diff --git a/lib/gringotts/gateways/mercadopago.ex b/lib/gringotts/gateways/mercadopago.ex
new file mode 100644
index 00000000..5945374e
--- /dev/null
+++ b/lib/gringotts/gateways/mercadopago.ex
@@ -0,0 +1,368 @@
+defmodule Gringotts.Gateways.Mercadopago do
+  @moduledoc """
+  [mercadopago][home] gateway implementation.
+
+  For reference see [mercadopago documentation][docs].
+
+  The following features of mercadopago are implemented:
+
+  | Action                       | Method        |
+  | ------                       | ------        |
+  | Pre-authorize                | `authorize/3` |
+  | Capture                      | `capture/3`   |
+  | Purchase                     | `purchase/3`  |
+  | Reversal                     | `void/2`      |
+  | Refund                       | `refund/3`    |
+
+  [home]: https://www.mercadopago.com/
+  [docs]: https://www.mercadopago.com.ar/developers/en/api-docs/
+
+  ## The `opts` argument
+
+  Most `Gringotts` API calls accept an optional `keyword` list `opts` to supply
+  optional arguments for transactions with the mercadopag. The following keys are supported:
+
+  | Key                      | Remark                                                                                  |
+  | ----                     | ---                                                                                     |
+  | `email`                  | Email of the customer. Type - string                                                    |
+  | `order_id`               | Order id issued by the merchant. Type- integer                                          |
+  | `customer_id`            | Unique customer id issued by the gateway. For new customer it must skipped. Type- string|
+  | `order_type`             | `"mercadopago"` or `"mercadolibre"` as per the order. Type- string                      |
+  | `installments`           | No of installments for payment. Type- integer                                           |
+
+  ## Registering your mercadopago account at `Gringotts`
+
+  After [making an account on mercadopago][credentials], head to the credentials and find
+  your account "secrets" in the `Checkout Transparent`.
+
+  | Config parameter | MERCADOPAGO secret |
+  | -------          | ----               |
+  | `:access_token`  | **Access Token**   |
+  | `:public_key`    | **Public Key**     |
+
+  > Your Application config **must include the `[:public_key, :access_token]` field(s)** and would look
+  > something like this:
+  >
+  >     config :gringotts, Gringotts.Gateways.Mercadopago,
+  >         public_key: "your_secret_public_key"
+  >         access_token: "your_secret_access_token"
+
+  [credentials]: https://www.mercadopago.com/mlb/account/credentials?type=basic
+
+  ## Note
+
+  * mercadopago processes money in the subdivided units (like `cents` in case of
+    US Dollar).
+  * Also, there is no way to set the currency of the transaction via the API. It
+    is automatically set from the merchant's account. Hence, if you've
+    configured your mercadopago account to work in Chilean Peso (`CLP`), make
+    sure that the `amount` argument is always a `Money.t` struct with the `:CLP`
+    as currency.
+
+  ## Supported currencies and countries
+
+  mercadopago supports the currencies listed [here][currencies].
+
+  [currencies]: https://api.mercadopago.com/currencies
+
+  ## Following the examples
+
+  1. First, set up a sample application and configure it to work with MERCADOPAGO.
+  - You could do that from scratch by following our [Getting Started][gs] guide.
+      - To save you time, we recommend [cloning our example
+      repo][example] that gives you a pre-configured sample app ready-to-go.
+          + You could use the same config or update it the with your "secrets"
+          as described [above](#module-registering-your-mercadopago-account-at-gringotts).
+
+  [gs]: https://github.com/aviabird/gringotts/wiki/
+  [home]: https://www.mercadopago.com
+  [example]: https://github.com/aviabird/gringotts_payment
+  """
+
+  @base_url "https://api.mercadopago.com"
+  use Gringotts.Gateways.Base
+  alias Gringotts.CreditCard
+  # The Adapter module provides the `validate_config/1`
+  # Add the keys that must be present in the Application config in the
+  # `required_config` list
+  use Gringotts.Adapter, required_config: [:public_key, :access_token]
+
+  alias Gringotts.{CreditCard, Money, Response}
+
+  @doc """
+  Performs a (pre) Authorize operation.
+
+  The authorization validates the `card` details with the banking network,
+  places a hold on the transaction `amount` in the customer’s issuing bank.
+
+  mercadoapgo's `authorize` returns:
+  * `customer_id`, available in `Response.token` field and
+  * `authorization_id`, available in the `Response.id` field.
+
+  The `id` can be used to
+  * `capture/3` _an_ amount.
+  * `void/2` a pre-authorization.
+
+  ## Note
+
+  For a new customer, `customer_id` field should be `nil`. Otherwise it should
+  be provided.
+
+  ## Example
+
+  ### Authorization for new customer.
+
+    The following example shows how one would (pre) authorize a payment of 42
+    BRL on a sample `card`.
+
+      iex> amount = Money.new(42, :BRL)
+      iex> card = %Gringotts.CreditCard{first_name: "Lord", last_name: "Voldemort", number: "4509953566233704", year: 2099, month: 12, verification_code: "123", brand: "VISA"}
+      iex> opts = [email: "tommarvolo@riddle.com", order_id: 123123, payment_method_id: "visa"]
+      iex> {:ok, auth_result} = Gringotts.authorize(Gringotts.Gateways.Mercadopago, amount, card, opts)
+      iex> auth_result.id # This is the authorization ID
+      iex> auth_result.token # This is the customer ID/token
+
+  ### Authorization for old customer.
+
+    The following example shows how one would (pre) authorize a payment of 42
+    BRL on a sample `card`.
+
+      iex> amount = Money.new(42, :BRL)
+      iex> card = %Gringotts.CreditCard{first_name: "Hermione", last_name: "Granger", number: "4509953566233704", year: 2099, month: 12, verification_code: "123", brand: "VISA"}
+      iex> opts = [email: "hermione@granger.com", order_id: 123125, customer_id: "hermoine's customer id", payment_method_id: "visa"]
+      iex> {:ok, auth_result} = Gringotts.authorize(Gringotts.Gateways.Mercadopago, amount, card, opts)
+      iex> auth_result.id # This is the authorization ID
+      iex> auth_result.token # This is the customer ID/token
+  """
+  @spec authorize(Money.t(), CreditCard.t(), keyword) :: {:ok | :error, Response}
+  def authorize(amount, %CreditCard{} = card, opts) do
+    with {:ok, card_token} <- create_token(card, opts) do
+      {currency, value, exponent} = Money.to_integer(amount)
+      url_params = [access_token: opts[:config][:access_token]]
+
+      params = [
+        authorize_params(value, opts, card_token, false, card)
+      ]
+
+      body =
+        params
+        |> Enum.reduce(&Map.merge/2)
+        |> Poison.encode!()
+
+      commit(:post, "/v1/payments", body, opts, url_params)
+    end
+  end
+
+  @doc """
+  Captures a pre-authorized `amount`.
+  `amount` is transferred to the merchant account by mercadopago used in the
+  pre-authorization referenced by `payment_id`.
+  ## Note
+  mercadopago allows partial captures also. However, you can make a partial capture to a payment only **once**.
+  > The authorization will be valid for 7 days. If you do not capture it by that time, it will be cancelled.
+  > The specified amount can not exceed the originally reserved.
+  > If you do not specify the amount, all the reserved money is captured.
+  > In Argentina only available for Visa and American Express cards.
+  ## Example
+  The following example shows how one would (partially) capture a previously
+  authorized a payment worth 35 BRL by referencing the obtained authorization `id`.
+      iex> amount = Money.new(35, :BRL)
+      iex> {:ok, capture_result} = Gringotts.capture(Gringotts.Gateways.Mercadopago, auth_result.id, amount, opts)
+  """
+  @spec capture(String.t(), Money.t(), keyword) :: {:ok | :error, Response}
+  def capture(payment_id, amount, opts) do
+    {currency, value, exponent} = Money.to_integer(amount)
+    url_params = [access_token: opts[:config][:access_token]]
+    body = %{capture: true, transaction_amount: value} |> Poison.encode!()
+    commit(:put, "/v1/payments/#{payment_id}", body, opts, url_params)
+  end
+
+  @doc """
+  Transfers `amount` from the customer to the merchant.
+  mercadopago attempts to process a purchase on behalf of the customer, by
+  debiting `amount` from the customer's account by charging the customer's
+  `card`.
+  ## Example
+  The following example shows how one would process a payment worth 42 BRL in
+  one-shot, without (pre) authorization.
+      iex> amount = Money.new(42, :BRL)
+      iex> card = %Gringotts.CreditCard{first_name: "Harry", last_name: "Potter", number: "4200000000000000", year: 2099, month: 12, verification_code:  "123", brand: "VISA"}
+      iex> {:ok, purchase_result} = Gringotts.purchase(Gringotts.Gateways.Mercadopago, amount, card, opts)
+      iex> purchase_result.token # This is the customer ID/token
+  """
+  @spec purchase(Money.t(), CreditCard.t(), keyword) :: {:ok | :error, Response}
+  def purchase(amount, %CreditCard{} = card, opts) do
+    with {:ok, card_token} <- create_token(card, opts) do
+      {currency, value, exponent} = Money.to_integer(amount)
+      url_params = [access_token: opts[:config][:access_token]]
+
+      body = value |> authorize_params(opts, card_token, true, card) |> Poison.encode!()
+      commit(:post, "/v1/payments", body, opts, url_params)
+    end
+  end
+
+  @doc """
+  Voids the referenced payment.
+  This method attempts a reversal of a previous transaction referenced by
+  `payment_id`.
+  > As a consequence, the customer will never see any booking on his statement.
+  ## Note
+  > Only pending or in_process payments can be cancelled.
+  > Cancelled coupon payments, deposits and/or transfers will be deposited in the buyer’s Mercadopago account.
+  ## Example
+  The following example shows how one would void a previous (pre)
+  authorization. Remember that our `capture/3` example only did a partial
+  capture.
+      iex> {:ok, void_result} = Gringotts.void(Gringotts.Gateways.Mercadopago, auth_result.id, opts)
+  """
+  @spec void(String.t(), keyword) :: {:ok | :error, Response}
+  def void(payment_id, opts) do
+    # url = "#{@base_url}/v1/payments/#{payment_id}?access_token=#{opts[:config][:access_token]}"
+    url_params = [access_token: opts[:config][:access_token]]
+    body = %{status: "cancelled"} |> Poison.encode!()
+    commit(:put, "/v1/payments/#{payment_id}", body, opts, url_params)
+  end
+
+  @doc """
+  Refunds the `amount` to the customer's account with reference to a prior transfer.
+  mercadopago processes a full or partial refund worth `amount`, referencing a
+  previous `purchase/3` or `capture/3`.
+  ## Note
+  > You must have enough available money in your account so you can refund the payment amount successfully. Otherwise, you'll get a 400 Bad Request error.
+  > You can refund a payment within 90 days after it was accredited.
+  > You can only refund approved payments.
+  > You can perform up to 20 partial refunds in one payment.
+  ## Example
+  The following example shows how one would (completely) refund a previous
+  purchase (and similarily for captures).
+      iex> amount = Money.new(35, :BRL)
+      iex> {:ok, refund_result} = Gringotts.refund(Gringotts.Gateways.Mercadopago, purchase_result.id, amount)
+  """
+  @spec refund(Money.t(), String.t(), keyword) :: {:ok | :error, Response}
+  def refund(amount, payment_id, opts) do
+    {currency, value, exponent} = Money.to_integer(amount)
+
+    # url =
+    # "#{@base_url}/v1/payments/#{payment_id}/refunds?access_token=#{opts[:config][:access_token]}"
+    url_params = [access_token: opts[:config][:access_token]]
+    body = %{amount: value} |> Poison.encode!()
+    commit(:post, "/v1/payments/#{payment_id}/refunds", body, opts, url_params)
+  end
+
+  ###############################################################################
+  #                                PRIVATE METHODS                              #
+  ###############################################################################
+
+  # Makes the request to mercadopago's network.
+  # For consistency with other gateway implementations, make your (final)
+  # network request in here, and parse it using another private method called
+  # `respond`.
+  @spec commit(atom, String.t(), String.t(), keyword, keyword) :: {:ok | :error, Response.t()}
+  defp commit(method, path, body, opts, url_params) do
+    headers = [{"content-type", "application/json"}, {"accept", "application/json"}]
+    url = "#{@base_url}#{path}"
+
+    res =
+      HTTPoison.request(
+        method,
+        url,
+        body,
+        headers,
+        opts ++ [params: [access_token: opts[:config][:access_token]]]
+      )
+
+    respond(res, opts)
+  end
+
+  defp token_params(%CreditCard{} = card) do
+    %{
+      expirationYear: card.year,
+      expirationMonth: card.month,
+      cardNumber: card.number,
+      securityCode: card.verification_code,
+      cardholder: %{name: CreditCard.full_name(card)}
+    }
+  end
+
+  defp create_token(%CreditCard{} = card, opts) do
+    url_params = [public_key: opts[:config][:public_key]]
+
+    body =
+      card
+      |> token_params()
+      |> Poison.encode!()
+
+    {state, res} = commit(:post, "/v1/card_tokens/#{opts[:customer_id]}", body, opts, url_params)
+
+    case state do
+      :error -> {state, res}
+      _ -> {state, res.id}
+    end
+  end
+
+  defp authorize_params(value, opts, token_id, capture, %CreditCard{} = card) do
+    %{
+      installments: opts[:installments] || 1,
+      transaction_amount: value,
+      payment_method_id: String.downcase(card.brand),
+      token: token_id,
+      capture: capture,
+      payer: %{
+        email: opts[:email]
+      }
+    }
+  end
+
+  defp customer_params(%CreditCard{} = card, customer_id, opts) do
+    %{
+      payer: %{
+        type: "customer",
+        id: customer_id,
+        first_name: card.first_name,
+        last_name: card.last_name
+      },
+      order: %{
+        type: opts[:order_type],
+        id: opts[:order_id]
+      }
+    }
+  end
+
+  defp success_body(body, status_code, opts) do
+    %Response{
+      success: true,
+      id: body["id"],
+      token: opts[:customer_id],
+      status_code: status_code,
+      message: body["status"]
+    }
+  end
+
+  defp error_body(body, status_code, opts) do
+    %Response{
+      success: false,
+      token: opts[:customer_id],
+      status_code: status_code,
+      message: body["message"]
+    }
+  end
+
+  defp respond({:ok, %HTTPoison.Response{body: body, status_code: status_code}}, opts) do
+    body = body |> Poison.decode!()
+
+    case body["cause"] do
+      nil -> {:ok, success_body(body, status_code, opts)}
+      _ -> {:error, error_body(body, status_code, opts)}
+    end
+  end
+
+  defp respond({:error, %HTTPoison.Error{} = error}, _) do
+    {
+      :error,
+      Response.error(
+        reason: "network related failure",
+        message: "HTTPoison says '#{error.reason}' [ID: #{error.id || "nil"}]"
+      )
+    }
+  end
+end
diff --git a/test/gateways/mercadopago_test.exs b/test/gateways/mercadopago_test.exs
new file mode 100644
index 00000000..3226712f
--- /dev/null
+++ b/test/gateways/mercadopago_test.exs
@@ -0,0 +1,234 @@
+defmodule Gringotts.Gateways.MercadopagoTest do
+  use ExUnit.Case, async: false
+  alias Gringotts.Gateways.MercadopagoMock, as: MockResponse
+  alias Gringotts.{CreditCard, FakeMoney}
+  alias Gringotts.Gateways.Mercadopago, as: Merc
+
+  import Mock
+
+  @auth %{name: "64jKa6NA", transaction_key: "4vmE338dQmAN6m7B"}
+  @card %CreditCard{
+    number: "5424000000000015",
+    month: 12,
+    year: 2099,
+    verification_code: 999,
+    brand: "visa"
+  }
+
+  @bad_card %CreditCard{
+    number: "123",
+    month: 10,
+    year: 2010,
+    verification_code: 123,
+    brand: "visa"
+  }
+
+  @amount FakeMoney.new("2.99", :USD)
+
+  @opts [
+    config: @auth,
+    ref_id: "123456",
+    order: %{invoice_number: "INV-12345", description: "Product Description"},
+    lineitems: %{
+      item_id: "1",
+      name: "vase",
+      description: "Cannes logo",
+      quantity: 18,
+      unit_price: FakeMoney.new("53.82", :USD)
+    },
+    tax: %{name: "VAT", amount: FakeMoney.new("0.1", :EUR), description: "Value Added Tax"},
+    shipping: %{
+      name: "SAME-DAY-DELIVERY",
+      amount: FakeMoney.new("0.56", :EUR),
+      description: "Zen Logistics"
+    },
+    duty: %{
+      name: "import_duty",
+      amount: FakeMoney.new("0.25", :EUR),
+      description: "Upon import of goods"
+    }
+  ]
+  @opts_refund [
+    config: @auth,
+    ref_id: "123456",
+    payment: %{card: %{number: "5424000000000015", year: 2099, month: 12}}
+  ]
+
+  @opts_store [
+    config: @auth,
+    profile: %{
+      merchant_customer_id: "123456",
+      description: "Profile description here",
+      email: "customer-profile-email@here.com"
+    },
+    customer_type: "individual",
+    validation_mode: "testMode"
+  ]
+  @opts_store_without_validation [
+    config: @auth,
+    profile: %{
+      merchant_customer_id: "123456",
+      description: "Profile description here",
+      email: "customer-profile-email@here.com"
+    }
+  ]
+
+  @opts_store_no_profile [
+    config: @auth
+  ]
+  @opts_refund [
+    config: @auth,
+    ref_id: "123456",
+    payment: %{card: %{number: "5424000000000015", year: 2099, month: 12}}
+  ]
+  @opts_refund_bad_payment [
+    config: @auth,
+    ref_id: "123456",
+    payment: %{card: %{number: "123", year: 2099, month: 12}}
+  ]
+  @opts_store [
+    config: @auth,
+    profile: %{
+      merchant_customer_id: "123456",
+      description: "Profile description here",
+      email: "customer-profile-email@here.com"
+    }
+  ]
+  @opts_store_no_profile [
+    config: @auth
+  ]
+  @opts_customer_profile [
+    config: @auth,
+    customer_profile_id: "1814012002",
+    validation_mode: "testMode",
+    customer_type: "individual"
+  ]
+  @opts_customer_profile_args [
+    config: @auth,
+    customer_profile_id: "1814012002"
+  ]
+
+  @refund_id "60036752756"
+  @void_id "60036855217"
+  @void_invalid_id "60036855211"
+  @unstore_id "1813991490"
+  @capture_id "60036752756"
+  @capture_invalid_id "60036855211"
+
+  @refund_id "60036752756"
+  @void_id "60036855217"
+  @unstore_id "1813991490"
+
+  describe "purchase" do
+    test "successful response with right params" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options ->
+          MockResponse.successful_purchase_response()
+        end do
+        assert {:ok, _response} = Merc.purchase(@amount, @card, @opts)
+      end
+    end
+
+    test "with bad card" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options ->
+          MockResponse.bad_card_purchase_response()
+        end do
+        assert {:error, _response} = Merc.purchase(@amount, @bad_card, @opts)
+      end
+    end
+  end
+
+  describe "authorize" do
+    test "successful response with right params" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options ->
+          MockResponse.successful_authorize_response()
+        end do
+        assert {:ok, _response} = Merc.authorize(@amount, @card, @opts)
+      end
+    end
+
+    test "with bad card" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options ->
+          MockResponse.bad_card_purchase_response()
+        end do
+        assert {:error, _response} = Merc.authorize(@amount, @bad_card, @opts)
+      end
+    end
+  end
+
+  describe "capture" do
+    test "successful response with right params" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options ->
+          MockResponse.successful_capture_response()
+        end do
+        assert {:ok, _response} = Merc.capture(@capture_id, @amount, @opts)
+      end
+    end
+
+    test "with bad transaction id" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options -> MockResponse.bad_id_capture() end do
+        assert {:error, _response} = Merc.capture(@capture_invalid_id, @amount, @opts)
+      end
+    end
+  end
+
+  describe "refund" do
+    test "successful response with right params" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options ->
+          MockResponse.successful_refund_response()
+        end do
+        assert {:ok, _response} = Merc.refund(@amount, @refund_id, @opts_refund)
+      end
+    end
+
+    test "bad payment params" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options -> MockResponse.bad_card_refund() end do
+        assert {:error, _response} = Merc.refund(@amount, @refund_id, @opts_refund_bad_payment)
+      end
+    end
+
+    test "debit less than refund amount" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options ->
+          MockResponse.debit_less_than_refund()
+        end do
+        assert {:error, _response} = Merc.refund(@amount, @refund_id, @opts_refund)
+      end
+    end
+  end
+
+  describe "void" do
+    test "successful response with right params" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options -> MockResponse.successful_void() end do
+        assert {:ok, _response} = Merc.void(@void_id, @opts)
+      end
+    end
+
+    test "with bad transaction id" do
+      with_mock HTTPoison,
+        request: fn _method, _url, _body, _headers, _options ->
+          MockResponse.void_non_existent_id()
+        end do
+        assert {:error, _response} = Merc.void(@void_invalid_id, @opts)
+      end
+    end
+  end
+
+  test "network error type non existent domain" do
+    with_mock HTTPoison,
+      request: fn _method, _url, _body, _headers, _options ->
+        MockResponse.netwok_error_non_existent_domain()
+      end do
+      assert {:error, response} = Merc.purchase(@amount, @card, @opts)
+      assert response.message == "HTTPoison says 'nxdomain' [ID: nil]"
+    end
+  end
+end
diff --git a/test/integration/gateways/mercadopago_test.exs b/test/integration/gateways/mercadopago_test.exs
new file mode 100644
index 00000000..95da249a
--- /dev/null
+++ b/test/integration/gateways/mercadopago_test.exs
@@ -0,0 +1,241 @@
+defmodule Gringotts.Integration.Gateways.MercadopagoTest do
+  # Integration tests for the Mercadopago
+
+  use ExUnit.Case, async: true
+  alias Gringotts.Gateways.Mercadopago, as: Gateway
+
+  alias Gringotts.{
+    CreditCard,
+    FakeMoney
+  }
+
+  @moduletag integration: true
+
+  @amount FakeMoney.new(45, :BRL)
+  @sub_amount FakeMoney.new(30, :BRL)
+  @config [
+    access_token: "TEST-4543588471539213-040810-f4f850f89480ee1bd56e05a9aa0d6210-543713181",
+    public_key: "TEST-4508ea76-c56b-436a-9213-57934dfb2d86"
+  ]
+  @bad_config [
+    access_token: "TEST-4543588471539213-111111-f4f850f89480ee1bd56e05a9aa0d6210-543713181",
+    public_key: "TEST-4508ea76-c56b-436a-9999-57934dfb2d86"
+  ]
+  @good_card %CreditCard{
+    first_name: "Hermoine",
+    last_name: "Grangerr",
+    number: "4509953566233704",
+    year: 2030,
+    month: 07,
+    verification_code: "123",
+    brand: "VISA"
+  }
+
+  @bad_card %CreditCard{
+    first_name: "Hermoine",
+    last_name: "Grangerr",
+    number: "4509953566233704",
+    year: 2000,
+    month: 07,
+    verification_code: "123",
+    brand: "VISA"
+  }
+
+  @good_opts [
+    email: "hermoine@granger.com",
+    order_id: 123_126,
+    customer_id: "311211654-YrXF6J0QikpIWX",
+    config: @config,
+    installments: 1,
+    order_type: "mercadopago"
+  ]
+  @bad_opts [
+    email: "hermoine@granger.com",
+    config: @bad_config
+  ]
+
+  @new_cutomer_good_opts [
+    order_id: 123_126,
+    config: @config,
+    installments: 1,
+    order_type: "mercadopago"
+  ]
+  @new_cutomer_bad_opts [
+    config: @bad_config,
+    order_id: 123_127
+  ]
+
+  def new_email_opts(good) do
+    no1 = 100_000 |> :rand.uniform() |> to_string
+    no2 = 100_000 |> :rand.uniform() |> to_string
+    no3 = 100_000 |> :rand.uniform() |> to_string
+    email = "hp" <> no1 <> no2 <> no3 <> "@potter.com"
+
+    case good do
+      true -> @new_cutomer_good_opts ++ [email: email]
+      _ -> @new_cutomer_bad_opts ++ [email: email]
+    end
+  end
+
+  describe "[authorize] old customer" do
+    test "old customer with good_opts and good_card" do
+      assert {:ok, response} = Gateway.authorize(@amount, @good_card, @good_opts)
+      assert response.success == true
+      assert response.status_code == 201
+    end
+
+    test "old customer with good_opts and bad_card" do
+      assert {:error, response} = Gateway.authorize(@amount, @bad_card, @good_opts)
+      assert response.success == false
+      assert response.status_code == 400
+    end
+  end
+
+  setup do
+    [opts: new_email_opts(true)]
+  end
+
+  describe "[authorize] new customer" do
+    test "new cutomer with good_opts and good_card", %{opts: opts} do
+      assert {:ok, response} = Gateway.authorize(@amount, @good_card, opts)
+      assert response.success == true
+      assert response.status_code == 201
+    end
+
+    test "new customer with good_opts and bad_card", %{opts: opts} do
+      assert {:error, response} = Gateway.authorize(@amount, @bad_card, opts)
+      assert response.success == false
+      assert response.status_code == 400
+    end
+  end
+
+  describe "[capture]" do
+    test "capture success" do
+      {:ok, response} = Gateway.authorize(@sub_amount, @good_card, @good_opts)
+      {:ok, response} = Gateway.capture(response.id, @sub_amount, @good_opts)
+      assert response.success == true
+      assert response.status_code == 200
+    end
+
+    test "capture invalid payment_id" do
+      {:ok, response} = Gateway.authorize(@sub_amount, @good_card, @good_opts)
+      id = response.id + 1
+      {:error, response} = Gateway.capture(id, @sub_amount, @good_opts)
+      assert response.success == false
+      assert response.status_code == 404
+    end
+
+    test "extra amount capture" do
+      {:ok, response} = Gateway.authorize(@sub_amount, @good_card, @good_opts)
+      {:error, response} = Gateway.capture(response.id, @amount, @good_opts)
+      assert response.success == false
+      assert response.status_code == 400
+    end
+  end
+
+  describe "[void]" do
+    test "void success" do
+      {:ok, response} = Gateway.authorize(@sub_amount, @good_card, @good_opts)
+      {:ok, response} = Gateway.void(response.id, @good_opts)
+      assert response.success == true
+      assert response.status_code == 200
+    end
+
+    test "invalid payment_id" do
+      {:ok, response} = Gateway.authorize(@sub_amount, @good_card, @good_opts)
+      id = response.id + 1
+      {:error, response} = Gateway.void(id, @good_opts)
+      assert response.success == false
+      assert response.status_code == 404
+    end
+  end
+
+  describe "[purchase]" do
+    test "old customer with good_opts and good_card" do
+      assert {:ok, response} = Gateway.purchase(@amount, @good_card, @good_opts)
+      assert response.success == true
+      assert response.status_code == 201
+    end
+
+    test "old customer with good_opts and bad_card" do
+      assert {:error, response} = Gateway.purchase(@amount, @bad_card, @good_opts)
+      assert response.success == false
+      assert response.status_code == 400
+    end
+
+    test "old customer with bad_opts and good_card" do
+      assert {:error, response} = Gateway.purchase(@amount, @good_card, @bad_opts)
+      assert response.success == false
+      # We expect 401-Unauthorized when bad access_token is provided.
+      # But mergadopago API returns 404 with message "invalid token" instead.
+      # So that is what we check
+      assert response.status_code == 404
+      assert response.message == "invalid_token"
+    end
+
+    test "old customer with bad_opts and bad_card" do
+      assert {:error, response} = Gateway.purchase(@amount, @bad_card, @bad_opts)
+      assert response.success == false
+      assert response.status_code == 400
+      assert response.message == "invalid expiration_year"
+    end
+
+    test "new cutomer with good_opts and good_card" do
+      opts = new_email_opts(true)
+      assert {:ok, response} = Gateway.purchase(@amount, @good_card, opts)
+      assert response.success == true
+      assert response.status_code == 201
+    end
+
+    test "new customer with good_opts and bad_card" do
+      opts = new_email_opts(true)
+      assert {:error, response} = Gateway.purchase(@amount, @bad_card, opts)
+      assert response.success == false
+      assert response.status_code == 400
+      assert response.message == "invalid expiration_year"
+    end
+
+    test "new customer with bad_opts and good_card" do
+      opts = new_email_opts(false)
+      assert {:error, response} = Gateway.purchase(@amount, @good_card, opts)
+      assert response.success == false
+      # We expect 401-Unauthorized when bad access_token is provided.
+      # But mergadopago API returns 404 with message "invalid token" instead.
+      # So that is what we check
+      assert response.status_code == 404
+      assert response.message == "invalid_token"
+    end
+
+    test "new customer with bad_opts and bad_card" do
+      opts = new_email_opts(false)
+      assert {:error, response} = Gateway.purchase(@amount, @bad_card, opts)
+      assert response.success == false
+      assert response.status_code == 400
+      assert response.message == "invalid expiration_year"
+    end
+  end
+
+  describe "[refund]" do
+    test "refund success" do
+      {:ok, response} = Gateway.purchase(@sub_amount, @good_card, @good_opts)
+      {:ok, response} = Gateway.refund(@sub_amount, response.id, @good_opts)
+      assert response.success == true
+      assert response.status_code == 201
+    end
+
+    test "invalid payment_id" do
+      {:ok, response} = Gateway.purchase(@sub_amount, @good_card, @good_opts)
+      id = response.id + 1
+      {:error, response} = Gateway.refund(@sub_amount, id, @good_opts)
+      assert response.success == false
+      assert response.status_code == 404
+    end
+
+    test "extra amount refund" do
+      {:ok, response} = Gateway.purchase(@sub_amount, @good_card, @good_opts)
+      {:error, response} = Gateway.refund(@amount, response.id, @good_opts)
+      assert response.success == false
+      assert response.status_code == 400
+    end
+  end
+end
diff --git a/test/support/mocks/mercadopago_mock.ex b/test/support/mocks/mercadopago_mock.ex
new file mode 100644
index 00000000..f1c18779
--- /dev/null
+++ b/test/support/mocks/mercadopago_mock.ex
@@ -0,0 +1,226 @@
+defmodule Gringotts.Gateways.MercadopagoMock do
+  @base_url "https://api.mercadopago.com"
+
+  @moduledoc false
+  # purchase mock response
+  def successful_purchase_response do
+    {:ok,
+     %HTTPoison.Response{
+       #       body: {"id": 20359978, "date_created": "2019-07-10T10:47:58.000-04:00", "date_approved": "2019-07-10T10:47:58.000-04:00", "date_last_updated": "2019-07-10T10:47:58.000-04:00", "date_of_expiration": null, "money_release_date": "2019-07-24T10:47:58.000-04:00", "operation_type": "regular_payment", "issuer_id": "25", "payment_method_id": "visa", "payment_type_id": "credit_card", "status": "approved"},
+       body:
+         "{\"id\":24687003,\"date_created\":\"2019-07-10T03:23:38.000-04:00\",\"date_approved\":\"2019-07-10T03:23:38.000-04:00\",\"date_last_updated\":\"2019-07-10T03:23:38.000-04:00\",\"date_of_expiration\":null,\"money_release_date\":\"2020-04-14T03:23:38.000-04:00\",\"operation_type\":\"regular_payment\",\"issuer_id\":\"25\",\"payment_method_id\":\"visa\",\"payment_type_id\":\"credit_card\",\"status\":\"approved\",\"status_detail\":\"accredited\",\"currency_id\":\"BRL\",\"description\":null,\"live_mode\":false,\"sponsor_id\":null,\"authorization_code\":null,\"money_release_schema\":null,\"taxes_amount\":0,\"counter_currency\":null,\"shipping_amount\":0,\"pos_id\":null,\"store_id\":null,\"integrator_id\":null,\"platform_id\":null,\"corporation_id\":null,\"collector_id\":543713181,\"payer\":{\"first_name\":\"Test\",\"last_name\":\"Test\",\"email\":\"test_user_80507629@testuser.com\",\"identification\":{\"number\":\"32659430\",\"type\":\"DNI\"},\"phone\":{\"area_code\":\"01\",\"number\":\"1111-1111\",\"extension\":\"\"},\"type\":\"registered\",\"entity_type\":null,\"id\":\"546439110\"},\"marketplace_owner\":null,\"metadata\":{},\"additional_info\":{\"available_balance\":null,\"nsu_processadora\":null},\"order\":{},\"external_reference\":null,\"transaction_amount\":4500,\"transaction_amount_refunded\":0,\"coupon_amount\":0,\"differential_pricing_id\":null,\"deduction_schema\":null,\"installments\":1,\"transaction_details\":{\"payment_method_reference_id\":null,\"net_received_amount\":4275.45,\"total_paid_amount\":4500,\"overpaid_amount\":0,\"external_resource_url\":null,\"installment_amount\":4500,\"financial_institution\":null,\"payable_deferral_period\":null,\"acquirer_reference\":null},\"fee_details\":[{\"type\":\"mercadopago_fee\",\"amount\":224.55,\"fee_payer\":\"collector\"}],\"captured\":true,\"binary_mode\":false,\"call_for_authorize_id\":null,\"statement_descriptor\":\"ASHISHSINGH\",\"card\":{\"id\":null,\"first_six_digits\":\"450995\",\"last_four_digits\":\"3704\",\"expiration_month\":7,\"expiration_year\":2030,\"date_created\":\"2020-04-14T03:23:38.000-04:00\",\"date_last_updated\":\"2020-04-14T03:23:38.000-04:00\",\"cardholder\":{\"name\":\"Hermoine Grangerr\",\"identification\":{\"number\":null,\"type\":null}}},\"notification_url\":null,\"refunds\":[],\"processing_mode\":\"aggregator\",\"merchant_account_id\":null,\"acquirer\":null,\"merchant_number\":null,\"acquirer_reconciliation\":[]}",
+       headers: [
+         {"Content-Type", "application/json;charset=UTF-8"},
+         {"Transfer-Encoding", "chunked"},
+         {"Connection", "keep-alive"},
+         {"Cache-Control", "max-age=0"},
+         {"ETag", "6d6d1b4a79c868769305de14687c4d6d"},
+         {"Vary", "Accept,Accept-Encoding,Accept-Encoding"},
+         {"X-Caller-Id", "543713181"},
+         {"X-Response-Status", "approved/accredited"},
+         {"X-Site-Id", "MLB"},
+         {"X-Content-Type-Options", "nosniff"},
+         {"X-Request-Id", "59257cf5-6cc6-4afc-b310-e36e412ad4fc"},
+         {"X-XSS-Protection", "1; mode=block"},
+         {"Strict-Transport-Security", "max-age=16070400; includeSubDomains; preload"},
+         {"Access-Control-Allow-Origin", "*"},
+         {"Access-Control-Allow-Headers", "Content-Type"},
+         {"Access-Control-Allow-Methods", "PUT, GET, POST, DELETE, OPTIONS"},
+         {"Access-Control-Max-Age", "86400"},
+         {"Timing-Allow-Origin", "*"},
+         {"Date", "Mon, 25 Dec 2017 14:17:56 GMT"}
+       ],
+       request_url: "#{@base_url}/v1/payments",
+       status_code: 200
+     }}
+  end
+
+  def bad_card_purchase_response do
+    {:error,
+     %HTTPoison.Error{
+       reason: "Bad Card for Purchase",
+       id: 1_234_567
+     }}
+  end
+
+  def bad_amount_purchase_response do
+    {:error,
+     %HTTPoison.Response{
+       body:
+         "{\"id\": 20359978, \"date_created\": \"2019-07-10T10:47:58.000-04:00\", \"date_approved\": \"2019-07-10T10:47:58.000-04:00\", \"date_last_updated\": \"2019-07-10T10:47:58.000-04:00\", \"date_of_expiration\": null, \"money_release_date\": \"2019-07-24T10:47:58.000-04:00\", \"operation_type\": \"regular_payment\", \"issuer_id\": \"25\", \"payment_method_id\": \"visa\", \"payment_type_id\": \"credit_card\", \"status\": \"approved\"}",
+       headers: [
+         {"Content-Type", "application/json"},
+         {"Access-Control-Allow-Origin", "*"},
+         {"Access-Control-Allow-Methods", "PUT,OPTIONS,POST,GET"},
+         {"Date", "Mon, 25 Dec 2017 14:17:56 GMT"}
+       ],
+       request_url: "#{@base_url}/v1/payments",
+       status_code: 200
+     }}
+  end
+
+  # authorize mock response
+  def successful_authorize_response do
+    {:ok,
+     %HTTPoison.Response{
+       body:
+         "{\"id\": 20359978, \"date_created\": \"2019-07-10T10:47:58.000-04:00\", \"date_approved\": \"2019-07-10T10:47:58.000-04:00\", \"date_last_updated\": \"2019-07-10T10:47:58.000-04:00\", \"date_of_expiration\": null, \"money_release_date\": \"2019-07-24T10:47:58.000-04:00\", \"operation_type\": \"regular_payment\", \"issuer_id\": \"25\", \"payment_method_id\": \"visa\", \"payment_type_id\": \"credit_card\", \"status\": \"approved\"}",
+       headers: [
+         {"Content-Type", "application/json"},
+         {"Access-Control-Allow-Origin", "*"},
+         {"Access-Control-Allow-Methods", "PUT,OPTIONS,POST,GET"},
+         {"Date", "Mon, 25 Dec 2017 14:17:56 GMT"}
+       ],
+       request_url: "#{@base_url}/v1/payments",
+       status_code: 200
+     }}
+  end
+
+  def bad_card_authorize_response do
+    {:ok,
+     %HTTPoison.Response{
+       body:
+         "{\"id\": 20359978, \"date_created\": \"2019-07-10T10:47:58.000-04:00\", \"date_approved\": \"2019-07-10T10:47:58.000-04:00\", \"date_last_updated\": \"2019-07-10T10:47:58.000-04:00\", \"date_of_expiration\": null, \"money_release_date\": \"2019-07-24T10:47:58.000-04:00\", \"operation_type\": \"regular_payment\", \"issuer_id\": \"25\", \"payment_method_id\": \"visa\", \"payment_type_id\": \"credit_card\", \"status\": \"approved\"}",
+       headers: [
+         {"Content-Type", "application/json"},
+         {"Access-Control-Allow-Origin", "*"},
+         {"Access-Control-Allow-Methods", "PUT,OPTIONS,POST,GET"},
+         {"Date", "Mon, 25 Dec 2017 14:17:56 GMT"}
+       ],
+       request_url: "#{@base_url}/v1/payments",
+       status_code: 200
+     }}
+  end
+
+  def bad_amount_authorize_response do
+    {:ok,
+     %HTTPoison.Response{
+       body:
+         "{\"id\": 20359978, \"date_created\": \"2019-07-10T10:47:58.000-04:00\", \"date_approved\": \"2019-07-10T10:47:58.000-04:00\", \"date_last_updated\": \"2019-07-10T10:47:58.000-04:00\", \"date_of_expiration\": null, \"money_release_date\": \"2019-07-24T10:47:58.000-04:00\", \"operation_type\": \"regular_payment\", \"issuer_id\": \"25\", \"payment_method_id\": \"visa\", \"payment_type_id\": \"credit_card\", \"status\": \"approved\"}",
+       headers: [
+         {"Content-Type", "application/json"},
+         {"Access-Control-Allow-Origin", "*"},
+         {"Access-Control-Allow-Methods", "PUT,OPTIONS,POST,GET"},
+         {"Date", "Mon, 25 Dec 2017 14:17:56 GMT"}
+       ],
+       request_url: "#{@base_url}/v1/payments",
+       status_code: 200
+     }}
+  end
+
+  # capture mock response
+
+  def successful_capture_response do
+    {:ok,
+     %HTTPoison.Response{
+       body:
+         "{\"id\": 20359978, \"date_created\": \"2019-07-10T10:47:58.000-04:00\", \"date_approved\": \"2019-07-10T10:47:58.000-04:00\", \"date_last_updated\": \"2019-07-10T10:47:58.000-04:00\", \"date_of_expiration\": null, \"money_release_date\": \"2019-07-24T10:47:58.000-04:00\", \"operation_type\": \"regular_payment\", \"issuer_id\": \"25\", \"payment_method_id\": \"visa\", \"payment_type_id\": \"credit_card\", \"status\": \"approved\"}",
+       headers: [
+         {"Content-Type", "application/json"},
+         {"Access-Control-Allow-Origin", "*"},
+         {"Access-Control-Allow-Methods", "PUT,OPTIONS,POST,GET"},
+         {"Date", "Mon, 25 Dec 2017 14:17:56 GMT"}
+       ],
+       request_url: "#{@base_url}/v1/payments",
+       status_code: 200
+     }}
+  end
+
+  def bad_id_capture do
+    {:error,
+     %HTTPoison.Error{
+       reason: "Bad ID for Capture",
+       id: 1_234_567
+     }}
+  end
+
+  # refund mock response
+  def successful_refund_response do
+    {:ok,
+     %HTTPoison.Response{
+       body:
+         "{\"id\": 20359978, \"payment_id\":24686811, \"unique_sequence_number\":null,\"refund_mode\":\"standard\",\"status\":\"approved\", \"source\":{\"id\":\"543713181\",\"name\":\"Developer Testing\",\"type\":\"collector\"} }",
+       headers: [
+         {"Date", "Mon, 25 Dec 2017 14:17:56 GMT"},
+         {"Content-Type", "application/json"},
+         {"Transfer-Encoding", "chunked"},
+         {"Connection", "keep-alive"},
+         {"Cache-Control", "max-age=0"},
+         {"ETag", "e2894bf98b818a4f49a3bd1065a3d9b8"},
+         {"Vary", "Accept,Accept-Encoding,Accept-Encoding"},
+         {"X-Content-Type-Options", "nosniff"},
+         {"X-Request-Id", "f6d28d4c-ce70-4cf4-ac82-5733f826eef6"},
+         {"X-XSS-Protection", "1; mode=block"},
+         {"Strict-Transport-Security", "max-age=16070400; includeSubDomains; preload"},
+         {"Access-Control-Allow-Origin", "*"},
+         {"Access-Control-Allow-Headers", "Content-Type"},
+         {"Access-Control-Allow-Methods", "PUT,OPTIONS,POST,GET"},
+         {"Access-Control-Max-Age", "86400"},
+         {"Timing-Allow-Origin", "*"}
+       ],
+       request_url: "#{@base_url}/v1/payments",
+       status_code: 200
+     }}
+  end
+
+  def bad_card_refund do
+    {:error,
+     %HTTPoison.Error{
+       reason: "Bad Card for refund",
+       id: 1_234_567
+     }}
+  end
+
+  def debit_less_than_refund do
+    {:error,
+     %HTTPoison.Error{
+       reason: "Debit less than refund",
+       id: 1_234_567
+     }}
+  end
+
+  # void mock response
+  def successful_void do
+    {:ok,
+     %HTTPoison.Response{
+       body:
+         "{\"id\": 20359978, \"date_created\": \"2019-07-10T10:47:58.000-04:00\", \"date_approved\": \"2019-07-10T10:47:58.000-04:00\", \"date_last_updated\": \"2019-07-10T10:47:58.000-04:00\", \"date_of_expiration\": null, \"money_release_date\": \"2019-07-24T10:47:58.000-04:00\", \"operation_type\": \"regular_payment\", \"issuer_id\": \"25\", \"payment_method_id\": \"visa\", \"payment_type_id\": \"credit_card\", \"status\": \"approved\"}",
+       headers: [
+         {"Content-Type", "application/json"},
+         {"Access-Control-Allow-Origin", "*"},
+         {"Access-Control-Allow-Methods", "PUT,OPTIONS,POST,GET"},
+         {"Date", "Mon, 25 Dec 2017 14:17:56 GMT"}
+       ],
+       request_url: "#{@base_url}/v1/payments",
+       status_code: 200
+     }}
+  end
+
+  def void_non_existent_id do
+    {:error,
+     %HTTPoison.Error{
+       reason: "Transaction ID does not exist for Void",
+       id: 1_234_567
+     }}
+  end
+
+  def customer_payment_profile_success_response do
+    {:ok,
+     %HTTPoison.Response{
+       body:
+         "{\"id\": 20359978, \"date_created\": \"2019-07-10T10:47:58.000-04:00\", \"date_approved\": \"2019-07-10T10:47:58.000-04:00\", \"date_last_updated\": \"2019-07-10T10:47:58.000-04:00\", \"date_of_expiration\": null, \"money_release_date\": \"2019-07-24T10:47:58.000-04:00\", \"operation_type\": \"regular_payment\", \"issuer_id\": \"25\", \"payment_method_id\": \"visa\", \"payment_type_id\": \"credit_card\", \"status\": \"approved\"}",
+       headers: [
+         {"Content-Type", "application/json"},
+         {"Access-Control-Allow-Origin", "*"},
+         {"Access-Control-Allow-Methods", "PUT,OPTIONS,POST,GET"},
+         {"Date", "Mon, 25 Dec 2017 14:17:56 GMT"}
+       ],
+       request_url: "#{@base_url}/v1/payments",
+       status_code: 200
+     }}
+  end
+
+  def netwok_error_non_existent_domain do
+    {:error, %HTTPoison.Error{id: nil, reason: :nxdomain}}
+  end
+end