diff --git a/bootstrap.sh b/bootstrap.sh
index 713677a..5c3fd4c 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -18,7 +18,7 @@ pacman-key --init
 pacman --sync --refresh --noconfirm --sysupgrade
 pacman --sync --refresh --noconfirm mkosi git base-devel ukify vim cpio tree \
     rsync btrfs-progs s3cmd dosfstools qemu-img erofs-utils squashfs-tools go openssh \
-    compsize
+    compsize duperemove
 
 # Use mkosi from git to not have to wait for releases when things break.
 # OTOH things may break in git. So which version is used may change over time.
diff --git a/btrfs-send-receive.sh b/btrfs-send-receive.sh
index 4dedd60..bf80595 100755
--- a/btrfs-send-receive.sh
+++ b/btrfs-send-receive.sh
@@ -25,7 +25,7 @@ cleanup() {
 trap cleanup INT TERM EXIT
 cleanup
 
-mount -o remount,compress-force=zstd:8 "$PWD"
+mount -o remount,compress-force=zstd:15 "$PWD"
 btrfs property set . compression zstd
 btrfs balance start --force -mconvert=single -dconvert=single .
 
@@ -44,4 +44,22 @@ btrfs subvolume snapshot -r "$EXPORT.live" "@live"
 btrfs subvolume delete "$EXPORT.live"
 rm -f "$OUTPUT_ABS.btrfs.live"
 
+# Finally let's condense the data.
+btrfs filesystem usage .
+## Use duperemove to deduplicate files.
+## I would also love to use bees here as it works on extents but we don't know when it is done :( https://github.com/Zygo/bees/issues/279
+duperemove -dr .
+## Balance the filesystem with ever increasing chunk sizes to maximize space efficiency.
+btrfs balance start --force -mconvert=single -dconvert=single .
+btrfs balance start --force -dusage=16 .
+btrfs balance start --force -dusage=32 .
+btrfs balance start --force -dusage=64 .
+## And to finish things off we shrink the filesystem to the minimum size.
+./btrfs-shrink.py
+mv btrfs.json "$(dirname "$OUTPUT_ABS")/btrfs.json"
+## Sync changes to disk.
+btrfs filesystem sync .
+# Final report.
+btrfs filesystem usage .
+
 ln -svf "@$OUTPUT" "$ID"
diff --git a/btrfs-shrink.py b/btrfs-shrink.py
new file mode 100644
index 0000000..bb77be0
--- /dev/null
+++ b/btrfs-shrink.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+
+# SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+# SPDX-FileCopyrightText: 2024 Harald Sitter <sitter@kde.org>
+
+# Shrink btrfs. It's a bit awkward because we don't really have a reliable way
+# to calculate how much space we actually need. So we first chop off a dynamic
+# portion but leave a bit of a buffer behind. Then we keep resizing until the
+# resize starts failing.
+
+import json
+import subprocess
+from subprocess import check_output
+
+out = check_output(["btrfs", "--format", "json", "filesystem", "df", "."])
+data = json.loads(out)
+df = data["filesystem-df"]
+
+size = 0
+for block_group in df:
+    size += block_group["total"]
+
+# Give 512MiB of buffer space. We'll shrink from there in smaller steps.
+size += 512 * 1024 * 1024
+
+subprocess.run(["btrfs", "filesystem", "resize", str(size), "."])
+
+# With compression one extent is always 128KiB as per btrfs documentation.
+extent_size = 128 * 1024
+while True:
+    try:
+        subprocess.run(["btrfs", "filesystem", "resize", f"-{extent_size}", "."], stdout=subprocess.DEVNULL, stdin=subprocess.DEVNULL, check=True)
+        size -= extent_size
+    except subprocess.CalledProcessError as e:
+        print(e)
+        break
+
+with open("btrfs.json", "w") as file:
+    # Writing data to a file
+    file.write(json.dumps({"size": size}))