zerodrop

Email verification infrastructure for CI pipelines.

Send a verification email. Catch it at the edge. Get email.otp and email.magic_link back — auto-extracted, no regex, no Docker, no signup.

email = mail.wait_for_latest(inbox, timeout: 15)

email.otp        # => "123456" — auto-extracted
email.magic_link # => "https://..." — no regex needed

Documentation · GitHub · Status

Install

gem install zerodrop

Or in your Gemfile:

gem "zerodrop", group: :test

Zero runtime dependencies. Ruby 3.0+.

Quick start

require "zerodrop"

mail = ZeroDrop::Client.new
inbox = mail.generate_inbox
# => "swift-x7k29ab@zerodrop-sandbox.online"

# Trigger your app's email flow with the inbox address...

email = mail.wait_for_latest(inbox, timeout: 15)

email.subject    # => "Verify your email"
email.otp        # => "123456" — auto-extracted, no regex
email.magic_link # => "https://..." — auto-extracted

RSpec + Capybara

RSpec.describe "Signup email verification", type: :system do
  let(:mail) { ZeroDrop::Client.new }

  it "verifies the account via emailed OTP" do
    inbox = mail.generate_inbox

    visit "/signup"
    fill_in "Email", with: inbox
    fill_in "Password", with: "TestPassword123!"
    click_button "Create account"

    email = mail.wait_for_latest(inbox, timeout: 15)

    expect(email.otp).not_to be_nil
    fill_in "Code", with: email.otp
    click_button "Verify"

    expect(page).to have_current_path("/dashboard")
  end
end

Minitest

require "minitest/autorun"
require "zerodrop"

class SignupTest < Minitest::Test
  def test_email_verification
    mail = ZeroDrop::Client.new
    inbox = mail.generate_inbox

    # Trigger signup with inbox...

    email = mail.wait_for_latest(inbox, timeout: 15)

    refute_nil email.otp
    assert_match(/\A\d{6}\z/, email.otp)
  end
end

Email filtering

Filter by sender, subject, body, or extracted fields:

email = mail.wait_for_latest(
  inbox,
  timeout: 15,
  filter: ZeroDrop::Filter.new(
    from: "noreply@yourapp.com",
    subject: "Verify",
    has_otp: true
  )
)

All string filters are case-insensitive partial matches.

Magic link flows

email = mail.wait_for_latest(
  inbox,
  timeout: 15,
  filter: ZeroDrop::Filter.new(has_magic_link: true)
)

visit email.magic_link
expect(page).to have_current_path("/dashboard")

Parallel test runs

generate_inbox runs locally — no network request, no collisions:

# parallel_tests, flatware, turbo_tests — all safe
# Each process gets isolated inboxes automatically
inbox = mail.generate_inbox # unique every call

Error handling

begin
  email = mail.wait_for_latest(inbox, timeout: 15)
rescue ZeroDrop::TimeoutError
  # No email arrived — check your app is sending correctly
rescue ZeroDrop::AuthError
  # Invalid API key
rescue ZeroDrop::NetworkError => e
  # Transport failure — e.message includes status page link
end

Workspaces

mail = ZeroDrop::Client.new(api_key: ENV["ZERODROP_API_KEY"])

Self-hosted

mail = ZeroDrop::Client.new(base_url: "https://your-instance.yourdomain.com")

API

Method	Description
Client.new(api_key: nil, base_url: ...)	Create a client. No args = free sandbox mode.
#generate_inbox	Instant inbox address. No network request.
#fetch_latest(inbox, filter: nil)	Latest matching email or nil.
#wait_for_latest(inbox, timeout: 10, poll_interval: 2, filter: nil)	Block until email arrives.

Free vs Workspace

	Free	Workspace
Inbox generation	✓	✓
OTP auto-extraction	✓	✓
Magic link extraction	✓	✓
Email filtering	✓	✓
Email retention	30 min	Extended
Custom domains	✗	✓

Get a Workspace at zerodrop.dev

License

MIT