# Swoosh

[![hex.pm](https://img.shields.io/hexpm/v/swoosh.svg)](https://hex.pm/packages/swoosh)
[![hex.pm](https://img.shields.io/hexpm/dt/swoosh.svg)](https://hex.pm/packages/swoosh)
[![hex.pm](https://img.shields.io/hexpm/l/swoosh.svg)](https://hex.pm/packages/swoosh)
[![github.com](https://img.shields.io/github/last-commit/swoosh/swoosh.svg)](https://github.com/swoosh/swoosh)

Compose, deliver and test your emails easily in Elixir.

Swoosh comes with many adapters, including SendGrid, Mandrill, Mailgun, Postmark and SMTP.
See the full list of [adapters below](#adapters).

The complete documentation for Swoosh is [available online at HexDocs](https://hexdocs.pm/swoosh).

## Requirements

Elixir 1.16+ and Erlang OTP 26+

## Getting started

```elixir
# In your config/config.exs file
config :sample, Sample.Mailer,
  adapter: Swoosh.Adapters.Sendgrid,
  api_key: "SG.x.x"
```

```elixir
# In your application code
defmodule Sample.Mailer do
  use Swoosh.Mailer, otp_app: :sample
end
```

```elixir
defmodule Sample.UserEmail do
  import Swoosh.Email

  def welcome(user) do
    new()
    |> to({user.name, user.email})
    |> from({"Dr B Banner", "hulk.smash@example.com"})
    |> subject("Hello, Avengers!")
    |> html_body("<h1>Hello #{user.name}</h1>")
    |> text_body("Hello #{user.name}\n")
  end
end
```

```elixir
# In an IEx session
email = Sample.UserEmail.welcome(%{name: "Tony Stark", email: "tony.stark@example.com"})
Sample.Mailer.deliver(email)
```

```elixir
# Or in a Phoenix controller
defmodule Sample.UserController do
  use Phoenix.Controller
  alias Sample.UserEmail
  alias Sample.Mailer

  def create(conn, params) do
    user = create_user!(params)

    UserEmail.welcome(user) |> Mailer.deliver()
  end
end
```

See [`Swoosh.Mailer`](https://hexdocs.pm/swoosh/Swoosh.Mailer.html) for more
configuration options.

## Installation

- Add swoosh to your list of dependencies in `mix.exs`:

  ```elixir
  def deps do
    [{:swoosh, "~> 1.25"}]
  end
  ```

- (Optional-ish) Most adapters (non SMTP ones) use `Swoosh.ApiClient` to talk
  to the service provider. Swoosh comes with `Swoosh.ApiClient.Hackney` configured
  by default. If you want to use it, you just need to include
  [`Hackney`](https://hex.pm/packages/hackney) as a dependency of your app.

  Swoosh also accepts [`Finch`](https://hex.pm/packages/finch) and [`Req`](https://hex.pm/packages/req) out-of-the-box.
  See `Swoosh.ApiClient.Finch` and `Swoosh.ApiClient.Req` for details.

  If you need to integrate with another HTTP client, it's easy to define a new
  API client. Follow the `Swoosh.ApiClient` behaviour and configure Swoosh to
  use it:

  ```elixir
  config :swoosh, :api_client, MyApp.ApiClient
  ```

  But if you don't need `Swoosh.ApiClient`, you can disable it by setting the value
  to `false`:

  ```elixir
  config :swoosh, :api_client, false
  ```

  This is the case when you are using `Swoosh.Adapters.Local`,
  `Swoosh.Adapters.Test` and adapters that are SMTP based, that don't require
  an API client.

- (Optional) If you are using `Swoosh.Adapters.SMTP`,
  `Swoosh.Adapters.Sendmail` or `Swoosh.Adapters.AmazonSES`, you also need to
  add [`gen_smtp`](https://hex.pm/packages/gen_smtp) to your dependencies:

  ```elixir
  def deps do
    [
      {:swoosh, "~> 1.6"},
      {:gen_smtp, "~> 1.0"}
    ]
  end
  ```

## Adapters

Swoosh supports the most popular transactional email providers out of the box
and also has an SMTP adapter. Below is the list of the adapters currently
included:

| Provider                     | Swoosh adapter                                                                                                                  | Remarks          |
| ---------------------------- | ------------------------------------------------------------------------------------------------------------------------------- | ---------------- |
| SMTP                         | [Swoosh.Adapters.SMTP](https://hexdocs.pm/swoosh/Swoosh.Adapters.SMTP.html#content)                                             |                  |
| Mua                          | [Swoosh.Adapters.Mua](https://hexdocs.pm/swoosh/Swoosh.Adapters.Mua.html#content)                                               | SMTP alternative |
| SendGrid                     | [Swoosh.Adapters.Sendgrid](https://hexdocs.pm/swoosh/Swoosh.Adapters.Sendgrid.html#content)                                     |                  |
| Brevo                        | [Swoosh.Adapters.Brevo](https://hexdocs.pm/swoosh/Swoosh.Adapters.Brevo.html#content)                                           | Sendinblue       |
| Sendmail                     | [Swoosh.Adapters.Sendmail](https://hexdocs.pm/swoosh/Swoosh.Adapters.Sendmail.html#content)                                     |                  |
| Mandrill                     | [Swoosh.Adapters.Mandrill](https://hexdocs.pm/swoosh/Swoosh.Adapters.Mandrill.html#content)                                     |                  |
| Mailgun                      | [Swoosh.Adapters.Mailgun](https://hexdocs.pm/swoosh/Swoosh.Adapters.Mailgun.html#content)                                       |                  |
| MailerSend                   | [Swoosh.Adapters.Mailersend](https://hexdocs.pm/swoosh/Swoosh.Adapters.Mailersend.html#content)                                 |                  |
| Mailjet                      | [Swoosh.Adapters.Mailjet](https://hexdocs.pm/swoosh/Swoosh.Adapters.Mailjet.html#content)                                       |                  |
| MsGraph                      | [Swoosh.Adapters.MsGraph](https://hexdocs.pm/swoosh/Swoosh.Adapters.MsGraph.html#content)                                       |                  |
| Postmark                     | [Swoosh.Adapters.Postmark](https://hexdocs.pm/swoosh/Swoosh.Adapters.Postmark.html#content)                                     |                  |
| SparkPost                    | [Swoosh.Adapters.SparkPost](https://hexdocs.pm/swoosh/Swoosh.Adapters.SparkPost.html#content)                                   |                  |
| Amazon SES                   | [Swoosh.Adapters.AmazonSES](https://hexdocs.pm/swoosh/Swoosh.Adapters.AmazonSES.html#content)                                   |                  |
| Amazon SES                   | [Swoosh.Adapters.ExAwsAmazonSES](https://hexdocs.pm/swoosh/Swoosh.Adapters.ExAwsAmazonSES.html)                                 |                  |
| Customer.io                  | [Swoosh.Adapters.CustomerIO](https://hexdocs.pm/swoosh/Swoosh.Adapters.CustomerIO.html)                                         |                  |
| Dyn                          | [Swoosh.Adapters.Dyn](https://hexdocs.pm/swoosh/Swoosh.Adapters.Dyn.html#content)                                               |                  |
| Scaleway                     | [Swoosh.Adapters.Scaleway](https://hexdocs.pm/swoosh/Swoosh.Adapters.Scaleway.html#content)                                     |                  |
| SocketLabs                   | [Swoosh.Adapters.SocketLabs](https://hexdocs.pm/swoosh/Swoosh.Adapters.SocketLabs.html#content)                                 |                  |
| Gmail                        | [Swoosh.Adapters.Gmail](https://hexdocs.pm/swoosh/Swoosh.Adapters.Gmail.html#content)                                           |                  |
| MailPace                     | [Swoosh.Adapters.MailPace](https://hexdocs.pm/swoosh/Swoosh.Adapters.MailPace.html#content)                                     | OhMySMTP         |
| SMTP2GO                      | [Swoosh.Adapters.SMTP2GO](https://hexdocs.pm/swoosh/Swoosh.Adapters.SMTP2GO.html#content)                                       |                  |
| ProtonBridge                 | [Swoosh.Adapters.ProtonBridge](https://hexdocs.pm/swoosh/Swoosh.Adapters.ProtonBridge.html#content)                             |                  |
| Mailtrap                     | [Swoosh.Adapters.Mailtrap](https://hexdocs.pm/swoosh/Swoosh.Adapters.Mailtrap.html#content)                                     |                  |
| ZeptoMail                    | [Swoosh.Adapters.ZeptoMail](https://hexdocs.pm/swoosh/Swoosh.Adapters.ZeptoMail.html#content)                                   |                  |
| Postal                       | [Swoosh.Adapters.Postal](https://hexdocs.pm/swoosh/Swoosh.Adapters.Postal.html#content)                                         |                  |
| Lettermint                   | [Swoosh.Adapters.Lettermint](https://hexdocs.pm/swoosh/Swoosh.Adapters.Lettermint.html#content)                                 |                  |
| Resend                       | [Swoosh.Adapters.Resend](https://hexdocs.pm/swoosh/Swoosh.Adapters.Resend.html#content)                                         |                  |
| Azure Communication Services | [Swoosh.Adapters.AzureCommunicationServices](https://hexdocs.pm/swoosh/Swoosh.Adapters.AzureCommunicationServices.html#content) |                  |
| ------                       | **Below are not fully featured services**                                                                                       | ------           |
| Loops                        | [Swoosh.Adapters.Loops](https://hexdocs.pm/swoosh/Swoosh.Adapters.Loops.html#content)                                           |                  |
| PostUp                       | [Swoosh.Adapters.PostUp](https://hexdocs.pm/swoosh/Swoosh.Adapters.PostUp.html#content)                                         |                  |

Configure which adapter you want to use by updating your `config/config.exs`
file:

```elixir
config :sample, Sample.Mailer,
  adapter: Swoosh.Adapters.SMTP
  # adapter config (api keys, etc.)
```

Check the documentation of the adapter you want to use for more specific
configurations and instructions.

Adding new adapters is super easy and we are definitely looking for
contributions on that front. Get in touch if you want to help!

For local development and tests, these built-in adapters are also worth knowing:

- [`Swoosh.Adapters.Local`](https://hexdocs.pm/swoosh/Swoosh.Adapters.Local.html#content)
  stores emails locally so you can inspect them or use
  [`Plug.Swoosh.MailboxPreview`](https://hexdocs.pm/swoosh/Plug.Swoosh.MailboxPreview.html#content).
- [`Swoosh.Adapters.Test`](https://hexdocs.pm/swoosh/Swoosh.Adapters.Test.html#content)
  works with [`Swoosh.TestAssertions`](https://hexdocs.pm/swoosh/Swoosh.TestAssertions.html#content)
  in unit tests and basic integration tests.
- [`Swoosh.Adapters.Sandbox`](https://hexdocs.pm/swoosh/Swoosh.Adapters.Sandbox.html#content)
  is the async-safe testing adapter for feature, browser, and E2E tests where
  email delivery happens in separate processes.

### Third-party Adapters

Adapters for email providers not included by Swoosh, maintained by Elixir community members.

| Provider | Swoosh adapter                                                                | Remarks |
| -------- | ----------------------------------------------------------------------------- | ------- |
| Resend   | [Resend.Swoosh.Adapter](https://hexdocs.pm/resend/Resend.Swoosh.Adapter.html) |         |

## Recipient

The Recipient Protocol enables you to easily make your structs compatible
with Swoosh functions.

```elixir
defmodule MyUser do
  @derive {Swoosh.Email.Recipient, name: :name, address: :email}
  defstruct [:name, :email, :other_props]
end
```

Now you can directly pass `%MyUser{}` to `from`, `to`, `cc`, `bcc`, etc.
See `Swoosh.Email.Recipient` for more details.

## Async Emails

Swoosh does not make any special arrangements for sending emails in a
non-blocking manner. Opposite to some stacks, sending emails, talking
to third party apps, etc in Elixir do not block or interfere with other
requests, so you should resort to async emails only when necessary.

One simple way to deliver emails asynchronously is by leveraging Elixir's
standard library. First add a Task supervisor to your application root,
usually at `lib/my_app/application.ex`:

```elixir
def start(_, _) do
  children = [
    ...,
    # Before the endpoint
    {Task.Supervisor, name: MyApp.AsyncEmailSupervisor},
    MyApp.Endpoint
  ]

  Supervisor.start_link(children, strategy: :one_for_one)
end
```

Now, whenever you want to send an email:

```elixir
Task.Supervisor.start_child(MyApp.AsyncEmailSupervisor, fn ->
  %{name: "Tony Stark", email: "tony.stark@example.com"}
  |> Sample.UserEmail.welcome()
  |> Sample.Mailer.deliver()
end)
```

Please take a look at the official docs for
[Task](https://hexdocs.pm/elixir/Task.html) and
[Task.Supervisor](https://hexdocs.pm/elixir/Task.Supervisor.html) for further
options.

One of the downsides of sending email asynchronously is that failures won't
be reported to the user, who won't have an opportunity to try again immediately,
and tasks by default do not retry on errors. Therefore, if the email must be
delivered asynchronously, a safer solution would be to use a queue or job system.
Elixir's ecosystem has many
[job queue libraries](https://hex.pm/packages?search=job+queue&sort=recent_downloads).

- [Oban](https://hexdocs.pm/oban/Oban.html) is the current community favourite.
  It uses PostgreSQL for storage and coordination.
- [Exq](https://hexdocs.pm/exq/readme.html) uses Redis and is compatible with
  Resque / Sidekiq.

## Attachments

You can attach files to your email using the `Swoosh.Email.attachment/2`
function. Just give the path of your file as an argument and we will do the
rest. It also works with a `%Plug.Upload{}` struct, or a `%Swoosh.Attachment{}`
struct, which can be constructed using `Swoosh.Attachment.new` detailed here in
the [docs](https://hexdocs.pm/swoosh/Swoosh.Attachment.html#new/2).

All built-in adapters have support for attachments.

```elixir
new()
|> to("peter@example.com")
|> from({"Jarvis", "jarvis@example.com"})
|> subject("Invoice May")
|> text_body("Here is the invoice for your superhero services in May.")
|> attachment("/Users/jarvis/invoice-peter-may.pdf")
```

## Testing

In your `config/test.exs` file set your mailer's adapter to
`Swoosh.Adapters.Test` so that you can use the assertions provided by Swoosh in
`Swoosh.TestAssertions` module.

```elixir
defmodule Sample.UserTest do
  use ExUnit.Case, async: true

  import Swoosh.TestAssertions

  test "send email on user signup" do
    # Assuming `create_user` creates a new user then sends out a
    # `Sample.UserEmail.welcome` email
    user = create_user(%{username: "ironman", email: "tony.stark@example.com"})
    assert_email_sent Sample.UserEmail.welcome(user)
  end
end
```

For feature, browser, and E2E tests where email delivery happens outside the
test process tree, use
[`Swoosh.Adapters.Sandbox`](https://hexdocs.pm/swoosh/Swoosh.Adapters.Sandbox.html#content)
instead. Its module docs include setup instructions for standard ExUnit tests,
Phoenix integration, and browser-test helpers.

## Custom JSON Library

By default, Swoosh ships with required dependency `Jason`. In the future, we will change it to the builtin `JSON` module in Elixir 1.18+.
If you want to swap the default JSON library used by Swoosh, you can configure it in your `config/config.exs` file like this:

```elixir
config :swoosh, :json_library, JSON
```

In future major versions, `Jason` will be removed from the dependency list or become an optional dependency.

## Mailbox preview in the browser

Swoosh ships with a Plug that allows you to preview the emails in the local
(in-memory) mailbox. It's particularly convenient in development when you want
to check what your email will look like while testing the various flows of your
application.

For email to reach this mailbox you will need to set your `Mailer` adapter to
`Swoosh.Adapters.Local`:

```elixir
# in config/dev.exs
config :sample, MyApp.Mailer,
  adapter: Swoosh.Adapters.Local
```

In your Phoenix project you can `forward` directly to the plug
without spinning up a separate webserver, like this:

```elixir
# in web/router.ex
if Mix.env == :dev do
  scope "/dev" do
    pipe_through [:browser]

    forward "/mailbox", Plug.Swoosh.MailboxPreview
  end
end
```

You can also start a new server if your application does not depends on Phoenix:

```elixir
# in config/dev.exs
# to run the preview server alongside your app
# which may not have a web interface already
config :swoosh, serve_mailbox: true
```

```elixir
# in config/dev.exs
# to change the preview server port (4000 by default)
config :swoosh, serve_mailbox: true, preview_port: 4001
```

When using `serve_mailbox: true` make sure to have either `plug_cowboy` or
`bandit` as a dependency of your app.

```elixir
{:plug_cowboy, ">= 1.0.0"}
# or
{:bandit, ">= 1.0.0"}
```

And finally you can also use the following Mix task to start the mailbox
preview server independently:

```console
mix swoosh.mailbox.server
```

_Note_: the mailbox preview won't display emails
being sent from outside its own node. So if you are testing using an `IEx` session,
it's recommended to boot the application in the same session.
`iex -S mix phx.server` or `iex -S mix swoosh.mailbox.server` will do the trick.

If you are curious, this is how it the mailbox preview looks like:

![Plug.Swoosh.MailboxPreview](https://github.com/swoosh/swoosh/raw/main/images/mailbox-preview.png)

_Note_ : To show the preview we use the cdn-version of Tailwindcss. If you have set a `content-security-policy` you may have to add `https://cdn.tailwindcss.com` to `default-src` to have the correct make up.

The preview is also available as a JSON endpoint.

```sh
curl http://localhost:4000/dev/mailbox/json
```

### Production

Swoosh starts a memory storage process for local adapter by default. Normally
it does no harm being left around in production. However, if it is causing
problems, or you don't like having it around, it can be disabled like so:

```elixir
# config/prod.exs
config :swoosh, local: false
```

## Telemetry

The following events are emitted:

- `[:swoosh, :deliver, :start]`: occurs when `Mailer.deliver/2` begins.
- `[:swoosh, :deliver, :stop]`: occurs when `Mailer.deliver/2` completes.
- `[:swoosh, :deliver, :exception]`: occurs when `Mailer.deliver/2` throws an exception.
- `[:swoosh, :deliver_many, :start]`: occurs when `Mailer.deliver_many/2` begins.
- `[:swoosh, :deliver_many, :stop]`: occurs when `Mailer.deliver_many/2` completes.
- `[:swoosh, :deliver_many, :exception]`: occurs when `Mailer.deliver_many/2`
  throws an exception.

View [example in docs](https://hexdocs.pm/swoosh/Swoosh.Mailer.html#module-telemetry)

## Documentation

Documentation is written into the library, you will find it in the source code,
accessible from `iex` and of course, it all gets published to
[HexDocs](http://hexdocs.pm/swoosh).

## Contributing

We are grateful for any contributions. Before you submit an issue or a pull
request, remember to:

- Look at our [Contributing guidelines](CONTRIBUTING.md)
- Not use the issue tracker for help or support requests (try StackOverflow,
  IRC or Slack instead)
- Do a quick search in the issue tracker to make sure the issues hasn't been
  reported yet.
- Look and follow the [Code of Conduct](CODE_OF_CONDUCT.md). Be nice and have fun!

### Running tests

Clone the repo and fetch its dependencies:

```sh
git clone https://github.com/swoosh/swoosh.git
cd swoosh
mix deps.get
mix test
```

### Building docs

```sh
MIX_ENV=docs mix docs
```

## LICENSE

See [LICENSE](https://github.com/swoosh/swoosh/blob/main/LICENSE.txt)
