diff --git a/.env.sample b/.env.sample
index b919531..6a81ae3 100644
--- a/.env.sample
+++ b/.env.sample
@@ -76,6 +76,10 @@ ENCRYPTED_BY_DEFAULT=all
 #TRACK_PUPPETED_USER_IPS=true
 
 
+## Room complexity limit (prevents joining large remote rooms that cause DB bloat)
+## complexity ≈ state_events / 500. Default 100.0 blocks rooms with >50000 state events.
+#ROOM_COMPLEXITY_LIMIT=100.0
+
 ## Retention
 
 ALLOWED_LIFETIME_MAX=4w
@@ -199,6 +203,14 @@ RETENTION_MAX_LIFETIME=4w
 #WEB_CLIENT_LOCATION=https://element-web.example.com
 
 
+## State compression (reduces database bloat from federation)
+## Runs synapse_auto_compressor daily, built from source on first start
+#COMPOSE_FILE="$COMPOSE_FILE:compose.compress-state.yml"
+# See https://github.com/matrix-org/rust-synapse-compress-state#running-options
+#STATE_COMPRESS_CHUNK_SIZE=500
+#STATE_COMPRESS_CHUNKS=100
+#STATE_COMPRESS_SCHEDULE=0 3 * * *
+
 ## Admin interface at /admin
 #COMPOSE_FILE="$COMPOSE_FILE:compose.admin.yml"
 #ADMIN_INTERFACE_ENABLED=1
diff --git a/abra.sh b/abra.sh
index 5009278..4f90829 100644
--- a/abra.sh
+++ b/abra.sh
@@ -1,6 +1,6 @@
 export DISCORD_BRIDGE_YAML_VERSION=v2
 export ENTRYPOINT_CONF_VERSION=v3
-export HOMESERVER_YAML_VERSION=v35
+export HOMESERVER_YAML_VERSION=v36
 export LOG_CONFIG_VERSION=v2
 export SHARED_SECRET_AUTH_VERSION=v2
 export SIGNAL_BRIDGE_YAML_VERSION=v6
@@ -10,6 +10,213 @@ export WK_SERVER_VERSION=v1
 export WK_CLIENT_VERSION=v1
 export PG_BACKUP_VERSION=v2
 export ADMIN_CONFIG_VERSION=v1
+export COMPRESS_STATE_ENTRYPOINT_VERSION=v5
+
+###############################################################################
+# Database maintenance — shrink a bloated Synapse database
+#
+# See https://levans.fr/shrink-synapse-database.html
+#
+# Recommended steps to reclaim disk space:
+#   1. abra app cmd <domain> compress-state run_compressor 500 10000
+#      (compress redundant state — safe while Synapse is running)
+#   2. abra app cmd <domain> db reindex
+#      (rebuild indexes — stop Synapse first)
+#   3. abra app cmd <domain> db vacuum_full
+#      (rewrite tables and reclaim disk — stop Synapse first)
+#
+# Diagnostic commands (safe to run anytime):
+#   abra app cmd <domain> db db_size
+#   abra app cmd <domain> db state_bloat
+#   abra app cmd <domain> db empty_rooms
+#
+# Purge commands (require an admin token):
+#   abra app cmd <domain> app register_admin <user> <pass>
+#   abra app cmd <domain> app get_token <user> <pass>
+#   abra app cmd <domain> app purge_remote_media <days> <token>
+#   abra app cmd <domain> app purge_empty_rooms <token>
+#   abra app cmd <domain> app purge_room <room_id> <token>
+#   abra app cmd <domain> app purge_history <room_id> <days> <token>
+###############################################################################
+
+# --- Diagnostics (db) ---
+
+db_size() {
+    echo "=== Database size ==="
+    psql -U synapse -d synapse -c "SELECT pg_size_pretty(pg_database_size('synapse')) AS db_size;"
+    echo ""
+    echo "=== Top 10 largest tables ==="
+    psql -U synapse -d synapse -c "
+        SELECT nspname || '.' || relname AS table,
+               pg_size_pretty(pg_total_relation_size(C.oid)) AS total_size
+        FROM pg_class C
+        LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace)
+        WHERE nspname NOT IN ('pg_catalog', 'information_schema')
+        ORDER BY pg_total_relation_size(C.oid) DESC
+        LIMIT 10;"
+}
+
+state_bloat() {
+    echo "=== Rooms with most state bloat ==="
+    psql -U synapse -d synapse -c "
+        SELECT room_id, count(*) AS state_entries
+        FROM state_groups_state
+        GROUP BY room_id
+        ORDER BY state_entries DESC
+        LIMIT 20;"
+}
+
+empty_rooms() {
+    echo "=== Rooms with no local members ==="
+    psql -U synapse -d synapse -c "
+        SELECT room_id, room_version
+        FROM rooms
+        WHERE room_id NOT IN (
+            SELECT room_id FROM local_current_membership WHERE membership = 'join'
+        );"
+}
+
+# --- Compression (compress-state) ---
+
+run_compressor() {
+    CHUNK_SIZE="${1:-${STATE_COMPRESS_CHUNK_SIZE:-500}}"
+    CHUNKS="${2:-${STATE_COMPRESS_CHUNKS:-100}}"
+    DB_PASS=$(cat /run/secrets/db_password)
+    echo "Running synapse_auto_compressor (chunk_size=$CHUNK_SIZE, chunks=$CHUNKS)..."
+    /build/synapse_auto_compressor \
+        -p "postgresql://synapse:${DB_PASS}@db:5432/synapse" \
+        -c "$CHUNK_SIZE" -n "$CHUNKS"
+}
+
+# --- Maintenance (db) — stop Synapse before running these ---
+
+reindex() {
+    echo "WARNING: REINDEX locks tables. Synapse should be stopped before running this."
+    echo "Running REINDEX on synapse database..."
+    psql -U synapse -d synapse -c "REINDEX (VERBOSE) DATABASE synapse;"
+    echo "REINDEX complete."
+    psql -U synapse -d synapse -c "SELECT pg_size_pretty(pg_database_size('synapse')) AS db_size;"
+}
+
+vacuum_full() {
+    echo "WARNING: VACUUM FULL locks tables and requires temporary disk space."
+    echo "Synapse should be stopped before running this."
+    echo "Running VACUUM FULL on synapse database..."
+    psql -U synapse -d synapse -c "VACUUM FULL;"
+    echo "VACUUM FULL complete."
+    psql -U synapse -d synapse -c "SELECT pg_size_pretty(pg_database_size('synapse')) AS db_size;"
+}
+
+# --- Purge commands (app) — require an admin access token ---
+
+register_admin() {
+    USER="${1}"
+    PASS="${2}"
+    if [ -z "$USER" ] || [ -z "$PASS" ]; then
+        echo "Usage: register_admin <username> <password>"
+        return 1
+    fi
+    register_new_matrix_user -u "$USER" -p "$PASS" -a -c /data/homeserver.yaml http://localhost:8008
+}
+
+get_token() {
+    USER="${1}"
+    PASS="${2}"
+    if [ -z "$USER" ] || [ -z "$PASS" ]; then
+        echo "Usage: get_token <username> <password>"
+        echo "Returns an admin access token for use with purge commands."
+        return 1
+    fi
+    curl -s -X POST "http://localhost:8008/_matrix/client/r0/login" \
+        -H "Content-Type: application/json" \
+        -d "{\"type\":\"m.login.password\",\"user\":\"$USER\",\"password\":\"$PASS\"}" \
+        | python3 -c "import sys,json; d=json.load(sys.stdin); print(d.get('access_token', d.get('error', 'unknown error')))"
+}
+
+purge_remote_media() {
+    DAYS="${1:-30}"
+    TOKEN="${2}"
+    if [ -z "$TOKEN" ]; then
+        echo "Usage: purge_remote_media <days> <admin_token>"
+        return 1
+    fi
+    BEFORE_TS=$(( $(date +%s) * 1000 - DAYS * 86400000 ))
+    echo "Purging remote media older than $DAYS days..."
+    curl -s -X POST "http://localhost:8008/_synapse/admin/v1/purge_media_cache?before_ts=$BEFORE_TS" \
+        -H "Authorization: Bearer $TOKEN"
+    echo ""
+}
+
+purge_room() {
+    ROOM_ID="${1}"
+    TOKEN="${2}"
+    if [ -z "$ROOM_ID" ] || [ -z "$TOKEN" ]; then
+        echo "Usage: purge_room <room_id> <admin_token>"
+        return 1
+    fi
+    echo "Purging room $ROOM_ID..."
+    curl -s -X DELETE "http://localhost:8008/_synapse/admin/v1/rooms/$ROOM_ID" \
+        -H "Authorization: Bearer $TOKEN" \
+        -H "Content-Type: application/json" \
+        -d '{"purge": true}'
+    echo ""
+}
+
+purge_history() {
+    ROOM_ID="${1}"
+    DAYS="${2:-90}"
+    TOKEN="${3}"
+    if [ -z "$ROOM_ID" ] || [ -z "$TOKEN" ]; then
+        echo "Usage: purge_history <room_id> <days> <admin_token>"
+        return 1
+    fi
+    BEFORE_TS=$(( $(date +%s) * 1000 - DAYS * 86400000 ))
+    echo "Purging history older than $DAYS days from $ROOM_ID..."
+    curl -s -X POST "http://localhost:8008/_synapse/admin/v1/purge_history/$ROOM_ID" \
+        -H "Authorization: Bearer $TOKEN" \
+        -H "Content-Type: application/json" \
+        -d "{\"purge_up_to_ts\": $BEFORE_TS}"
+    echo ""
+}
+
+purge_empty_rooms() {
+    TOKEN="${1}"
+    if [ -z "$TOKEN" ]; then
+        echo "Usage: purge_empty_rooms <admin_token>"
+        return 1
+    fi
+    echo "Fetching rooms with no local members..."
+    ROOMS=$(curl -s "http://localhost:8008/_synapse/admin/v1/rooms?limit=1000" \
+        -H "Authorization: Bearer $TOKEN" \
+        | python3 -c "
+import sys, json
+data = json.load(sys.stdin)
+for r in data.get('rooms', []):
+    if r.get('joined_local_members', 0) == 0:
+        print(r['room_id'])
+")
+    COUNT=$(echo "$ROOMS" | grep -c '.' || true)
+    echo "Found $COUNT empty rooms."
+    if [ "$COUNT" -eq 0 ]; then
+        echo "Nothing to purge."
+        return 0
+    fi
+    echo "$ROOMS"
+    echo ""
+    echo "Purging..."
+    for ROOM_ID in $ROOMS; do
+        echo "  Purging $ROOM_ID"
+        curl -s -X DELETE "http://localhost:8008/_synapse/admin/v1/rooms/$ROOM_ID" \
+            -H "Authorization: Bearer $TOKEN" \
+            -H "Content-Type: application/json" \
+            -d '{"purge": true}' > /dev/null
+    done
+    echo "Done."
+}
+
+###############################################################################
+# Other commands
+###############################################################################
 
 set_admin () {
     admin=akadmin
diff --git a/compose.compress-state.yml b/compose.compress-state.yml
new file mode 100644
index 0000000..1ddd8e1
--- /dev/null
+++ b/compose.compress-state.yml
@@ -0,0 +1,31 @@
+version: "3.8"
+
+services:
+  compress-state:
+    image: rust:1-alpine
+    entrypoint: /compress_state_entrypoint.sh
+    environment:
+      - STATE_COMPRESS_CHUNK_SIZE=${STATE_COMPRESS_CHUNK_SIZE:-500}
+      - STATE_COMPRESS_CHUNKS=${STATE_COMPRESS_CHUNKS:-100}
+      - STATE_COMPRESS_SCHEDULE=${STATE_COMPRESS_SCHEDULE:-0 3 * * *}
+    secrets:
+      - db_password
+    configs:
+      - source: compress_entrypoint
+        target: /compress_state_entrypoint.sh
+        mode: 0555
+    volumes:
+      - compress_state_build:/build
+    networks:
+      - internal
+    deploy:
+      restart_policy:
+        condition: on-failure
+
+volumes:
+  compress_state_build:
+
+configs:
+  compress_entrypoint:
+    name: ${STACK_NAME}_compress_ep_${COMPRESS_STATE_ENTRYPOINT_VERSION}
+    file: compress_state_entrypoint.sh
diff --git a/compose.yml b/compose.yml
index a9209f6..0cc6bd7 100644
--- a/compose.yml
+++ b/compose.yml
@@ -90,6 +90,7 @@ services:
       - LOGIN_LIMIT_IP_BURST=${LOGIN_LIMIT_IP_BURST:-5}
       - LOGIN_LIMIT_ACCOUNT_PER_SECOND=${LOGIN_LIMIT_ACCOUNT_PER_SECOND:-0.003}
       - LOGIN_LIMIT_ACCOUNT_BURST=${LOGIN_LIMIT_ACCOUNT_BURST:-5}
+      - ROOM_COMPLEXITY_LIMIT=${ROOM_COMPLEXITY_LIMIT:-100.0}
       - WEB_CLIENT_LOCATION
     networks:
       - internal
diff --git a/compress_state_entrypoint.sh b/compress_state_entrypoint.sh
new file mode 100644
index 0000000..7df067b
--- /dev/null
+++ b/compress_state_entrypoint.sh
@@ -0,0 +1,46 @@
+#!/bin/sh
+set -e
+
+BINARY="/build/synapse_auto_compressor"
+REPO_DIR="/build/rust-synapse-compress-state"
+DB_PASS=$(cat /run/secrets/db_password)
+CONN="postgresql://synapse:${DB_PASS}@db:5432/synapse"
+CHUNK_SIZE="${STATE_COMPRESS_CHUNK_SIZE:-500}"
+CHUNKS="${STATE_COMPRESS_CHUNKS:-100}"
+SCHEDULE="${STATE_COMPRESS_SCHEDULE:-0 3 * * *}"
+
+# Build from source if binary doesn't exist
+if [ ! -f "$BINARY" ]; then
+  echo "[compress-state] Binary not found, building from source..."
+  apk add --no-cache git openssl-dev openssl-libs-static perl make musl-dev jemalloc-dev
+  rm -rf "$REPO_DIR"
+  git clone https://github.com/matrix-org/rust-synapse-compress-state "$REPO_DIR"
+  cd "$REPO_DIR"
+  cargo build --release -p synapse_auto_compressor
+  cp target/release/synapse_auto_compressor "$BINARY"
+  echo "[compress-state] Build complete"
+  # Clean up source to save space
+  rm -rf "$REPO_DIR"
+else
+  echo "[compress-state] Using cached binary"
+fi
+
+# Run once at startup
+echo "[compress-state] Running initial compression at $(date)"
+"$BINARY" -p "$CONN" -c "$CHUNK_SIZE" -n "$CHUNKS" || echo "[compress-state] Error: $?"
+
+# Set up cron job
+CRON_SCRIPT="/build/run_compressor.sh"
+cat > "$CRON_SCRIPT" <<EOF
+#!/bin/sh
+echo "[compress-state] Running at \$(date)"
+$BINARY -p "$CONN" -c $CHUNK_SIZE -n $CHUNKS || echo "[compress-state] Error: \$?"
+echo "[compress-state] Done at \$(date)"
+EOF
+chmod +x "$CRON_SCRIPT"
+
+echo "$SCHEDULE $CRON_SCRIPT" | crontab -
+echo "[compress-state] Cron scheduled: $SCHEDULE"
+
+# Run crond in the foreground
+exec crond -f -l 2
diff --git a/homeserver.yaml.tmpl b/homeserver.yaml.tmpl
index 0fb7002..e51e2d7 100644
--- a/homeserver.yaml.tmpl
+++ b/homeserver.yaml.tmpl
@@ -69,7 +69,7 @@ admin_contact: 'mailto:{{ env "ADMIN_EMAIL" }}'
 # https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#limit_remote_rooms
 limit_remote_rooms:
   enabled: true
-  complexity: 200.0
+  complexity: {{ env "ROOM_COMPLEXITY_LIMIT" }}
 
 # https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#max_avatar_size
 max_avatar_size: 10M