [error.status_code, error.code, error.message, error.details].inspect
end

Supported first slice

OpenSend::Emails.send(params) → POST /emails
OpenSend::Client#emails.send(params) → POST /emails
Bearer API key auth
Configurable base URL
Structured API error envelope parsing
Resend alias constant for migration-oriented send code

This first package intentionally does not implement batch sends, async jobs, attachments helpers, or the full Resend resource surface yet.

Tests

bash

ruby -I packages/ruby-sdk/lib packages/ruby-sdk/test/opensend_test.rb