diff --git a/ci/README.md b/ci/README.md
index 7fcda96e3480..66fb707ebec5 100644
--- a/ci/README.md
+++ b/ci/README.md
@@ -7,9 +7,9 @@ This is in contrast with [`maintainers/scripts`](../maintainers/scripts) which i
 
 CI may need certain packages from Nixpkgs.
 In order to ensure that the needed packages are generally available without building,
-[`pinned-nixpkgs.json`](./pinned-nixpkgs.json) contains a pinned Nixpkgs version tested by Hydra.
+[`pinned.json`](./pinned.json) contains a pinned Nixpkgs version tested by Hydra.
 
-Run [`update-pinned-nixpkgs.sh`](./update-pinned-nixpkgs.sh) to update it.
+Run [`update-pinned.sh`](./update-pinned.sh) to update it.
 
 ## `ci/nixpkgs-vet.sh BASE_BRANCH [REPOSITORY]`
 
@@ -20,23 +20,3 @@ Arguments:
 
 - `BASE_BRANCH`: The base branch to use, e.g. master or release-24.05
 - `REPOSITORY`: The repository from which to fetch the base branch. Defaults to <https://github.com/NixOS/nixpkgs.git>.
-
-## `ci/nixpkgs-vet`
-
-This directory contains scripts and files used and related to [`nixpkgs-vet`](https://github.com/NixOS/nixpkgs-vet/), which the CI uses to implement `pkgs/by-name` checks, along with many other Nixpkgs architecture rules.
-See also the [CI GitHub Action](../.github/workflows/nixpkgs-vet.yml).
-
-## `ci/nixpkgs-vet/update-pinned-tool.sh`
-
-Updates the pinned [`nixpkgs-vet` tool](https://github.com/NixOS/nixpkgs-vet) in [`ci/nixpkgs-vet/pinned-version.txt`](./nixpkgs-vet/pinned-version.txt) to the latest [release](https://github.com/NixOS/nixpkgs-vet/releases).
-
-Each release contains a pre-built `x86_64-linux` version of the tool which is used by CI.
-
-This script currently needs to be called manually when the CI tooling needs to be updated.
-
-Why not just build the tooling right from the PRs Nixpkgs version?
-
-- Because it allows CI to check all PRs, even if they would break the CI tooling.
-- Because it makes the CI check very fast, since no Nix builds need to be done, even for mass rebuilds.
-- Because it improves security, since we don't have to build potentially untrusted code from PRs.
-  The tool only needs a very minimal Nix evaluation at runtime, which can work with [readonly-mode](https://nixos.org/manual/nix/stable/command-ref/opt-common.html#opt-readonly-mode) and [restrict-eval](https://nixos.org/manual/nix/stable/command-ref/conf-file.html#conf-restrict-eval).
diff --git a/ci/default.nix b/ci/default.nix
index 94d049903fca..ec35121bb24b 100644
--- a/ci/default.nix
+++ b/ci/default.nix
@@ -1,5 +1,5 @@
 let
-  pinnedNixpkgs = builtins.fromJSON (builtins.readFile ./pinned-nixpkgs.json);
+  pinned = (builtins.fromJSON (builtins.readFile ./pinned.json)).pins;
 in
 {
   system ? builtins.currentSystem,
@@ -10,8 +10,8 @@ let
   nixpkgs' =
     if nixpkgs == null then
       fetchTarball {
-        url = "https://github.com/NixOS/nixpkgs/archive/${pinnedNixpkgs.rev}.tar.gz";
-        sha256 = pinnedNixpkgs.sha256;
+        inherit (pinned.nixpkgs) url;
+        sha256 = pinned.nixpkgs.hash;
       }
     else
       nixpkgs;
@@ -25,9 +25,8 @@ let
   fmt =
     let
       treefmtNixSrc = fetchTarball {
-        # Master at 2025-02-12
-        url = "https://github.com/numtide/treefmt-nix/archive/4f09b473c936d41582dd744e19f34ec27592c5fd.tar.gz";
-        sha256 = "051vh6raskrxw5k6jncm8zbk9fhbzgm1gxpq9gm5xw1b6wgbgcna";
+        inherit (pinned.treefmt-nix) url;
+        sha256 = pinned.treefmt-nix.hash;
       };
       treefmtEval = (import treefmtNixSrc).evalModule pkgs {
         # Important: The auto-rebase script uses `git filter-branch --tree-filter`,
diff --git a/ci/nixpkgs-vet.sh b/ci/nixpkgs-vet.sh
index b62e04fe0177..8ad2a35adfa0 100755
--- a/ci/nixpkgs-vet.sh
+++ b/ci/nixpkgs-vet.sh
@@ -61,9 +61,6 @@ trace "Done"
 trace -n "Merging base branch into the HEAD commit in $tmp/merged.. "
 git -C "$tmp/merged" merge -q --no-edit "$baseSha"
 trace -e "\e[34m$(git -C "$tmp/merged" rev-parse HEAD)\e[0m"
-trace -n "Reading pinned nixpkgs-vet version from pinned-version.txt.. "
-toolVersion=$(<"$tmp/merged/ci/nixpkgs-vet/pinned-version.txt")
-trace -e "\e[34m$toolVersion\e[0m"
 
 trace "Running nixpkgs-vet.."
 nix-build ci -A nixpkgs-vet --argstr base "$tmp/base" --argstr head "$tmp/merged"
diff --git a/ci/nixpkgs-vet/pinned-version.txt b/ci/nixpkgs-vet/pinned-version.txt
deleted file mode 100644
index 845639eef26c..000000000000
--- a/ci/nixpkgs-vet/pinned-version.txt
+++ /dev/null
@@ -1 +0,0 @@
-0.1.4
diff --git a/ci/nixpkgs-vet/update-pinned-tool.sh b/ci/nixpkgs-vet/update-pinned-tool.sh
deleted file mode 100755
index 78a9ae2411b8..000000000000
--- a/ci/nixpkgs-vet/update-pinned-tool.sh
+++ /dev/null
@@ -1,22 +0,0 @@
-#!/usr/bin/env nix-shell
-#!nix-shell -i bash -p jq curl
-
-set -o pipefail -o errexit -o nounset
-
-trace() { echo >&2 "$@"; }
-
-SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
-
-repository=NixOS/nixpkgs-vet
-pin_file=$SCRIPT_DIR/pinned-version.txt
-
-trace -n "Fetching latest release of $repository.. "
-latestRelease=$(curl -sSfL \
-  -H "Accept: application/vnd.github+json" \
-  -H "X-GitHub-Api-Version: 2022-11-28" \
-  https://api.github.com/repos/"$repository"/releases/latest)
-latestVersion=$(jq .tag_name -r <<< "$latestRelease")
-trace "$latestVersion"
-
-trace "Updating $pin_file"
-echo "$latestVersion" > "$pin_file"
diff --git a/ci/pinned-nixpkgs.json b/ci/pinned-nixpkgs.json
deleted file mode 100644
index 7a9596380c41..000000000000
--- a/ci/pinned-nixpkgs.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "rev": "3d1f29646e4b57ed468d60f9d286cde23a8d1707",
-  "sha256": "1wzvc9h9a6l9wyhzh892xb5x88kxmbzxb1k8s7fizyyw2q4nqw07"
-}
diff --git a/ci/pinned.json b/ci/pinned.json
new file mode 100644
index 000000000000..f29d17f7aa6c
--- /dev/null
+++ b/ci/pinned.json
@@ -0,0 +1,31 @@
+{
+  "pins": {
+    "nixpkgs": {
+      "type": "Git",
+      "repository": {
+        "type": "GitHub",
+        "owner": "NixOS",
+        "repo": "nixpkgs"
+      },
+      "branch": "nixpkgs-unstable",
+      "submodules": false,
+      "revision": "8ca7ec685bbee55d6dcb326abe23945c0806c39e",
+      "url": "https://github.com/NixOS/nixpkgs/archive/8ca7ec685bbee55d6dcb326abe23945c0806c39e.tar.gz",
+      "hash": "1hkxm871m66mjsc4acdki32qqnpgk3n6vi3zrzns2bwlwp6ivcjx"
+    },
+    "treefmt-nix": {
+      "type": "Git",
+      "repository": {
+        "type": "GitHub",
+        "owner": "numtide",
+        "repo": "treefmt-nix"
+      },
+      "branch": "main",
+      "submodules": false,
+      "revision": "1f3f7b784643d488ba4bf315638b2b0a4c5fb007",
+      "url": "https://github.com/numtide/treefmt-nix/archive/1f3f7b784643d488ba4bf315638b2b0a4c5fb007.tar.gz",
+      "hash": "13qisjalw9qvd6lkd9g8225r46j5wdjrp3zw6jrs81q2vxwdz37m"
+    }
+  },
+  "version": 5
+}
diff --git a/ci/update-pinned-nixpkgs.sh b/ci/update-pinned-nixpkgs.sh
deleted file mode 100755
index d44b59d80ede..000000000000
--- a/ci/update-pinned-nixpkgs.sh
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/usr/bin/env nix-shell
-#!nix-shell -i bash -p jq
-
-set -euo pipefail
-
-# https://stackoverflow.com/a/246128
-SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
-
-repo=https://github.com/nixos/nixpkgs
-branch=nixpkgs-unstable
-file=$SCRIPT_DIR/pinned-nixpkgs.json
-
-defaultRev=$(git ls-remote "$repo" refs/heads/"$branch" | cut -f1)
-rev=${1:-$defaultRev}
-sha256=$(nix-prefetch-url --unpack "$repo/archive/$rev.tar.gz" --name source)
-
-jq -n --arg rev "$rev" --arg sha256 "$sha256" '$ARGS.named' | tee /dev/stderr > $file
diff --git a/ci/update-pinned.sh b/ci/update-pinned.sh
new file mode 100755
index 000000000000..7e3a26695fe8
--- /dev/null
+++ b/ci/update-pinned.sh
@@ -0,0 +1,8 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p npins
+
+set -euo pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")"
+
+npins --lock-file pinned.json update