diff --git a/app/controllers/tournaments_controller.rb b/app/controllers/tournaments_controller.rb
index 3625ef7..bc29529 100644
--- a/app/controllers/tournaments_controller.rb
+++ b/app/controllers/tournaments_controller.rb
@@ -171,14 +171,18 @@ class TournamentsController < ApplicationController
   def timer_params
     {
       timestamp: params[:timestamp],
-      timer_mode: params[:timer_mode]
+      timer_mode: params[:timer_mode],
+      timer_reason: params[:timer_reason],
+      timer_reason_text: params[:timer_reason_text]
     }
   end
 
   def serialize_timer_state(tournament)
     {
       timestamp: tournament.timestamp&.iso8601,
-      timer_mode: tournament.timer_mode
+      timer_mode: tournament.timer_mode,
+      timer_reason: tournament.timer_reason,
+      timer_reason_text: tournament.timer_reason_text
     }
   end
 
@@ -333,40 +337,41 @@ class TournamentsController < ApplicationController
     timestamp = params[:timestamp]
     timestamp_seconds = params[:timestamp_seconds]
     timer_mode = params[:timer_mode]
+    normalize_timer_reason_params
+    timer_reason = params[:timer_reason]
+    timer_reason_text = params[:timer_reason_text]
     clear_timer = ActiveModel::Type::Boolean.new.cast(params[:clear_timer])
 
     if clear_timer
-      if timestamp.present? || timestamp_seconds.present? || timer_mode.present?
-        return render json: { error: 'clear_timer cannot be combined with timestamp values or timer_mode' },
-                      status: :unprocessable_entity
-      end
-
-      params[:timestamp] = nil
-      params[:timer_mode] = nil
-      return
+      return validate_clear_timer_params(timestamp, timestamp_seconds, timer_mode, timer_reason, timer_reason_text)
     end
 
-    if timer_mode.present? && !%w[countdown countup].include?(timer_mode)
-      return render json: { error: 'Invalid timer_mode' }, status: :unprocessable_entity
+    if timer_mode.present? && !Tournament::TIMER_MODES.include?(timer_mode)
+      return render_timer_validation_error('Invalid timer_mode')
     end
 
+    timer_reason_error = validate_timer_reason_params(timer_reason, timer_reason_text)
+    return render_timer_validation_error(timer_reason_error) if timer_reason_error
+
     # throw error if both timestamp and timestamp_seconds are present
     if timestamp.present? && timestamp_seconds.present?
-      return render json: { error: 'Only one of timestamp or timestamp_seconds is allowed' }, status: :unprocessable_entity
+      return render_timer_validation_error('Only one of timestamp or timestamp_seconds is allowed')
     end
 
     if timer_mode == 'countup' && timestamp_seconds.present?
-      return render json: { error: 'timestamp_seconds is only allowed for countdown mode' }, status: :unprocessable_entity
+      return render_timer_validation_error('timestamp_seconds is only allowed for countdown mode')
     end
 
     if timestamp_seconds.present?
       begin
         timestamp_seconds = Integer(timestamp_seconds)
       rescue ArgumentError
-        return render json: { error: 'Invalid seconds format' }, status: :unprocessable_entity
+        return render_timer_validation_error('Invalid seconds format')
       end
 
-      return render json: { error: 'Timestamp must be in the future for countdown mode' }, status: :unprocessable_entity if timestamp_seconds <= 0
+      if timestamp_seconds <= 0
+        return render_timer_validation_error('Timestamp must be in the future for countdown mode')
+      end
 
       parsed_time = Time.zone.now + timestamp_seconds
       params[:timestamp] = parsed_time
@@ -375,24 +380,63 @@ class TournamentsController < ApplicationController
       begin
         parsed_time = Time.zone.parse(timestamp)
         if parsed_time.nil?
-          return render json: { error: 'Invalid timestamp format' }, status: :unprocessable_entity
+          return render_timer_validation_error('Invalid timestamp format')
         elsif timer_mode != 'countup' && !parsed_time.future?
-          return render json: { error: 'Timestamp must be in the future for countdown mode' }, status: :unprocessable_entity
+          return render_timer_validation_error('Timestamp must be in the future for countdown mode')
         end
 
         params[:timestamp] = parsed_time
         params[:timer_mode] = timer_mode.presence || 'countdown'
       rescue ArgumentError
-        return render json: { error: 'Invalid timestamp format' }, status: :unprocessable_entity
+        return render_timer_validation_error('Invalid timestamp format')
       end
     elsif timer_mode == 'countup'
       params[:timestamp] = Time.zone.now
     elsif timer_mode.present?
-      return render json: { error: 'timer_mode requires timestamp, timestamp_seconds, or clear_timer' },
-                    status: :unprocessable_entity
+      return render_timer_validation_error('timer_mode requires timestamp, timestamp_seconds, or clear_timer')
     else
-      return render json: { error: 'timestamp, timestamp_seconds, or clear_timer is required' },
-                    status: :unprocessable_entity
+      return render_timer_validation_error('timestamp, timestamp_seconds, or clear_timer is required')
     end
   end
+
+  def normalize_timer_reason_params
+    params[:timer_reason] = params[:timer_reason].presence
+    params[:timer_reason_text] = timer_reason_text_param
+  end
+
+  def timer_reason_text_param
+    return nil unless params.key?(:timer_reason_text)
+
+    params[:timer_reason_text].to_s.strip.presence
+  end
+
+  def validate_clear_timer_params(timestamp, timestamp_seconds, timer_mode, timer_reason, timer_reason_text)
+    if timestamp.present? || timestamp_seconds.present? || timer_mode.present? ||
+       timer_reason.present? || timer_reason_text.present?
+      return render_timer_validation_error('clear_timer cannot be combined with timer values or timer reason')
+    end
+
+    params[:timestamp] = nil
+    params[:timer_mode] = nil
+    params[:timer_reason] = nil
+    params[:timer_reason_text] = nil
+  end
+
+  def validate_timer_reason_params(timer_reason, timer_reason_text)
+    return if timer_reason.blank? && timer_reason_text.blank?
+    return 'timer_reason_text is only allowed when timer_reason is custom' if timer_reason.blank?
+    return 'Invalid timer_reason' unless Tournament::TIMER_REASONS.include?(timer_reason)
+
+    if timer_reason == 'custom' && timer_reason_text.blank?
+      return 'timer_reason_text is required for custom timer_reason'
+    end
+
+    if timer_reason != 'custom' && timer_reason_text.present?
+      'timer_reason_text is only allowed when timer_reason is custom'
+    end
+  end
+
+  def render_timer_validation_error(message)
+    render json: { error: message }, status: :unprocessable_entity
+  end
 end
diff --git a/app/models/tournament.rb b/app/models/tournament.rb
index 3debf27..9decf6c 100644
--- a/app/models/tournament.rb
+++ b/app/models/tournament.rb
@@ -3,6 +3,9 @@
 require 'securerandom'
 
 class Tournament < ApplicationRecord
+  TIMER_MODES = %w[countdown countup].freeze
+  TIMER_REASONS = %w[tournament_start playoff_start match_end custom].freeze
+
   belongs_to :user
   has_many :teams, dependent: :destroy
   has_many :stages, dependent: :destroy
@@ -11,16 +14,19 @@ class Tournament < ApplicationRecord
 
   validates :name, presence: true
   validates :code, presence: true, uniqueness: true
-  validates :timer_mode, inclusion: { in: %w[countdown countup] }, allow_nil: true
+  validates :timer_mode, inclusion: { in: TIMER_MODES }, allow_nil: true
+  validates :timer_reason, inclusion: { in: TIMER_REASONS }, allow_nil: true
   validates :sync_target_url, format: URI::DEFAULT_PARSER.make_regexp(%w[http https]), allow_blank: true
   validate :sync_configuration_is_complete
 
   validate :playoff_teams_amount_is_positive_power_of_two
+  validate :timer_reason_text_matches_reason
 
   alias_attribute :owner, :user
 
   after_initialize :generate_code
   after_create_commit :ensure_default_beamer!
+  before_validation :normalize_timer_reason
   before_validation :clear_follower_sync_token_when_disabling_read_only_mode
   after_commit :broadcast_timer_state_change, if: :saved_change_to_timer_state?
 
@@ -100,8 +106,24 @@ class Tournament < ApplicationRecord
     self.sync_auth_token = nil
   end
 
+  def normalize_timer_reason
+    self.timer_reason = timer_reason.presence
+    self.timer_reason_text = timer_reason_text&.strip&.presence
+  end
+
+  def timer_reason_text_matches_reason
+    if timer_reason == 'custom'
+      errors.add(:timer_reason_text, "can't be blank") if timer_reason_text.blank?
+    elsif timer_reason_text.present?
+      errors.add(:timer_reason_text, 'is only allowed when timer_reason is custom')
+    end
+  end
+
   def saved_change_to_timer_state?
-    saved_change_to_timestamp? || saved_change_to_timer_mode?
+    saved_change_to_timestamp? ||
+      saved_change_to_timer_mode? ||
+      saved_change_to_timer_reason? ||
+      saved_change_to_timer_reason_text?
   end
 
   def broadcast_timer_state_change
diff --git a/app/serializers/tournament_serializer.rb b/app/serializers/tournament_serializer.rb
index 46009a1..2691690 100644
--- a/app/serializers/tournament_serializer.rb
+++ b/app/serializers/tournament_serializer.rb
@@ -16,6 +16,8 @@ class TournamentSerializer < SimpleTournamentSerializer
   end
 
   attribute :timer_mode
+  attribute :timer_reason
+  attribute :timer_reason_text
 
   attribute :sync_last_pushed_at, if: :sync_metadata_visible? do
     object.sync_last_pushed_at&.iso8601
diff --git a/app/services/tournament_snapshot_builder.rb b/app/services/tournament_snapshot_builder.rb
index 8ca4a26..0975a78 100644
--- a/app/services/tournament_snapshot_builder.rb
+++ b/app/services/tournament_snapshot_builder.rb
@@ -24,6 +24,8 @@ class TournamentSnapshotBuilder
     payload = tournament.attributes.symbolize_keys.slice(*ROOT_ATTRIBUTES)
     payload[:timestamp] = tournament.timestamp&.iso8601
     payload[:timer_mode] = tournament.timer_mode
+    payload[:timer_reason] = tournament.timer_reason
+    payload[:timer_reason_text] = tournament.timer_reason_text
     payload[:sync_generated_at] = Time.current.iso8601(6)
     payload[:teams] = teams_payload
     payload[:beamers] = beamers_payload
diff --git a/app/services/tournament_snapshot_importer.rb b/app/services/tournament_snapshot_importer.rb
index af298c2..c2868da 100644
--- a/app/services/tournament_snapshot_importer.rb
+++ b/app/services/tournament_snapshot_importer.rb
@@ -69,6 +69,8 @@ class TournamentSnapshotImporter
     root_attrs[:code] = tournament.code if code_taken_by_another_tournament?(root_attrs[:code])
     root_attrs[:timestamp] = parse_time(snapshot[:timestamp])
     root_attrs[:timer_mode] = snapshot[:timer_mode]
+    root_attrs[:timer_reason] = snapshot[:timer_reason]
+    root_attrs[:timer_reason_text] = snapshot[:timer_reason_text]
     root_attrs[:sync_source_tournament_id] = snapshot[:id]
     root_attrs[:sync_last_imported_snapshot_at] = snapshot_generated_at
     tournament.update!(root_attrs)
diff --git a/app/services/tournament_sync_schema.rb b/app/services/tournament_sync_schema.rb
index 64b4d33..d698bf5 100644
--- a/app/services/tournament_sync_schema.rb
+++ b/app/services/tournament_sync_schema.rb
@@ -14,6 +14,8 @@ class TournamentSyncSchema
         intermediate_round_participants_amount
         timestamp
         timer_mode
+        timer_reason
+        timer_reason_text
       ].freeze,
       ignored: %w[
         user_id
diff --git a/app/services/tournament_timer_broadcast_payload.rb b/app/services/tournament_timer_broadcast_payload.rb
index 9b790de..80bdf5c 100644
--- a/app/services/tournament_timer_broadcast_payload.rb
+++ b/app/services/tournament_timer_broadcast_payload.rb
@@ -7,7 +7,9 @@ class TournamentTimerBroadcastPayload
         type: 'timer.updated',
         tournament_id: tournament.id,
         timestamp: tournament.timestamp&.iso8601,
-        timer_mode: tournament.timer_mode
+        timer_mode: tournament.timer_mode,
+        timer_reason: tournament.timer_reason,
+        timer_reason_text: tournament.timer_reason_text
       }
     end
   end
diff --git a/db/migrate/20260428120000_add_timer_reason_to_tournaments.rb b/db/migrate/20260428120000_add_timer_reason_to_tournaments.rb
new file mode 100644
index 0000000..54cb911
--- /dev/null
+++ b/db/migrate/20260428120000_add_timer_reason_to_tournaments.rb
@@ -0,0 +1,6 @@
+class AddTimerReasonToTournaments < ActiveRecord::Migration[7.0]
+  def change
+    add_column :tournaments, :timer_reason, :string
+    add_column :tournaments, :timer_reason_text, :text
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 002741a..9ebcac7 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2026_04_26_121000) do
+ActiveRecord::Schema[7.0].define(version: 2026_04_28_120000) do
   create_table "beamers", force: :cascade do |t|
     t.string "name", null: false
     t.string "display_state", default: "during_game", null: false
@@ -167,6 +167,8 @@ ActiveRecord::Schema[7.0].define(version: 2026_04_26_121000) do
     t.string "sync_last_push_error"
     t.datetime "sync_last_imported_snapshot_at"
     t.string "timer_mode"
+    t.string "timer_reason"
+    t.text "timer_reason_text"
     t.index ["code"], name: "index_tournaments_on_code", unique: true
     t.index ["user_id"], name: "index_tournaments_on_user_id"
   end
diff --git a/doc/timer_api.md b/doc/timer_api.md
index dcb1169..f1d0622 100644
--- a/doc/timer_api.md
+++ b/doc/timer_api.md
@@ -15,6 +15,8 @@ Frontend should treat timer state as:
 - no timer: `timestamp = null`, `timer_mode = null`
 - countdown: `timer_mode = "countdown"`
 - countup: `timer_mode = "countup"`
+- optional reason: `timer_reason` may be `tournament_start`, `playoff_start`, `match_end`, or `custom`
+- custom reason: `timer_reason = "custom"` and `timer_reason_text` contains the display text
 
 ## Read Flow
 
@@ -31,7 +33,9 @@ Response shape:
 ```json
 {
   "timestamp": "2026-04-24T10:15:00Z",
-  "timer_mode": "countdown"
+  "timer_mode": "countdown",
+  "timer_reason": "tournament_start",
+  "timer_reason_text": null
 }
 ```
 
@@ -40,6 +44,13 @@ Possible values:
 - `timer_mode = "countdown"`
 - `timer_mode = "countup"`
 - `timer_mode = null`
+- `timer_reason = "tournament_start"`
+- `timer_reason = "playoff_start"`
+- `timer_reason = "match_end"`
+- `timer_reason = "custom"`
+- `timer_reason = null`
+
+`timer_reason_text` is only used when `timer_reason = "custom"`.
 
 ## Meaning Of `timestamp`
 
@@ -103,7 +114,8 @@ Request:
 
 ```json
 {
-  "timestamp_seconds": 120
+  "timestamp_seconds": 120,
+  "timer_reason": "tournament_start"
 }
 ```
 
@@ -120,7 +132,8 @@ Request:
 
 ```json
 {
-  "timestamp": "2026-04-24T10:15:00Z"
+  "timestamp": "2026-04-24T10:15:00Z",
+  "timer_reason": "playoff_start"
 }
 ```
 
@@ -129,7 +142,9 @@ Optional explicit mode:
 ```json
 {
   "timestamp": "2026-04-24T10:15:00Z",
-  "timer_mode": "countdown"
+  "timer_mode": "countdown",
+  "timer_reason": "custom",
+  "timer_reason_text": "Opening ceremony ran long"
 }
 ```
 
@@ -139,7 +154,8 @@ Request:
 
 ```json
 {
-  "timer_mode": "countup"
+  "timer_mode": "countup",
+  "timer_reason": "match_end"
 }
 ```
 
@@ -157,7 +173,9 @@ Backend also accepts explicit timestamp with countup mode:
 ```json
 {
   "timestamp": "2026-04-24T10:00:00Z",
-  "timer_mode": "countup"
+  "timer_mode": "countup",
+  "timer_reason": "custom",
+  "timer_reason_text": "Manual overtime"
 }
 ```
 
@@ -179,10 +197,12 @@ Request:
 
 Behavior:
 
-- backend clears both fields
+- backend clears all timer fields
 - response returns:
   - `timestamp = null`
   - `timer_mode = null`
+  - `timer_reason = null`
+  - `timer_reason_text = null`
 
 ## Validation Rules
 
@@ -194,6 +214,9 @@ Backend rejects:
 - `timestamp_seconds` together with `timer_mode = "countup"`
 - `timer_mode` by itself unless it is `countup`
 - `clear_timer` mixed with timer values
+- invalid `timer_reason`
+- `timer_reason = "custom"` without `timer_reason_text`
+- `timer_reason_text` with any non-custom `timer_reason`
 
 Countdown timestamps must be future timestamps.
 Countup timestamps may be current or past timestamps.
@@ -223,7 +246,9 @@ Payload:
   "type": "timer.updated",
   "tournament_id": 123,
   "timestamp": "2026-04-24T10:15:00Z",
-  "timer_mode": "countdown"
+  "timer_mode": "countdown",
+  "timer_reason": "tournament_start",
+  "timer_reason_text": null
 }
 ```
 
@@ -243,7 +268,7 @@ Frontend rule:
 Recommended flow:
 
 1. Load tournament via `GET /tournaments/:id`
-2. Read `timer_mode` and `timestamp`
+2. Read `timer_mode`, `timestamp`, `timer_reason`, and `timer_reason_text`
 3. Open ActionCable subscription for same tournament id
 4. Replace local timer state whenever `timer.updated` arrives
 5. Derive displayed time from `Date.now()` plus stored backend timestamp
@@ -252,9 +277,11 @@ Recommended client state:
 
 ```ts
 type TimerState =
-  | { mode: null; timestampIso: null }
-  | { mode: "countdown"; timestampIso: string }
-  | { mode: "countup"; timestampIso: string };
+  | { mode: null; timestampIso: null; reason: null; reasonText: null }
+  | { mode: "countdown"; timestampIso: string; reason: TimerReason | null; reasonText: string | null }
+  | { mode: "countup"; timestampIso: string; reason: TimerReason | null; reasonText: string | null };
+
+type TimerReason = "tournament_start" | "playoff_start" | "match_end" | "custom";
 ```
 
 Suggested derivation logic:
@@ -283,7 +310,7 @@ Recommended rendering:
 
 Recommended local ticking:
 
-- keep backend state as timestamp + mode
+- keep backend state as timestamp + mode + reason
 - update rendered value with local interval
 - do not poll backend every second
 
@@ -300,7 +327,7 @@ Timer state is included in tournament sync snapshots.
 That means:
 
 - leader timer changes propagate to follower
-- follower tournament exposes same `timestamp` / `timer_mode`
+- follower tournament exposes same `timestamp` / `timer_mode` / `timer_reason` / `timer_reason_text`
 - follower websocket subscribers receive `timer.updated`
 - follower still rejects timer writes while read only
 
@@ -321,5 +348,5 @@ Implemented coverage:
 
 Current note:
 
-- single-backend HTTP E2E timer specs pass
+- single-backend and local dual-server HTTP E2E timer specs pass
 - follower blackbox task still has existing Docker/network issue in follow setup, so production-style follow stack verification is not green yet
diff --git a/doc/tournament_live_updates.md b/doc/tournament_live_updates.md
index 9d8f9f4..fb87d47 100644
--- a/doc/tournament_live_updates.md
+++ b/doc/tournament_live_updates.md
@@ -70,6 +70,8 @@ Payload:
     "intermediate_round_participants_amount": 0,
     "timestamp": null,
     "timer_mode": null,
+    "timer_reason": null,
+    "timer_reason_text": null,
     "owner_username": "owner",
     "stages": [],
     "teams": [],
diff --git a/e2e/lib/scenario_runner.rb b/e2e/lib/scenario_runner.rb
index eb67787..664db82 100644
--- a/e2e/lib/scenario_runner.rb
+++ b/e2e/lib/scenario_runner.rb
@@ -30,9 +30,12 @@ module TurniereE2E
 
       timer_response = patch!(
         "/tournaments/#{tournament.fetch(:id)}/timer",
-        body: { timestamp_seconds: 600 }
+        body: { timestamp_seconds: 600, timer_reason: 'tournament_start' }
       )
-      checkpoints[:timer_set] = { timestamp: timer_response.fetch(:timestamp) }
+      checkpoints[:timer_set] = {
+        timestamp: timer_response.fetch(:timestamp),
+        timer_reason: timer_response.fetch(:timer_reason)
+      }
       return result(session: session, tournament: tournament, checkpoints: checkpoints, stop_at: stop_at) if stop_at == :timer_set
 
       upcoming_matches = get!(
diff --git a/spec/controllers/tournaments_controller_spec.rb b/spec/controllers/tournaments_controller_spec.rb
index 9a9cb9a..2f95deb 100644
--- a/spec/controllers/tournaments_controller_spec.rb
+++ b/spec/controllers/tournaments_controller_spec.rb
@@ -105,7 +105,7 @@ RSpec.describe TournamentsController, type: :controller do
       expected_keys = %i[
         id name code public description playoff_teams_amount
         instant_finalists_amount intermediate_round_participants_amount
-        timestamp timer_mode owner_username stages teams team_action_lists
+        timestamp timer_mode timer_reason timer_reason_text owner_username stages teams team_action_lists
       ]
       expect(json.keys).to match_array(expected_keys)
       expect(json[:name]).to eq(@tournament.name)
@@ -224,13 +224,20 @@ RSpec.describe TournamentsController, type: :controller do
   describe 'GET #timer' do
     it 'returns timer state in ISO 8601 format' do
       timestamp = Time.utc(2026, 4, 13, 18, 0, 0)
-      @tournament.update!(timestamp: timestamp, timer_mode: 'countdown')
+      @tournament.update!(
+        timestamp: timestamp,
+        timer_mode: 'countdown',
+        timer_reason: 'custom',
+        timer_reason_text: 'Opening ceremony'
+      )
 
       get :timer, params: { id: @tournament.to_param }
 
       expect(response).to be_successful
       expect(deserialize_response(response)[:timestamp]).to eq(timestamp.iso8601)
       expect(deserialize_response(response)[:timer_mode]).to eq('countdown')
+      expect(deserialize_response(response)[:timer_reason]).to eq('custom')
+      expect(deserialize_response(response)[:timer_reason_text]).to eq('Opening ceremony')
     end
   end
 
@@ -242,35 +249,60 @@ RSpec.describe TournamentsController, type: :controller do
     it 'stores timezone-aware timestamp values without shifting them' do
       timestamp = '2030-04-13T18:00:00+02:00'
 
-      patch :set_timer, params: { id: @tournament.to_param, timestamp: timestamp }
+      patch :set_timer, params: {
+        id: @tournament.to_param,
+        timestamp: timestamp,
+        timer_reason: 'tournament_start'
+      }
 
       expect(response).to be_successful
       expect(@tournament.reload.timestamp.iso8601).to eq(Time.iso8601(timestamp).utc.iso8601)
+      expect(@tournament.timer_reason).to eq('tournament_start')
+      expect(@tournament.timer_reason_text).to be_nil
       expect(deserialize_response(response)[:timestamp]).to eq(@tournament.timestamp.iso8601)
       expect(deserialize_response(response)[:timer_mode]).to eq('countdown')
+      expect(deserialize_response(response)[:timer_reason]).to eq('tournament_start')
     end
 
     it 'starts countup timer at current time when timer_mode=countup' do
       before_request = Time.zone.now
 
-      patch :set_timer, params: { id: @tournament.to_param, timer_mode: 'countup' }
+      patch :set_timer, params: {
+        id: @tournament.to_param,
+        timer_mode: 'countup',
+        timer_reason: 'custom',
+        timer_reason_text: 'Tie-break delay'
+      }
 
       expect(response).to be_successful
       expect(@tournament.reload.timer_mode).to eq('countup')
+      expect(@tournament.timer_reason).to eq('custom')
+      expect(@tournament.timer_reason_text).to eq('Tie-break delay')
       expect(@tournament.timestamp).to be_between(before_request - 1.second, Time.zone.now + 1.second)
       expect(deserialize_response(response)[:timer_mode]).to eq('countup')
+      expect(deserialize_response(response)[:timer_reason]).to eq('custom')
+      expect(deserialize_response(response)[:timer_reason_text]).to eq('Tie-break delay')
     end
 
     it 'clears timer state when clear_timer=true' do
-      @tournament.update!(timestamp: Time.utc(2030, 4, 13, 18, 0, 0), timer_mode: 'countdown')
+      @tournament.update!(
+        timestamp: Time.utc(2030, 4, 13, 18, 0, 0),
+        timer_mode: 'countdown',
+        timer_reason: 'custom',
+        timer_reason_text: 'Warm-up pause'
+      )
 
       patch :set_timer, params: { id: @tournament.to_param, clear_timer: true }
 
       expect(response).to be_successful
       expect(@tournament.reload.timestamp).to be_nil
       expect(@tournament.timer_mode).to be_nil
+      expect(@tournament.timer_reason).to be_nil
+      expect(@tournament.timer_reason_text).to be_nil
       expect(deserialize_response(response)[:timestamp]).to be_nil
       expect(deserialize_response(response)[:timer_mode]).to be_nil
+      expect(deserialize_response(response)[:timer_reason]).to be_nil
+      expect(deserialize_response(response)[:timer_reason_text]).to be_nil
     end
 
     it 'rejects timestamp_seconds for countup mode' do
@@ -279,6 +311,34 @@ RSpec.describe TournamentsController, type: :controller do
       expect(response).to have_http_status(:unprocessable_entity)
       expect(deserialize_response(response)[:error]).to eq('timestamp_seconds is only allowed for countdown mode')
     end
+
+    it 'rejects invalid timer reason values' do
+      patch :set_timer, params: { id: @tournament.to_param, timestamp_seconds: 120, timer_reason: 'ceremony' }
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(deserialize_response(response)[:error]).to eq('Invalid timer_reason')
+    end
+
+    it 'requires timer_reason_text for custom timer reason' do
+      patch :set_timer, params: { id: @tournament.to_param, timestamp_seconds: 120, timer_reason: 'custom' }
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(deserialize_response(response)[:error]).to eq('timer_reason_text is required for custom timer_reason')
+    end
+
+    it 'rejects timer_reason_text for predefined timer reasons' do
+      patch :set_timer, params: {
+        id: @tournament.to_param,
+        timestamp_seconds: 120,
+        timer_reason: 'match_end',
+        timer_reason_text: 'Extra info'
+      }
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(deserialize_response(response)[:error]).to eq(
+        'timer_reason_text is only allowed when timer_reason is custom'
+      )
+    end
   end
 
   describe 'POST #create' do
diff --git a/spec/e2e/http/api_surface_spec.rb b/spec/e2e/http/api_surface_spec.rb
index 2c1b5ed..8575991 100644
--- a/spec/e2e/http/api_surface_spec.rb
+++ b/spec/e2e/http/api_surface_spec.rb
@@ -134,15 +134,32 @@ RSpec.describe 'Backend API surface HTTP E2E' do
     forbidden_update = other_client.patch("/tournaments/#{tournament.fetch(:id)}", body: { name: 'Not Allowed' })
     unauthenticated_update = anonymous_client.patch("/tournaments/#{tournament.fetch(:id)}", body: { name: 'No Auth' })
 
-    timer_seconds = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: { timestamp_seconds: 120 })
+    timer_seconds = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: {
+                                         timestamp_seconds: 120,
+                                         timer_reason: 'tournament_start'
+                                       })
     timer_show = anonymous_client.get("/tournaments/#{tournament.fetch(:id)}/timer")
-    timer_countup = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: { timer_mode: 'countup' })
+    timer_countup = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: {
+                                         timer_mode: 'countup',
+                                         timer_reason: 'custom',
+                                         timer_reason_text: 'Pause ran long'
+                                       })
     timer_clear = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: { clear_timer: true })
     timer_double = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: {
                                         timestamp_seconds: 120,
                                         timestamp: (Time.now.utc + 240).iso8601
                                       })
-    timer_invalid_seconds = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: { timestamp_seconds: 'nope' })
+    timer_invalid_reason = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: {
+                                                timestamp_seconds: 120,
+                                                timer_reason: 'ceremony'
+                                              })
+    timer_custom_without_text = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: {
+                                                    timestamp_seconds: 120,
+                                                    timer_reason: 'custom'
+                                                  })
+    timer_invalid_seconds = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: {
+                                                 timestamp_seconds: 'nope'
+                                               })
     timer_past = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: { timestamp_seconds: 0 })
     timer_countup_seconds = owner_client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: {
                                                  timer_mode: 'countup',
@@ -171,18 +188,31 @@ RSpec.describe 'Backend API surface HTTP E2E' do
     expect(timer_seconds[:status]).to eq(200)
     expect(timer_seconds.dig(:json, :timestamp)).to be_a(String)
     expect(timer_seconds.dig(:json, :timer_mode)).to eq('countdown')
+    expect(timer_seconds.dig(:json, :timer_reason)).to eq('tournament_start')
+    expect(timer_seconds.dig(:json, :timer_reason_text)).to be_nil
     expect(timer_show[:status]).to eq(200)
     expect(timer_show.dig(:json, :timestamp)).to eq(timer_seconds.dig(:json, :timestamp))
     expect(timer_show.dig(:json, :timer_mode)).to eq('countdown')
+    expect(timer_show.dig(:json, :timer_reason)).to eq('tournament_start')
     expect(timer_countup[:status]).to eq(200)
     expect(timer_countup.dig(:json, :timestamp)).to be_a(String)
     expect(timer_countup.dig(:json, :timer_mode)).to eq('countup')
+    expect(timer_countup.dig(:json, :timer_reason)).to eq('custom')
+    expect(timer_countup.dig(:json, :timer_reason_text)).to eq('Pause ran long')
     expect(timer_clear[:status]).to eq(200)
     expect(timer_clear.dig(:json, :timestamp)).to be_nil
     expect(timer_clear.dig(:json, :timer_mode)).to be_nil
+    expect(timer_clear.dig(:json, :timer_reason)).to be_nil
+    expect(timer_clear.dig(:json, :timer_reason_text)).to be_nil
 
     expect(timer_double[:status]).to eq(422)
     expect(timer_double.dig(:json, :error)).to eq('Only one of timestamp or timestamp_seconds is allowed')
+    expect(timer_invalid_reason[:status]).to eq(422)
+    expect(timer_invalid_reason.dig(:json, :error)).to eq('Invalid timer_reason')
+    expect(timer_custom_without_text[:status]).to eq(422)
+    expect(timer_custom_without_text.dig(:json, :error)).to eq(
+      'timer_reason_text is required for custom timer_reason'
+    )
     expect(timer_invalid_seconds[:status]).to eq(422)
     expect(timer_invalid_seconds.dig(:json, :error)).to eq('Invalid seconds format')
     expect(timer_past[:status]).to eq(422)
diff --git a/spec/e2e/http/tournament_follow_sync_spec.rb b/spec/e2e/http/tournament_follow_sync_spec.rb
index 1800ad6..aa3f87c 100644
--- a/spec/e2e/http/tournament_follow_sync_spec.rb
+++ b/spec/e2e/http/tournament_follow_sync_spec.rb
@@ -504,6 +504,9 @@ RSpec.describe 'Tournament follower sync HTTP E2E' do
       instant_finalists_amount: tournament.fetch(:instant_finalists_amount),
       intermediate_round_participants_amount: tournament.fetch(:intermediate_round_participants_amount),
       timestamp: tournament[:timestamp],
+      timer_mode: tournament[:timer_mode],
+      timer_reason: tournament[:timer_reason],
+      timer_reason_text: tournament[:timer_reason_text],
       teams: tournament.fetch(:teams).map { |team| team.slice(:name, :advancing_from_group_stage) }.sort_by { |team| team.fetch(:name) },
       team_action_lists: tournament.fetch(:team_action_lists, []).sort_by { |list| list.fetch(:key) }.map do |list|
         {
diff --git a/spec/e2e/http/tournament_timer_follow_sync_websocket_spec.rb b/spec/e2e/http/tournament_timer_follow_sync_websocket_spec.rb
index 3b8c364..4112807 100644
--- a/spec/e2e/http/tournament_timer_follow_sync_websocket_spec.rb
+++ b/spec/e2e/http/tournament_timer_follow_sync_websocket_spec.rb
@@ -40,24 +40,42 @@ RSpec.describe 'Tournament timer follower sync websocket HTTP E2E' do
     initial_payload = cable_client.wait_for_timer_payload!
     expect(initial_payload.fetch('timestamp')).to be_nil
     expect(initial_payload.fetch('timer_mode')).to be_nil
+    expect(initial_payload.fetch('timer_reason')).to be_nil
+    expect(initial_payload.fetch('timer_reason_text')).to be_nil
 
-    countdown = source_client.patch("/tournaments/#{source.fetch(:id)}/timer", body: { timestamp_seconds: 120 })
+    countdown = source_client.patch("/tournaments/#{source.fetch(:id)}/timer", body: {
+                                      timestamp_seconds: 120,
+                                      timer_reason: 'match_end'
+                                    })
     expect(countdown[:status]).to eq(200)
+    sync_now_if_requested!(source.fetch(:id))
 
     countdown_payload = wait_for_timer_state!(cable_client, timer_mode: 'countdown')
     expect(countdown_payload.fetch('timestamp')).to eq(countdown.dig(:json, :timestamp))
+    expect(countdown_payload.fetch('timer_reason')).to eq('match_end')
+    expect(countdown_payload.fetch('timer_reason_text')).to be_nil
 
-    countup = source_client.patch("/tournaments/#{source.fetch(:id)}/timer", body: { timer_mode: 'countup' })
+    countup = source_client.patch("/tournaments/#{source.fetch(:id)}/timer", body: {
+                                    timer_mode: 'countup',
+                                    timer_reason: 'custom',
+                                    timer_reason_text: 'Follower sync custom reason'
+                                  })
     expect(countup[:status]).to eq(200)
+    sync_now_if_requested!(source.fetch(:id))
 
     countup_payload = wait_for_timer_state!(cable_client, timer_mode: 'countup')
     expect(countup_payload.fetch('timestamp')).to eq(countup.dig(:json, :timestamp))
+    expect(countup_payload.fetch('timer_reason')).to eq('custom')
+    expect(countup_payload.fetch('timer_reason_text')).to eq('Follower sync custom reason')
 
     clear = source_client.patch("/tournaments/#{source.fetch(:id)}/timer", body: { clear_timer: true })
     expect(clear[:status]).to eq(200)
+    sync_now_if_requested!(source.fetch(:id))
 
     cleared_payload = wait_for_timer_state!(cable_client, timer_mode: nil)
     expect(cleared_payload.fetch('timestamp')).to be_nil
+    expect(cleared_payload.fetch('timer_reason')).to be_nil
+    expect(cleared_payload.fetch('timer_reason_text')).to be_nil
   ensure
     cable_client&.close
   end
@@ -95,6 +113,13 @@ RSpec.describe 'Tournament timer follower sync websocket HTTP E2E' do
     response.fetch(:json)
   end
 
+  def sync_now_if_requested!(source_tournament_id)
+    return unless ENV.fetch('TURNIERE_E2E_SYNC_MODE', nil) == 'manual'
+
+    response = source_client.post("/tournaments/#{source_tournament_id}/test_sync")
+    expect(response[:status]).to eq(200)
+  end
+
   def wait_for_timer_state!(cable_client, timer_mode:, timeout: 20)
     deadline = Time.now + timeout
     loop do
diff --git a/spec/e2e/http/tournament_timer_websocket_spec.rb b/spec/e2e/http/tournament_timer_websocket_spec.rb
index 1431476..73913bb 100644
--- a/spec/e2e/http/tournament_timer_websocket_spec.rb
+++ b/spec/e2e/http/tournament_timer_websocket_spec.rb
@@ -31,24 +31,39 @@ RSpec.describe 'Tournament timer websocket HTTP E2E' do
     initial_payload = cable_client.wait_for_timer_payload!
     expect(initial_payload.fetch('timestamp')).to be_nil
     expect(initial_payload.fetch('timer_mode')).to be_nil
+    expect(initial_payload.fetch('timer_reason')).to be_nil
+    expect(initial_payload.fetch('timer_reason_text')).to be_nil
 
-    countdown = client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: { timestamp_seconds: 120 })
+    countdown = client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: {
+                               timestamp_seconds: 120,
+                               timer_reason: 'playoff_start'
+                             })
     expect(countdown[:status]).to eq(200)
 
     countdown_payload = wait_for_timer_state!(cable_client, timer_mode: 'countdown')
     expect(countdown_payload.fetch('timestamp')).to eq(countdown.dig(:json, :timestamp))
+    expect(countdown_payload.fetch('timer_reason')).to eq('playoff_start')
+    expect(countdown_payload.fetch('timer_reason_text')).to be_nil
 
-    countup = client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: { timer_mode: 'countup' })
+    countup = client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: {
+                             timer_mode: 'countup',
+                             timer_reason: 'custom',
+                             timer_reason_text: 'Manual overtime'
+                           })
     expect(countup[:status]).to eq(200)
 
     countup_payload = wait_for_timer_state!(cable_client, timer_mode: 'countup')
     expect(countup_payload.fetch('timestamp')).to eq(countup.dig(:json, :timestamp))
+    expect(countup_payload.fetch('timer_reason')).to eq('custom')
+    expect(countup_payload.fetch('timer_reason_text')).to eq('Manual overtime')
 
     clear = client.patch("/tournaments/#{tournament.fetch(:id)}/timer", body: { clear_timer: true })
     expect(clear[:status]).to eq(200)
 
     cleared_payload = wait_for_timer_state!(cable_client, timer_mode: nil)
     expect(cleared_payload.fetch('timestamp')).to be_nil
+    expect(cleared_payload.fetch('timer_reason')).to be_nil
+    expect(cleared_payload.fetch('timer_reason_text')).to be_nil
   ensure
     cable_client&.close
   end
diff --git a/spec/services/tournament_live_payload_spec.rb b/spec/services/tournament_live_payload_spec.rb
index cd91ab4..21cb34b 100644
--- a/spec/services/tournament_live_payload_spec.rb
+++ b/spec/services/tournament_live_payload_spec.rb
@@ -83,4 +83,27 @@ RSpec.describe 'Tournament live payloads' do
       expect(payload[:matches]).to eq(TournamentMatchesPayload.build(tournament, state: 'not_started'))
     end
   end
+
+  describe TournamentTimerBroadcastPayload do
+    it 'serializes timer reason fields for websocket subscribers' do
+      tournament = create(
+        :tournament,
+        timestamp: Time.utc(2026, 4, 24, 10, 15, 0),
+        timer_mode: 'countdown',
+        timer_reason: 'custom',
+        timer_reason_text: 'Opening ceremony'
+      )
+
+      payload = described_class.build(tournament)
+
+      expect(payload).to include(
+        type: 'timer.updated',
+        tournament_id: tournament.id,
+        timestamp: '2026-04-24T10:15:00Z',
+        timer_mode: 'countdown',
+        timer_reason: 'custom',
+        timer_reason_text: 'Opening ceremony'
+      )
+    end
+  end
 end
diff --git a/spec/services/tournament_snapshot_importer_spec.rb b/spec/services/tournament_snapshot_importer_spec.rb
index 03f9b1a..14f3795 100644
--- a/spec/services/tournament_snapshot_importer_spec.rb
+++ b/spec/services/tournament_snapshot_importer_spec.rb
@@ -6,6 +6,12 @@ RSpec.describe TournamentSnapshotImporter do
   describe '.import!' do
     it 'replaces follower tournament graph using source ids as stable mapping keys' do
       source = create(:group_stage_tournament, group_count: 2, match_factory: :filled_group_match)
+      source.update!(
+        timestamp: Time.utc(2026, 4, 24, 10, 15, 0),
+        timer_mode: 'countdown',
+        timer_reason: 'custom',
+        timer_reason_text: 'Opening ceremony'
+      )
       source.beamers.create!(
         name: 'stream-a',
         display_state: 'during_game',
@@ -23,6 +29,8 @@ RSpec.describe TournamentSnapshotImporter do
       expect(follower.sync_source_tournament_id).to eq(source.id)
       expect(follower.name).to eq(source.name)
       expect(follower.timer_mode).to eq(source.timer_mode)
+      expect(follower.timer_reason).to eq(source.timer_reason)
+      expect(follower.timer_reason_text).to eq(source.timer_reason_text)
       expect(follower.teams.count).to eq(snapshot.fetch(:teams).count)
       expect(follower.beamers.count).to eq(snapshot.fetch(:beamers).count)
       expect(follower.team_action_lists.count).to eq(snapshot.fetch(:team_action_lists).count)
@@ -127,6 +135,11 @@ RSpec.describe TournamentSnapshotImporter do
 
     tournament.reload
     play_some_playoff_matches!(tournament)
+    tournament.update!(
+      timestamp: Time.utc(2026, 4, 24, 10, 15, 0),
+      timer_mode: 'countdown',
+      timer_reason: 'playoff_start'
+    )
     tournament.reload
   end
 
@@ -186,6 +199,8 @@ RSpec.describe TournamentSnapshotImporter do
       intermediate_round_participants_amount: tournament.intermediate_round_participants_amount,
       timestamp: tournament.timestamp&.iso8601,
       timer_mode: tournament.timer_mode,
+      timer_reason: tournament.timer_reason,
+      timer_reason_text: tournament.timer_reason_text,
       teams: tournament.teams.order(:name).map { |team| team.name },
       team_action_lists: tournament.team_action_lists.order(:key).map do |list|
         {
diff --git a/tasks.py b/tasks.py
index 3bb5306..69986f7 100644
--- a/tasks.py
+++ b/tasks.py
@@ -525,7 +525,7 @@ def _run_blackbox_rspec(base_url, email, password, username, alt_email=E2E_ALT_E
 def _start_server(command, env, log_path="/tmp/turniere-e2e-server.log"):
     log_handle = open(log_path, "w")
     process = subprocess.Popen(
-        ["/bin/sh", "-lc", command],
+        ["/bin/sh", "-c", command],
         env=env,
         stdout=log_handle,
         stderr=subprocess.STDOUT,