UniOne Ruby on Rails 1.1.3

Web API 1.90

Quickstart guide: Send emails with Ruby · Docs for LLMs: llms.txt · API reference

Ruby on Rails integration of the UniOne Ruby SDK (unione): the API client in the application config (config.unione), a webhook endpoint with signature check, a Action Mailer transport that sends through email/send.

bundle add unione-rails

Requirements: Ruby 2.7+, Rails 6.1+.

1. Sign up at cp.unione.io.
2. Copy your API key from Settings → Security → API.
3. Put it in an environment variable:

export UNIONE_API_KEY="your-api-key"

The package reads it from UNIONE_API_KEY (see the configuration below).

Server-side only. Use this package in backend code: API routes, server functions, workers. Never ship the API key to a browser or a mobile app, and never commit it.

Settings are read from the environment by default:

# .env / environment: UNIONE_API_KEY=YOUR_API_KEY
# or config/application.rb:
config.unione.api_key = ENV.fetch('UNIONE_API_KEY')
config.unione.host = 'us1.unione.io'
config.action_mailer.delivery_method = :unione

The API key can also be stored in the credentials (unione: { api_key: ... }). The webhook route unione_webhook is a Rack endpoint (no CSRF, no session); config.unione.webhook_enabled = false turns it off.

Every account can send test email right away from a sandbox domain: pre-verified, DKIM and SPF already set. It delivers only to addresses you confirm.

The examples use the API client of the package (see the configuration above).

1. Get your sandbox domain (domain/get-sandbox-domain). The call creates the domain on first use and returns the same one afterwards.

response = UniOne::Wrapper.client.domain.get_sandbox_domain
puts response.domain

2. Confirm your inbox (confirmed-email/create). UniOne sends a confirmation email; click the link in it within 48 hours.

ConfirmedEmail = UniOne::Api::ConfirmedEmail::Model

response = UniOne::Wrapper.client.confirmed_email.create(ConfirmedEmail::ConfirmedEmailRequest.new(
  email: 'you@example.com'
))
puts response.status

Check the status with confirmed-email/list — your address should show "status": "confirmed".

3. Send the email (email/send) from any address on the sandbox domain to the confirmed address.

Common = UniOne::Common::Model
Email = UniOne::Api::Email::Model

response = UniOne::Wrapper.client.email.send_email(Email::EmailSendRequest.new(
  message: Email::MessageObject.new(
    recipients: [
      Email::MessageObjectRecipientsItem.new(
        email: 'you@example.com'
      )
    ],
    body: Common::BodyObject.new(
      html: '<p>It works!</p>'
    ),
    subject: 'Hello from UniOne',
    from_email: 'noreply@<sandbox-domain>'
  )
))
puts response.job_id

{
  "status": "success",
  "job_id": "1ZymBc-00041N-9X",
  "emails": [
    "you@example.com"
  ]
}

On error the API returns status: "error", a message and a numeric code:

{
  "status": "error",
  "code": 102,
  "message": "Error ID:83274F98-C7D5-11F1-B221-6214FF8707B1. Can not decode key wrongkey"
}

BASE=https://api.unione.io/en/transactional/api/v1

curl -s -X POST $BASE/domain/get-sandbox-domain.json \
  -H "Content-Type: application/json" -H "X-API-KEY: $UNIONE_API_KEY" -d '{}'

curl -s -X POST $BASE/confirmed-email/create.json \
  -H "Content-Type: application/json" -H "X-API-KEY: $UNIONE_API_KEY" \
  -d '{"email": "you@example.com"}'

curl -s -X POST $BASE/email/send.json \
  -H "Content-Type: application/json" -H "X-API-KEY: $UNIONE_API_KEY" \
  -d '{
        "message": {
          "recipients": [
            {
              "email": "you@example.com"
            }
          ],
          "from_email": "noreply@<sandbox-domain>",
          "subject": "Hello from UniOne",
          "body": {
            "html": "<p>It works!</p>"
          }
        }
      }'

Messages of the Action Mailer go through email/send: from, to/cc/bcc, reply-to, subject, HTML and text parts, attachments, inline images and X-* headers.

class OrderMailer < ApplicationMailer
  def shipped(order)
    headers['X-Order-Id'] = order.id.to_s
    attachments['invoice.pdf'] = order.invoice_pdf
    mail(to: order.email, cc: order.manager_email, subject: 'Order shipped')
  end
end

message = OrderMailer.shipped(order).deliver_now
message.delivery_method.response['job_id']

The endpoint answers GET with 200 OK (the URL check of webhook/set) and accepts the POST notifications: it checks the auth field (MD5 of the request body in which the auth value is replaced by the API key), answers 401 to a wrong signature, and passes the notification and each of its events to the application.

# config/initializers/unione.rb
ActiveSupport::Notifications.subscribe('event.unione') do |*, payload|
  event = payload[:event]
  data = event.event_data
  Rails.logger.info("UniOne #{event.event_name}: #{data&.email} #{data&.status}")
end

Register the URL of the endpoint with webhook/set, e.g. https://example.com/unione/webhook.

Every section of the API is available on the client, see the SDK docs.

client = UniOne::Wrapper.client
info = client.system.info
puts info.accounting&.emails_sent

Besides the Action Mailer, mail can be sent through the API client directly. The client calls email/send with all of its options: templates, substitutions, metadata, tracking. Fields of the request and other examples: Ruby SDK docs.

Common = UniOne::Common::Model
Email = UniOne::Api::Email::Model

response = UniOne::Wrapper.client.email.send_email(Email::EmailSendRequest.new(
  message: Email::MessageObject.new(
    recipients: [
      Email::MessageObjectRecipientsItem.new(
        email: 'user@example.com',
        substitutions: {
          'CustomerId' => '12452',
          'to_name' => 'John Smith',
        }
      )
    ],
    body: Common::BodyObject.new(
      html: '<b>Hello, {{to_name}}</b>',
      plaintext: 'Hello, {{to_name}}'
    ),
    subject: 'UniOne test email ',
    from_email: 'email@example.com',
    from_name: 'John Smith'
  )
))
puts response.job_id

• Sends only to confirmed addresses: up to 10 per account.
• Up to 100 emails a day.
• The sandbox domain expires after 31 days; call domain/get-sandbox-domain again to get a new one.
• Works only with the account API key, not a project key.
• Not listed in domain/list; the other domain/* methods do not apply to it.

The sandbox is for development and testing. Do not use a sandbox domain as the sender in production.

1. domain/get-dns-records — returns the values for your DNS records.

2. Add these records at your DNS provider (the domain page of the control panel shows them too):

   Type	Host	Value
   TXT	@	the verification-record value (unione-validate-hash=…)
   TXT	<selector>._domainkey (the selector is on the domain page of the control panel, e.g. us)	v=DKIM1; k=rsa; p=<dkim>
   TXT	@	v=spf1 include:spf.unione.io ~all
   CNAME	_dmarc	the dmarc value

3. domain/validate-verification-record, then domain/validate-dkim.

4. domain/list — wait until the verification record is confirmed and DKIM is active.

5. Read from_email from your config, so switching from the sandbox needs no code change.

• Retries: set message.idempotence_key on sends that may be retried, so a repeated request does not send twice.
• Limits: up to 500 recipients and 10 MB per request; each attachment up to 7 MB.
• Body: always include body.html or body.plaintext.
• Delivery status: register a webhook (webhook/set) with a fast, idempotent HTTPS handler instead of polling.
• Defaults: keep the default unsubscribe footer and tracking; changing them requires UniOne support.
• Errors: retry 429 and 5xx with backoff; do not retry other errors unchanged.

• Send emails with Ruby and other integration guides
• Web API reference
• llms.txt for AI coding agents
• UniOne MCP server and agent setup
• Support

See AGENTS.md: how this package is generated from the OpenAPI spec, built, tested and released.