# `Bamboo.Interceptor`
[🔗](https://github.com/thoughtbot/bamboo/blob/main/lib/bamboo/interceptor.ex#L1)

Behaviour for creating an Interceptor.

An interceptor allows you to modify or block an email before it is sent. To
block an email, it must be marked as blocked with `Bamboo.Email.block/1`.

## Example

    defmodule Bamboo.DenyListInterceptor do
      @behaviour Bamboo.Interceptor
      @deny_list ["bar@foo.com"]

      def call(email) do
        if email.to in @deny_list do
          Bamboo.Email.block(email)
        else
          email
        end
      end
    end

# `call`

```elixir
@callback call(email :: Bamboo.Email.t()) :: Bamboo.Email.t()
```

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*Consult [api-reference.md](api-reference.md) for complete listing*