diff --git a/app/controllers/Fide.scala b/app/controllers/Fide.scala
index decb90ea1da86..e025b28afc0a7 100644
--- a/app/controllers/Fide.scala
+++ b/app/controllers/Fide.scala
@@ -25,11 +25,17 @@ final class Fide(env: Env) extends LilaController(env):
           if player.slug != slug then Redirect(routes.Fide.show(id, player.slug))
           else
             for
-              user     <- env.title.api.publicUserOf(player.id)
-              tours    <- env.relay.playerTour.playerTours(player, page)
-              rendered <- renderPage(views.fide.player.show(player, user, tours))
+              user        <- env.title.api.publicUserOf(player.id)
+              tours       <- env.relay.playerTour.playerTours(player, page)
+              isFollowing <- ctx.me.soFu(me => env.fide.repo.follower.isFollowing(me.userId, id))
+              rendered    <- renderPage(views.fide.player.show(player, user, tours, isFollowing))
             yield Ok(rendered)
 
+  def follow(fideId: chess.FideId, follow: Boolean) = AuthBody: _ ?=>
+    me ?=>
+      val f = if follow then env.fide.repo.follower.follow else env.fide.repo.follower.unfollow
+      for _ <- f(me.userId, fideId) yield NoContent
+
   def apiShow(id: chess.FideId) = Anon:
     Found(env.fide.repo.player.fetch(id))(JsonOk)
 
diff --git a/app/views/fide.scala b/app/views/fide.scala
index 6a8411805c353..a03f338dc0d25 100644
--- a/app/views/fide.scala
+++ b/app/views/fide.scala
@@ -12,11 +12,18 @@ export ui.federation
 object player:
   export ui.player.{ index, notFound }
 
-  def show(player: FidePlayer, user: Option[User], tours: Paginator[RelayTour.WithLastRound])(using Context) =
+  def show(
+      player: FidePlayer,
+      user: Option[User],
+      tours: Paginator[RelayTour.WithLastRound],
+      isFollowing: Option[Boolean]
+  )(using Context) =
     ui.player.show(
       player,
       user,
       (tours.nbResults > 0).option:
         views.relay.tour.renderPager(views.relay.tour.asRelayPager(tours)):
           routes.Fide.show(player.id, player.slug, _)
+      ,
+      isFollowing
     )
diff --git a/conf/routes b/conf/routes
index e4ce14593ec04..7335241c61d74 100644
--- a/conf/routes
+++ b/conf/routes
@@ -114,6 +114,7 @@ GET   /fide                            controllers.Fide.index(page: Int ?= 1, q:
 GET   /fide/federation                 controllers.Fide.federations(page: Int ?= 1)
 GET   /fide/federation/:name           controllers.Fide.federation(name, page: Int ?= 1)
 GET   /fide/:fideId/:name              controllers.Fide.show(fideId: chess.FideId, name, page: Int ?= 1)
+POST  /fide/:fideId/follow             controllers.Fide.follow(fideId: chess.FideId, follow: Boolean)
 GET   /api/fide/player/:id             controllers.Fide.apiShow(id: chess.FideId)
 GET   /api/fide/player                 controllers.Fide.apiSearch(q: String)
 
diff --git a/modules/coach/src/main/ui/CoachUi.scala b/modules/coach/src/main/ui/CoachUi.scala
index ba08f4813bfd0..33aaeacf1cfae 100644
--- a/modules/coach/src/main/ui/CoachUi.scala
+++ b/modules/coach/src/main/ui/CoachUi.scala
@@ -6,7 +6,7 @@ import scalalib.paginator.Paginator
 
 import lila.core.config.NetDomain
 import lila.core.data.RichText
-import lila.core.user.{ Flag, FlagCode, Profile }
+import lila.core.user.{ Flag, Profile }
 import lila.rating.UserPerfsExt.{ best6Perfs, hasEstablishedRating }
 import lila.ui.*
 
diff --git a/modules/core/src/main/fide.scala b/modules/core/src/main/fide.scala
index 5174a8c5a0f6b..8a8b6f0f36f4e 100644
--- a/modules/core/src/main/fide.scala
+++ b/modules/core/src/main/fide.scala
@@ -3,6 +3,7 @@ package fide
 
 import _root_.chess.{ FideId, PlayerName, PlayerTitle }
 import _root_.chess.rating.{ Elo, KFactor }
+import lila.core.userId.UserId
 
 enum FideTC:
   case standard, rapid, blitz
@@ -29,9 +30,10 @@ trait Player:
   def kFactorOf(tc: FideTC): KFactor
   def ratingsMap: Map[FideTC, Elo]
 
-type PlayerToken = String
-type GuessPlayer = (Option[FideId], Option[PlayerName], Option[PlayerTitle]) => Fu[Option[Player]]
-type GetPlayer   = FideId => Fu[Option[Player]]
+type PlayerToken        = String
+type GuessPlayer        = (Option[FideId], Option[PlayerName], Option[PlayerTitle]) => Fu[Option[Player]]
+type GetPlayer          = FideId => Fu[Option[Player]]
+type GetPlayerFollowers = FideId => Fu[List[UserId]]
 
 type Tokenize = String => PlayerToken
 
diff --git a/modules/fide/src/main/Env.scala b/modules/fide/src/main/Env.scala
index d320dea4b566f..10c788b9e81c5 100644
--- a/modules/fide/src/main/Env.scala
+++ b/modules/fide/src/main/Env.scala
@@ -15,7 +15,11 @@ final class Env(db: lila.db.Db, cacheApi: CacheApi, ws: StandaloneWSClient)(usin
 )(using mode: play.api.Mode, scheduler: Scheduler):
 
   val repo =
-    FideRepo(playerColl = db(CollName("fide_player")), federationColl = db(CollName("fide_federation")))
+    FideRepo(
+      playerColl = db(CollName("fide_player")),
+      federationColl = db(CollName("fide_federation")),
+      followerColl = db(CollName("fide_player_follower"))
+    )
 
   lazy val playerApi = wire[FidePlayerApi]
 
@@ -23,11 +27,12 @@ final class Env(db: lila.db.Db, cacheApi: CacheApi, ws: StandaloneWSClient)(usin
 
   lazy val paginator = wire[FidePaginator]
 
-  def federationsOf: hub.Federation.FedsOf      = playerApi.federationsOf
-  def federationNamesOf: hub.Federation.NamesOf = playerApi.federationNamesOf
-  def tokenize: hub.Tokenize                    = FidePlayer.tokenize
-  def guessPlayer: hub.GuessPlayer              = playerApi.guessPlayer.apply
-  def getPlayer: hub.GetPlayer                  = playerApi.get
+  def federationsOf: hub.Federation.FedsOf       = playerApi.federationsOf
+  def federationNamesOf: hub.Federation.NamesOf  = playerApi.federationNamesOf
+  def tokenize: hub.Tokenize                     = FidePlayer.tokenize
+  def guessPlayer: hub.GuessPlayer               = playerApi.guessPlayer.apply
+  def getPlayer: hub.GetPlayer                   = playerApi.get
+  def getPlayerFollowers: hub.GetPlayerFollowers = repo.follower.followers
 
   def search(q: Option[String], page: Int = 1): Fu[Either[FidePlayer, Paginator[FidePlayer]]] =
     val query = q.so(_.trim)
diff --git a/modules/fide/src/main/FideRepo.scala b/modules/fide/src/main/FideRepo.scala
index 192b414acd776..9cbd6043b77aa 100644
--- a/modules/fide/src/main/FideRepo.scala
+++ b/modules/fide/src/main/FideRepo.scala
@@ -5,10 +5,12 @@ import reactivemongo.api.bson.*
 
 import lila.core.fide as hub
 import lila.db.dsl.{ *, given }
+import scala.util.Success
 
 final private class FideRepo(
     private[fide] val playerColl: Coll,
-    private[fide] val federationColl: Coll
+    private[fide] val federationColl: Coll,
+    private val followerColl: Coll
 )(using Executor):
 
   object player:
@@ -27,3 +29,15 @@ final private class FideRepo(
     def upsert(fed: Federation): Funit              =
       federationColl.update.one($id(fed.id), fed, upsert = true).void
     def fetch(code: hub.Federation.Id): Fu[Option[Federation]] = federationColl.byId[Federation](code)
+
+  object follower:
+    private def makeId(u: UserId, p: FideId)   = s"$p/$u"
+    def followers(p: FideId): Fu[List[UserId]] =
+      for ids <- followerColl.distinctEasy[String, List]("_id", "_id".$startsWith(s"$p/"))
+      yield UserId.from(ids.map(id => id.drop(id.indexOf('/') + 1)))
+    def follow(u: UserId, p: FideId) = playerColl
+      .exists($id(p))
+      .flatMapz:
+        followerColl.update.one($id(makeId(u, p)), $doc("u" -> u), upsert = true).void
+    def unfollow(u: UserId, p: FideId)    = followerColl.delete.one($id(makeId(u, p))).void
+    def isFollowing(u: UserId, p: FideId) = followerColl.exists($id(makeId(u, p)))
diff --git a/modules/fide/src/main/ui/FideUi.scala b/modules/fide/src/main/ui/FideUi.scala
index 81618e86cdf8b..54d9759cef8e3 100644
--- a/modules/fide/src/main/ui/FideUi.scala
+++ b/modules/fide/src/main/ui/FideUi.scala
@@ -22,7 +22,7 @@ final class FideUi(helpers: Helpers)(menu: String => Context ?=> Frag):
   private def page(title: String, active: String)(modifiers: Modifier*)(using Context): Page =
     Page(title)
       .css("bits.fide")
-      .js(infiniteScrollEsmInit):
+      .js(infiniteScrollEsmInit ++ esmInitBit("fidePlayerFollow")):
         main(cls := "page-menu")(
           menu(active),
           div(cls := "page-menu__content box")(modifiers)
@@ -186,12 +186,29 @@ final class FideUi(helpers: Helpers)(menu: String => Context ?=> Frag):
     private def card(name: Frag, value: Frag) =
       div(cls := "fide-card fide-player__card")(em(name), strong(value))
 
-    def show(player: FidePlayer, user: Option[User], tours: Option[Frag])(using Context) =
+    private def followButton(player: FidePlayer, isFollowing: Boolean)(using Context) =
+      val id = "fide-player-follow"
+      label(cls := "fide-player__follow")(
+        form3.cmnToggle(
+          fieldId = id,
+          fieldName = id,
+          checked = isFollowing,
+          action = Some(routes.Fide.follow(player.id, isFollowing).url)
+        ),
+        trans.site.follow()
+      )
+
+    def show(player: FidePlayer, user: Option[User], tours: Option[Frag], isFollowing: Option[Boolean])(using
+        Context
+    ) =
       page(s"${player.name} - FIDE player ${player.id}", "players")(
         cls := "box-pad fide-player",
-        h1(
-          span(titleTag(player.title), player.name),
-          user.map(userLink(_, withTitle = false)(cls := "fide-player__user"))
+        div(cls := "fide-player__header")(
+          h1(
+            span(titleTag(player.title), player.name),
+            user.map(userLink(_, withTitle = false)(cls := "fide-player__user"))
+          ),
+          isFollowing.map(followButton(player, _))
         ),
         div(cls := "fide-cards fide-player__cards")(
           player.fed.map: fed =>
diff --git a/modules/relay/src/main/Env.scala b/modules/relay/src/main/Env.scala
index 91ef55480c1a6..10af638f4de7a 100644
--- a/modules/relay/src/main/Env.scala
+++ b/modules/relay/src/main/Env.scala
@@ -31,6 +31,7 @@ final class Env(
     gameProxy: lila.core.game.GameProxy,
     guessPlayer: lila.core.fide.GuessPlayer,
     getPlayer: lila.core.fide.GetPlayer,
+    getPlayerFollowers: lila.core.fide.GetPlayerFollowers,
     cacheApi: lila.memo.CacheApi,
     settingStore: SettingStore.Builder,
     irc: lila.core.irc.IrcApi,
diff --git a/modules/relay/src/main/RelayGame.scala b/modules/relay/src/main/RelayGame.scala
index 78589424c5e58..cfa108e7698ef 100644
--- a/modules/relay/src/main/RelayGame.scala
+++ b/modules/relay/src/main/RelayGame.scala
@@ -30,8 +30,11 @@ case class RelayGame(
     points = None
   )
 
+  def fideIds: chess.ByColor[Option[chess.FideId]] =
+    tags.fideIds.map(_.filter(_.value > 0))
+
   def fideIdsPair: Option[PairOf[Option[chess.FideId]]] =
-    tags.fideIds.some.filter(_.forall(_.exists(_.value > 0))).map(_.toPair)
+    fideIds.some.filter(_.forall(_.isDefined)).map(_.toPair)
 
   def hasUnknownPlayer: Boolean =
     List(RelayGame.whiteTags, RelayGame.blackTags).exists:
diff --git a/modules/relay/src/main/RelayNotifier.scala b/modules/relay/src/main/RelayNotifier.scala
index ebf9ad73d680f..38bfde0f95fe7 100644
--- a/modules/relay/src/main/RelayNotifier.scala
+++ b/modules/relay/src/main/RelayNotifier.scala
@@ -1,19 +1,52 @@
 package lila.relay
 
+import scalalib.cache.OnceEvery
+
 import lila.core.notify.{ NotifyApi, NotificationContent }
+import lila.study.Chapter
+
+final private class RelayNotifier(
+    notifyApi: NotifyApi,
+    tourRepo: RelayTourRepo,
+    getPlayerFollowers: lila.core.fide.GetPlayerFollowers
+)(using Executor):
+
+  private object notifyPlayerFollowers:
+
+    private val dedupNotif = OnceEvery[StudyChapterId](1.day)
+
+    def apply(rt: RelayRound.WithTour, chapter: Chapter, game: RelayGame): Funit =
+      dedupNotif(chapter.id).so:
+        val futureByColor = game.fideIds.mapWithColor: (color, fid) =>
+          for
+            followers <- fid.so(getPlayerFollowers)
+            notify    <- followers.nonEmpty.so:
+              chapter.tags.names.sequence.so: names =>
+                notifyApi.notifyMany(
+                  followers,
+                  NotificationContent.BroadcastRound(
+                    url = rt.path(chapter.id),
+                    title = rt.tour.name.value,
+                    text = s"${names(color)} is playing against ${names(!color)} in ${rt.round.name}"
+                  )
+                )
+          yield notify
+        Future.sequence(futureByColor.all).void
 
-final private class RelayNotifier(notifyApi: NotifyApi, tourRepo: RelayTourRepo)(using Executor):
-
-  def roundBegin(rt: RelayRound.WithTour): Funit =
-    tourRepo
-      .hasNotified(rt)
-      .not
-      .flatMapz:
-        tourRepo.setNotified(rt) >>
-          tourRepo
-            .subscribers(rt.tour.id)
-            .flatMap: subscribers =>
-              subscribers.nonEmpty.so:
+  private object notifyTournamentSubscribers:
+
+    private val dedupDbReq = OnceEvery[RelayRoundId](5.minutes)
+
+    def apply(rt: RelayRound.WithTour): Funit =
+      dedupDbReq(rt.round.id).so:
+        tourRepo
+          .hasNotified(rt)
+          .not
+          .flatMapz:
+            for
+              _           <- tourRepo.setNotified(rt)
+              subscribers <- tourRepo.subscribers(rt.tour.id)
+              _           <- subscribers.nonEmpty.so:
                 notifyApi.notifyMany(
                   subscribers,
                   NotificationContent.BroadcastRound(
@@ -22,3 +55,8 @@ final private class RelayNotifier(notifyApi: NotifyApi, tourRepo: RelayTourRepo)
                     s"${rt.round.name} has begun"
                   )
                 )
+            yield ()
+
+  def chapterUpdated(rt: RelayRound.WithTour, chapter: Chapter, game: RelayGame): Unit =
+    notifyPlayerFollowers(rt, chapter, game)
+    notifyTournamentSubscribers(rt)
diff --git a/modules/relay/src/main/RelaySync.scala b/modules/relay/src/main/RelaySync.scala
index 2133c021bd98d..6b95bdc2c8506 100644
--- a/modules/relay/src/main/RelaySync.scala
+++ b/modules/relay/src/main/RelaySync.scala
@@ -51,7 +51,7 @@ final private class RelaySync(
     chapter             <- updateInitialPosition(study.id, chapter, game)
     (tagUpdate, newEnd) <- updateChapterTags(rt.tour, study, chapter, game)
     nbMoves             <- updateChapterTree(study, chapter, game)(using rt.tour)
-    _                   <- (nbMoves > 0).so(notifier.roundBegin(rt))
+    _ = if nbMoves > 0 then notifier.chapterUpdated(rt, chapter, game)
   yield SyncResult.ChapterResult(chapter.id, tagUpdate, nbMoves, newEnd)
 
   private def createChapter(
diff --git a/modules/relay/src/main/RelayTourRepo.scala b/modules/relay/src/main/RelayTourRepo.scala
index a8f585749c051..2684b897a55ae 100644
--- a/modules/relay/src/main/RelayTourRepo.scala
+++ b/modules/relay/src/main/RelayTourRepo.scala
@@ -42,7 +42,7 @@ final private class RelayTourRepo(val coll: Coll)(using Executor):
   def countBySubscriberId(uid: UserId): Fu[Int] =
     coll.countSel(selectors.subscriberId(uid))
 
-  def hasNotified(rt: RelayRound.WithTour): Fu[Boolean] =
+  private[relay] def hasNotified(rt: RelayRound.WithTour): Fu[Boolean] =
     coll.exists($doc($id(rt.tour.id), "notified" -> rt.round.id))
 
   def setNotified(rt: RelayRound.WithTour): Funit =
diff --git a/modules/streamer/src/main/ui/StreamerBits.scala b/modules/streamer/src/main/ui/StreamerBits.scala
index e8582b6a023b6..500ff45eb6ffa 100644
--- a/modules/streamer/src/main/ui/StreamerBits.scala
+++ b/modules/streamer/src/main/ui/StreamerBits.scala
@@ -191,7 +191,6 @@ final class StreamerBits(helpers: Helpers)(picfitUrl: lila.core.misc.PicfitUrl):
     (ctx.isAuth && ctx.isnt(s.user)).option:
       val id = s"streamer-subscribe-${s.streamer.userId}"
       label(cls := "streamer-subscribe")(
-        `for`          := id,
         data("action") := s"${routes.Streamer.subscribe(s.streamer.userId, !s.subscribed)}"
       )(
         span(
diff --git a/modules/ui/src/main/helper/Form3.scala b/modules/ui/src/main/helper/Form3.scala
index 66f25ae58f148..ad02d196194f7 100644
--- a/modules/ui/src/main/helper/Form3.scala
+++ b/modules/ui/src/main/helper/Form3.scala
@@ -94,7 +94,8 @@ final class Form3(formHelper: FormHelper & I18nHelper & AssetHelper, flairApi: F
       checked: Boolean,
       disabled: Boolean = false,
       value: Value = "true",
-      title: Option[String] = None
+      title: Option[String] = None,
+      action: Option[String] = None
   ) =
     frag(
       (disabled && checked).option: // disabled checkboxes don't submit; need an extra hidden field
@@ -107,7 +108,8 @@ final class Form3(formHelper: FormHelper & I18nHelper & AssetHelper, flairApi: F
         tpe      := "checkbox",
         cls      := "form-control cmn-toggle",
         checked.option(st.checked),
-        disabled.option(st.disabled)
+        disabled.option(st.disabled),
+        action.map(st.data("action") := _)
       ),
       label(
         `for` := fieldId,
diff --git a/ui/bits/css/_fide.scss b/ui/bits/css/_fide.scss
index a01647fc78210..51943c3451981 100644
--- a/ui/bits/css/_fide.scss
+++ b/ui/bits/css/_fide.scss
@@ -106,6 +106,14 @@
     align-items: center;
     gap: 1em;
   }
+  &__header {
+    @extend %flex-between-nowrap;
+  }
+  &__follow {
+    @extend %flex-center-nowrap;
+    gap: 1ch;
+    cursor: pointer;
+  }
   &__user {
     font-size: 0.7em;
   }
diff --git a/ui/bits/css/build/bits.fide.scss b/ui/bits/css/build/bits.fide.scss
index 3a1340703513c..900d79fe6a415 100644
--- a/ui/bits/css/build/bits.fide.scss
+++ b/ui/bits/css/build/bits.fide.scss
@@ -1,4 +1,5 @@
 @import '../../../lib/css/plugin';
+@import '../../../lib/css/form/cmn-toggle';
 @import '../../../lib/css/component/slist';
 @import '../relay/relay';
 
diff --git a/ui/bits/css/streamer/_header.scss b/ui/bits/css/streamer/_header.scss
index 087e134ee4aa9..a7490ca29dddc 100644
--- a/ui/bits/css/streamer/_header.scss
+++ b/ui/bits/css/streamer/_header.scss
@@ -134,6 +134,7 @@
   align-self: flex-start;
   font-weight: bold;
   z-index: $z-link-overlay-2;
+  cursor: pointer;
 }
 
 .streamer-profile {
diff --git a/ui/bits/src/bits.ts b/ui/bits/src/bits.ts
index 7b92567d3d5cb..4a41bd385318f 100644
--- a/ui/bits/src/bits.ts
+++ b/ui/bits/src/bits.ts
@@ -2,6 +2,7 @@ import { text, formToXhr } from 'lib/xhr';
 import flairPickerLoader from './flairPicker';
 import { spinnerHtml } from 'lib/view/controls';
 import { wireCropDialog } from './crop';
+import { debounce } from 'lib/async';
 
 // avoid node_modules and pay attention to imports here. we don't want to force people
 // to download the entire toastui editor library just to do some light form processing.
@@ -34,6 +35,8 @@ export function initModule(args: { fn: string } & any): void {
       return setAssetInfo();
     case 'streamerSubscribe':
       return streamerSubscribe();
+    case 'fidePlayerFollow':
+      return fidePlayerFollow();
     case 'thanksReport':
       return thanksReport();
     case 'titleRequest':
@@ -233,6 +236,19 @@ function streamerSubscribe() {
   });
 }
 
+function fidePlayerFollow() {
+  const el = $('#fide-player-follow');
+  el.on(
+    'change',
+    debounce(
+      () =>
+        text(el.data('action').replace(/follow=[^&]+/, `follow=${el.prop('checked')}`), { method: 'post' }),
+      1000,
+      true,
+    ),
+  );
+}
+
 function titleRequest() {
   $('.title-image-edit').each(function (this: HTMLElement) {
     wireCropDialog({