diff --git a/tools/diawi/install_pr_build.py b/tools/diawi/install_pr_build.py
new file mode 100755
index 0000000000..32f250ceed
--- /dev/null
+++ b/tools/diawi/install_pr_build.py
@@ -0,0 +1,237 @@
+#!/usr/bin/env python3
+"""
+Install the Diawi build attached to a GitHub PR onto a connected Android device.
+
+Usage:
+    ./install_pr_build.py https://github.com/element-hq/element-x-android/pull/7750
+    ./install_pr_build.py <pr_url> --serial emulator-5554 --replace
+
+Steps:
+  1. Reads the PR description and comments through the GitHub API and finds the
+     most recent link of the form https://i.diawi.com/<build_id>.
+  2. Scrapes the Diawi page and finds the link labeled "Download application".
+  3. Downloads the APK.
+  4. Runs `adb install <apk_path>`.
+
+Set GITHUB_TOKEN in the environment to avoid GitHub's anonymous rate limit
+(60 requests/hour). Only the Python standard library is used.
+"""
+
+import argparse
+import json
+import os
+import re
+import shutil
+import subprocess
+import sys
+import tempfile
+import urllib.error
+import urllib.request
+from html.parser import HTMLParser
+from urllib.parse import urljoin
+
+PR_URL_RE = re.compile(r"https?://github\.com/([^/]+)/([^/]+)/pull/(\d+)")
+DIAWI_RE = re.compile(r"https://i\.diawi\.com/([A-Za-z0-9]+)")
+DOWNLOAD_LABEL = "download application"
+USER_AGENT = (
+    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
+    "(KHTML, like Gecko) Chrome/128.0 Safari/537.36"
+)
+
+
+def die(msg: str) -> None:
+    print(f"error: {msg}", file=sys.stderr)
+    sys.exit(1)
+
+
+def http_get(url: str, headers: dict | None = None) -> urllib.request.addinfourl:
+    req = urllib.request.Request(url, headers={"User-Agent": USER_AGENT, **(headers or {})})
+    try:
+        return urllib.request.urlopen(req, timeout=60)
+    except urllib.error.HTTPError as e:
+        die(f"HTTP {e.code} while fetching {url}")
+    except urllib.error.URLError as e:
+        die(f"could not reach {url}: {e.reason}")
+
+
+# --------------------------------------------------------------------------- #
+# 1. Find the Diawi link in the PR
+# --------------------------------------------------------------------------- #
+def github_json(url: str):
+    headers = {"Accept": "application/vnd.github+json"}
+    token = os.environ.get("GITHUB_TOKEN")
+    if token:
+        headers["Authorization"] = f"Bearer {token}"
+    with http_get(url, headers) as resp:
+        return json.load(resp), resp.headers.get("Link", "")
+
+
+def find_diawi_link(pr_url: str) -> str:
+    m = PR_URL_RE.match(pr_url)
+    if not m:
+        die(f"not a GitHub PR URL: {pr_url}")
+    owner, repo, number = m.groups()
+    api = f"https://api.github.com/repos/{owner}/{repo}"
+
+    texts = []
+    pr, _ = github_json(f"{api}/pulls/{number}")
+    texts.append(pr.get("body") or "")
+
+    # Comments are returned oldest first; follow pagination to get them all.
+    url = f"{api}/issues/{number}/comments?per_page=100"
+    while url:
+        comments, link_header = github_json(url)
+        texts.extend(c.get("body") or "" for c in comments)
+        nxt = re.search(r'<([^>]+)>;\s*rel="next"', link_header)
+        url = nxt.group(1) if nxt else None
+
+    links = [f"https://i.diawi.com/{bid}" for t in texts for bid in DIAWI_RE.findall(t)]
+    if not links:
+        die("no https://i.diawi.com/<build_id> link found in the PR")
+    return links[-1]  # most recent one
+
+
+# --------------------------------------------------------------------------- #
+# 2. Scrape the Diawi page for the "Download application" link
+# --------------------------------------------------------------------------- #
+class LinkCollector(HTMLParser):
+    """Collects (href, visible text) for every <a> tag."""
+
+    def __init__(self):
+        super().__init__()
+        self.links: list[tuple[str, str]] = []
+        self._href: str | None = None
+        self._text: list[str] = []
+
+    def handle_starttag(self, tag, attrs):
+        if tag == "a":
+            self._href = dict(attrs).get("href")
+            self._text = []
+
+    def handle_data(self, data):
+        if self._href is not None:
+            self._text.append(data)
+
+    def handle_endtag(self, tag):
+        if tag == "a" and self._href is not None:
+            text = " ".join("".join(self._text).split())
+            self.links.append((self._href, text))
+            self._href = None
+
+
+def find_apk_url(diawi_url: str) -> str:
+    with http_get(diawi_url) as resp:
+        html = resp.read().decode(resp.headers.get_content_charset() or "utf-8", "replace")
+
+    parser = LinkCollector()
+    parser.feed(html)
+
+    for href, text in parser.links:
+        if href and DOWNLOAD_LABEL in text.lower():
+            return urljoin(diawi_url, href)
+
+    # Fallback: anything that looks like a direct APK link.
+    for href, _ in parser.links:
+        if href and ".apk" in href.lower():
+            return urljoin(diawi_url, href)
+
+    die(f"no 'Download application' link found on {diawi_url} "
+        "(the build may have expired)")
+
+
+# --------------------------------------------------------------------------- #
+# 3. Download the APK
+# --------------------------------------------------------------------------- #
+def download(url: str, dest: str) -> None:
+    with http_get(url) as resp, open(dest, "wb") as out:
+        total = int(resp.headers.get("Content-Length") or 0)
+        done = 0
+        while chunk := resp.read(1 << 16):
+            out.write(chunk)
+            done += len(chunk)
+            if total:
+                print(f"\r  {done * 100 // total:3d}%  {done / 1e6:.1f} MB", end="", flush=True)
+    print()
+
+    with open(dest, "rb") as f:
+        if f.read(2) != b"PK":  # APKs are zip archives
+            die("downloaded file is not an APK (Diawi may have returned an HTML page)")
+
+
+# --------------------------------------------------------------------------- #
+# 4. Install with adb
+# --------------------------------------------------------------------------- #
+def adb_install(apk: str, serial: str | None, replace: bool) -> int:
+    if not shutil.which("adb"):
+        die("adb not found in PATH")
+    adb = ["adb"] + (["-s", serial] if serial else [])
+
+    devices = subprocess.run(["adb", "devices"], capture_output=True, text=True).stdout
+    attached = [l for l in devices.splitlines()[1:] if l.strip().endswith("device")]
+    if not attached:
+        die("no Android device connected (check `adb devices`)")
+
+    cmd = adb + ["install"] + (["-r"] if replace else []) + [apk]
+    print("Running:", " ".join(cmd))
+    return subprocess.run(cmd).returncode
+
+def adb_launch(serial: str | None) -> int:
+    if not shutil.which("adb"):
+        die("adb not found in PATH")
+    adb = ["adb"] + (["-s", serial] if serial else [])
+
+    devices = subprocess.run(["adb", "devices"], capture_output=True, text=True).stdout
+    attached = [l for l in devices.splitlines()[1:] if l.strip().endswith("device")]
+    if not attached:
+        die("no Android device connected (check `adb devices`)")
+
+    cmd = adb + ["shell", "am", "start", "-n", "io.element.android.x.debug/io.element.android.x.MainActivity"]
+
+    print("Running:", " ".join(cmd))
+    return subprocess.run(cmd).returncode
+
+def main() -> None:
+    ap = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    ap.add_argument("pr_url", help="GitHub PR URL or PR number (e.g. 7750)")
+    ap.add_argument("-s", "--serial", help="device serial, if several devices are connected")
+    ap.add_argument("-r", "--replace", action="store_true", help="pass -r to adb install (reinstall, keep data)")
+    ap.add_argument("-o", "--output", help="where to save the APK (default: temp dir, deleted afterwards)")
+    args = ap.parse_args()
+
+    if args.pr_url.isdigit():
+        pr_url = f"https://github.com/element-hq/element-x-android/pull/{args.pr_url}"
+    else:
+        pr_url = args.pr_url
+    print(f"Looking for a Diawi link in {pr_url} ...")
+    diawi_url = find_diawi_link(pr_url)
+    print(f"Found: {diawi_url}")
+
+    apk_url = find_apk_url(diawi_url)
+    print(f"APK link: {apk_url}")
+
+    build_id = diawi_url.rsplit("/", 1)[-1]
+    if args.output:
+        apk_path = args.output
+        tmpdir = None
+    else:
+        tmpdir = tempfile.mkdtemp(prefix="diawi-")
+        apk_path = os.path.join(tmpdir, f"{build_id}.apk")
+
+    print(f"Downloading to {apk_path} ...")
+    try:
+        download(apk_url, apk_path)
+        if adb_install(apk_path, args.serial, args.replace) == 0:
+            print("Installed successfully.")
+        else:
+            die("adb install failed.")
+        if adb_launch(args.serial) == 0:
+            print("Launched successfully.")
+        else:
+            die("adb launch failed.")
+    finally:
+        if tmpdir:
+            shutil.rmtree(tmpdir, ignore_errors=True)
+
+
+if __name__ == "__main__":
+    main()