diff --git a/app/models/webhook_request.rb b/app/models/webhook_request.rb
index c475155..7609b5a 100644
--- a/app/models/webhook_request.rb
+++ b/app/models/webhook_request.rb
@@ -28,8 +28,6 @@ class WebhookRequest < ApplicationRecord
   include HasUUID
   include HasLocking
 
-  RETRIES = { 1 => 2.minutes, 2 => 3.minutes, 3 => 6.minutes, 4 => 10.minutes, 5 => 15.minutes }.freeze
-
   belongs_to :server
   belongs_to :webhook, optional: true
 
@@ -38,48 +36,6 @@ class WebhookRequest < ApplicationRecord
 
   serialize :payload, Hash
 
-  def deliver
-    payload = { event: event, timestamp: created_at.to_f, payload: self.payload, uuid: uuid }.to_json
-    Postal.logger.tagged(event: event, url: url) do
-      Postal.logger.info "Sending webhook request"
-      result = Postal::HTTP.post(url, sign: true, json: payload, timeout: 5)
-      self.attempts += 1
-      self.retry_after = RETRIES[self.attempts]&.from_now
-      server.message_db.webhooks.record(
-        event: event,
-        url: url,
-        webhook_id: webhook_id,
-        attempt: self.attempts,
-        timestamp: Time.now.to_f,
-        payload: self.payload.to_json,
-        uuid: uuid,
-        status_code: result[:code],
-        body: result[:body],
-        will_retry: (retry_after ? 0 : 1)
-      )
-
-      if result[:code] >= 200 && result[:code] < 300
-        Postal.logger.info "Received #{result[:code]} status code. That's OK."
-        destroy!
-        webhook&.update_column(:last_used_at, Time.now)
-        true
-      else
-        Postal.logger.error "Received #{result[:code]} status code. That's not OK."
-        self.error = "Couldn't send to URL. Code received was #{result[:code]}"
-        if retry_after
-          Postal.logger.info "Will retry #{retry_after} (this was attempt #{self.attempts})"
-          self.locked_by = nil
-          self.locked_at = nil
-          save!
-        else
-          Postal.logger.info "Have tried #{self.attempts} times. Giving up."
-          destroy!
-        end
-        false
-      end
-    end
-  end
-
   class << self
 
     def trigger(server, event, payload = {})
diff --git a/app/services/webhook_delivery_service.rb b/app/services/webhook_delivery_service.rb
index 617054e..4aeb50c 100644
--- a/app/services/webhook_delivery_service.rb
+++ b/app/services/webhook_delivery_service.rb
@@ -2,18 +2,96 @@
 
 class WebhookDeliveryService
 
-  def initialize(webhook_delivery:)
-    @webhook_delivery = webhook_delivery
+  RETRIES = { 1 => 2.minutes, 2 => 3.minutes, 3 => 6.minutes, 4 => 10.minutes, 5 => 15.minutes }.freeze
+
+  def initialize(webhook_request:)
+    @webhook_request = webhook_request
   end
 
-  # TODO: move the logic from WebhookDelivery#deliver in to this service.
-  #
   def call
-    if @webhook_delivery.deliver
-      log "Succesfully delivered"
-    else
-      log "Delivery failed"
+    logger.tagged(webhook: @webhook_request.webhook_id, webhook_request: @webhook_request.id) do
+      generate_payload
+      send_request
+      record_attempt
+      appreciate_http_result
+      update_webhook_request
     end
   end
 
+  def success?
+    @success == true
+  end
+
+  private
+
+  def generate_payload
+    @payload = {
+      event: @webhook_request.event,
+      timestamp: @webhook_request.created_at.to_f,
+      payload: @webhook_request.payload,
+      uuid: @webhook_request.uuid
+    }.to_json
+  end
+
+  def send_request
+    @http_result = Postal::HTTP.post(@webhook_request.url,
+                                     sign: true,
+                                     json: @payload,
+                                     timeout: 5)
+
+    @success = (@http_result[:code] >= 200 && @http_result[:code] < 300)
+  end
+
+  def record_attempt
+    @webhook_request.attempts += 1
+
+    if success?
+      @webhook_request.retry_after = nil
+    else
+      @webhook_request.retry_after = RETRIES[@webhook_request.attempts]&.from_now
+    end
+
+    @attempt = @webhook_request.server.message_db.webhooks.record(
+      event: @webhook_request.event,
+      url: @webhook_request.url,
+      webhook_id: @webhook_request.webhook_id,
+      attempt: @webhook_request.attempts,
+      timestamp: Time.now.to_f,
+      payload: @webhook_request.payload.to_json,
+      uuid: @webhook_request.uuid,
+      status_code: @http_result[:code],
+      body: @http_result[:body],
+      will_retry: @webhook_request.retry_after.present?
+    )
+  end
+
+  def appreciate_http_result
+    if success?
+      logger.info "Received #{@http_result[:code]} status code. That's OK."
+      @webhook_request.destroy!
+      @webhook_request.webhook&.update_column(:last_used_at, Time.current)
+      return
+    end
+
+    logger.error "Received #{@http_result[:code]} status code. That's not OK."
+    @webhook_request.error = "Couldn't send to URL. Code received was #{@http_result[:code]}"
+  end
+
+  def update_webhook_request
+    if @webhook_request.retry_after
+      logger.info "Will retry #{@webhook_request.retry_after} (this was attempt #{@webhook_request.attempts})"
+      @webhook_request.locked_by = nil
+      @webhook_request.locked_at = nil
+      @webhook_request.save!
+      return
+    end
+
+    logger.info "Have tried #{@webhook_request.attempts} times. Giving up."
+    @webhook_request.destroy!
+  end
+
+  def logger
+    Postal.logger
+  end
+
 end
diff --git a/lib/postal/message_db/database.rb b/lib/postal/message_db/database.rb
index 061e1e4..c5c3e38 100644
--- a/lib/postal/message_db/database.rb
+++ b/lib/postal/message_db/database.rb
@@ -325,7 +325,7 @@ module Postal
         result = connection.query(query, cast_booleans: true)
         time = Time.now.to_f - start_time
         logger.debug "  \e[4;34mMessageDB Query (#{time.round(2)}s) \e[0m  \e[33m#{query}\e[0m"
-        if time.positive? && query =~ /\A(SELECT|UPDATE|DELETE) /
+        if time > 0.05 && query =~ /\A(SELECT|UPDATE|DELETE) /
           id = Nifty::Utils::RandomString.generate(length: 6).upcase
           explain_result = ResultForExplainPrinter.new(connection.query("EXPLAIN #{query}"))
           logger.info "  [#{id}] EXPLAIN #{query}"
diff --git a/lib/postal/message_db/webhooks.rb b/lib/postal/message_db/webhooks.rb
index cfe4bcd..97bbad5 100644
--- a/lib/postal/message_db/webhooks.rb
+++ b/lib/postal/message_db/webhooks.rb
@@ -12,7 +12,7 @@ module Postal
         @database.insert(:webhook_requests, attributes)
       end
 
-      def list(page)
+      def list(page = 1)
         result = @database.select_with_pagination(:webhook_requests, page, order: :timestamp, direction: "desc")
         result[:records] = result[:records].map { |i| Request.new(i) }
         result
diff --git a/lib/worker/jobs/process_webhook_requests_job.rb b/lib/worker/jobs/process_webhook_requests_job.rb
index c33de5f..53751a1 100644
--- a/lib/worker/jobs/process_webhook_requests_job.rb
+++ b/lib/worker/jobs/process_webhook_requests_job.rb
@@ -39,7 +39,8 @@ module Worker
       def process_requests
         @requests_to_process.each do |request|
           work_completed!
-          request.deliver
+
+          WebhookDeliveryService.new(webhook_request: request).call
         end
       end
 
diff --git a/spec/app/services/webhook_delivery_service_spec.rb b/spec/app/services/webhook_delivery_service_spec.rb
new file mode 100644
index 0000000..3527e71
--- /dev/null
+++ b/spec/app/services/webhook_delivery_service_spec.rb
@@ -0,0 +1,119 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe WebhookDeliveryService do
+  let(:server) { GLOBAL_SERVER }
+  let(:webhook) { create(:webhook, server: server) }
+  let(:webhook_request) { create(:webhook_request, :locked, webhook: webhook) }
+
+  subject(:service) { described_class.new(webhook_request: webhook_request) }
+
+  let(:response_status) { 200 }
+  let(:response_body) { "OK" }
+
+  before do
+    stub_request(:post, webhook.url).to_return(status: response_status, body: response_body)
+  end
+
+  after do
+    server.message_db.provisioner.clean
+  end
+
+  describe "#call" do
+    it "sends a request to the webhook's url" do
+      service.call
+      expect(WebMock).to have_requested(:post, webhook.url).with({
+        body: {
+          event: webhook_request.event,
+          timestamp: webhook_request.created_at.to_f,
+          payload: webhook_request.payload,
+          uuid: webhook_request.uuid
+        }.to_json,
+        headers: {
+          "Content-Type" => "application/json",
+          "X-Postal-Signature" => /\A[a-z0-9\/+]+=*\z/i
+        }
+      })
+    end
+
+    context "when the endpoint returns a 200 OK" do
+      it "creates a webhook request for the server" do
+        service.call
+        expect(server.message_db.webhooks.list(1)[:total]).to eq(1)
+        webhook_request = server.message_db.webhooks.list(1)[:records].first
+        expect(webhook_request).to have_attributes(
+          event: webhook_request.event,
+          url: webhook_request.url,
+          status_code: 200,
+          body: "OK",
+          uuid: webhook_request.uuid,
+          will_retry?: false,
+          payload: webhook_request.payload,
+          attempt: 1,
+          timestamp: webhook_request.timestamp
+        )
+      end
+
+      it "deletes the webhook request" do
+        service.call
+        expect { webhook_request.reload }.to raise_error(ActiveRecord::RecordNotFound)
+      end
+
+      it "updates the last used at time on the webhook" do
+        service.call
+        expect(webhook.reload.last_used_at).to be_within(1.second).of(Time.current)
+      end
+    end
+
+    context "when the request returns a 500 Internal Server Error for the first time" do
+      let(:response_status) { 500 }
+      let(:response_body) { "internal server error!" }
+
+      it "unlocks the webhook request if locked" do
+        expect { service.call }.to change { webhook_request.reload.locked? }.from(true).to(false)
+      end
+
+      it "updates the retry time and attempt counter" do
+        service.call
+        expect(webhook_request.reload.attempts).to eq(1)
+        expect(webhook_request.retry_after).to be_within(1.second).of(2.minutes.from_now)
+      end
+    end
+
+    context "when the request returns a 500 Internal Server Error for the second time" do
+      let(:webhook_request) { create(:webhook_request, :locked, webhook: webhook, attempts: 1) }
+      let(:response_status) { 500 }
+      let(:response_body) { "internal server error!" }
+
+      it "updates the retry time and attempt counter" do
+        service.call
+        expect(webhook_request.reload.attempts).to eq(2)
+        expect(webhook_request.retry_after).to be_within(1.second).of(3.minutes.from_now)
+      end
+    end
+
+    context "when the request returns a 500 Internal Server Error for the sixth time" do
+      let(:webhook_request) { create(:webhook_request, :locked, webhook: webhook, attempts: 5) }
+      let(:response_status) { 500 }
+      let(:response_body) { "internal server error!" }
+
+      it "creates a webhook request for the server" do
+        service.call
+        expect(server.message_db.webhooks.list(1)[:total]).to eq(1)
+        webhook_request = server.message_db.webhooks.list(1)[:records].first
+        expect(webhook_request).to have_attributes(
+          status_code: 500,
+          body: "internal server error!",
+          will_retry?: false,
+          attempt: 6
+        )
+      end
+
+      it "deletes the webhook request" do
+        service.call
+        expect { webhook_request.reload }.to raise_error(ActiveRecord::RecordNotFound)
+      end
+    end
+  end
+end