diff --git a/pkgs/by-name/sl/slack/package.nix b/pkgs/by-name/sl/slack/package.nix
index ce2ec83cf9db..1ccc339a2409 100644
--- a/pkgs/by-name/sl/slack/package.nix
+++ b/pkgs/by-name/sl/slack/package.nix
@@ -7,46 +7,10 @@
 
 let
   inherit (stdenvNoCC.hostPlatform) system;
+  sources = import ./sources.nix { inherit fetchurl; };
 
   pname = "slack";
 
-  x86_64-darwin-version = "4.45.64";
-  x86_64-darwin-sha256 = "0skhh16lc0czxd5ifkqy39hibk4ydlfhn41zdif3hl0sd4vcqbvb";
-
-  x86_64-linux-version = "4.45.64";
-  x86_64-linux-sha256 = "7c6af86ab1d5778aec930d4e7d77b9f9948a83a87e8458e821d6f9e8dfed180f";
-
-  aarch64-darwin-version = "4.45.64";
-  aarch64-darwin-sha256 = "136crd17ybaznp680qb2rl0c8cllkkv21ymf3dck2jhkqbp7v2kj";
-
-  sources =
-    let
-      base = "https://downloads.slack-edge.com";
-    in
-    {
-      x86_64-darwin = rec {
-        version = x86_64-darwin-version;
-        src = fetchurl {
-          url = "${base}/desktop-releases/mac/universal/${version}/Slack-${version}-macOS.dmg";
-          sha256 = x86_64-darwin-sha256;
-        };
-      };
-      x86_64-linux = rec {
-        version = x86_64-linux-version;
-        src = fetchurl {
-          url = "${base}/desktop-releases/linux/x64/${version}/slack-desktop-${version}-amd64.deb";
-          sha256 = x86_64-linux-sha256;
-        };
-      };
-      aarch64-darwin = rec {
-        version = aarch64-darwin-version;
-        src = fetchurl {
-          url = "${base}/desktop-releases/mac/arm64/${version}/Slack-${version}-macOS.dmg";
-          sha256 = aarch64-darwin-sha256;
-        };
-      };
-    };
-
   passthru = {
     updateScript = ./update.sh;
   };
diff --git a/pkgs/by-name/sl/slack/sources.nix b/pkgs/by-name/sl/slack/sources.nix
new file mode 100644
index 000000000000..1042fd7b69c6
--- /dev/null
+++ b/pkgs/by-name/sl/slack/sources.nix
@@ -0,0 +1,26 @@
+# Generated by ./update.sh - do not update manually!
+# Last updated: 2025-08-29
+{ fetchurl }:
+{
+  aarch64-darwin = {
+    version = "4.45.64";
+    src = fetchurl {
+      url = "https://downloads.slack-edge.com/desktop-releases/mac/arm64/4.45.64/Slack-4.45.64-macOS.dmg";
+      hash = "sha256-cop97sITSjFZG676IPaclDLEAM1iYYDMtV8tf0LLzIw=";
+    };
+  };
+  x86_64-darwin = {
+    version = "4.45.64";
+    src = fetchurl {
+      url = "https://downloads.slack-edge.com/desktop-releases/mac/x64/4.45.64/Slack-4.45.64-macOS.dmg";
+      hash = "sha256-7SzSVM+2gtmsVwmoZUl3WQcI9si46nstbGUGXl+Yys8=";
+    };
+  };
+  x86_64-linux = {
+    version = "4.45.64";
+    src = fetchurl {
+      url = "https://downloads.slack-edge.com/desktop-releases/linux/x64/4.45.64/slack-desktop-4.45.64-amd64.deb";
+      hash = "sha256-fGr4arHVd4rskw1OfXe5+ZSKg6h+hFjoIdb56N/tGA8=";
+    };
+  };
+}
diff --git a/pkgs/by-name/sl/slack/update.sh b/pkgs/by-name/sl/slack/update.sh
index 9a47575b1e7a..c54a9a5e7c29 100755
--- a/pkgs/by-name/sl/slack/update.sh
+++ b/pkgs/by-name/sl/slack/update.sh
@@ -1,47 +1,57 @@
 #!/usr/bin/env nix-shell
-#! nix-shell -i bash -p curl gnused
+#! nix-shell -i bash --pure -p cacert curl jq nix
 
-set -eou pipefail
+set -euo pipefail
 
-latest_linux_data="$(curl -s 'https://slack.com/api/desktop.latestRelease?arch=x64&variant=deb')"
-latest_mac_data="$(curl -s 'https://slack.com/api/desktop.latestRelease?arch=universal&variant=dmg')"
-latest_mac_arm_data="$(curl -s 'https://slack.com/api/desktop.latestRelease?arch=arm64&variant=dmg')"
+cd $(readlink -e $(dirname "${BASH_SOURCE[0]}"))
 
-latest_linux_version="$(echo ${latest_linux_data} | jq -rc '.version')"
-latest_mac_version="$(echo ${latest_mac_data} | jq -rc '.version')"
-latest_mac_arm_version="$(echo ${latest_mac_arm_data} | jq -rc '.version')"
+aarch64_darwin_data=$(curl -s 'https://slack.com/api/desktop.latestRelease?arch=arm64&variant=dmg')
+x86_64_darwin_data=$(curl -s 'https://slack.com/api/desktop.latestRelease?arch=x64&variant=dmg')
+x86_64_linux_data=$(curl -s 'https://slack.com/api/desktop.latestRelease?arch=x64&variant=deb')
 
-nixpkgs="$(git rev-parse --show-toplevel)"
-slack_nix="$nixpkgs/pkgs/by-name/sl/slack/package.nix"
-nixpkgs_linux_version=$(cat "$slack_nix" | sed -n 's/.*x86_64-linux-version = \"\([0-9\.]\+\)\";.*/\1/p')
-nixpkgs_mac_version=$(cat "$slack_nix" | sed -n 's/.*x86_64-darwin-version = \"\([0-9\.]\+\)\";.*/\1/p')
-nixpkgs_mac_arm_version=$(cat "$slack_nix" | sed -n 's/.*aarch64-darwin-version = \"\([0-9\.]\+\)\";.*/\1/p')
+aarch64_darwin_version=$(jq -r .version <<< "$aarch64_darwin_data")
+x86_64_darwin_version=$(jq -r .version <<< "$x86_64_darwin_data")
+x86_64_linux_version=$(jq -r .version <<< "$x86_64_linux_data")
 
-if [[ "$nixpkgs_linux_version" == "$latest_linux_version" && \
-      "$nixpkgs_mac_version" == "$latest_mac_version" && \
-      "$nixpkgs_mac_arm_version" == "$latest_mac_version" ]]; then
-  echo "nixpkgs versions are all up to date!"
-  exit 0
-fi
+aarch64_darwin_url=$(jq -r .download_url <<< "$aarch64_darwin_data")
+x86_64_darwin_url=$(jq -r .download_url <<< "$x86_64_darwin_data")
+x86_64_linux_url=$(jq -r .download_url <<< "$x86_64_linux_data")
 
-linux_url="$(echo ${latest_linux_data} | jq -rc '.download_url')"
-mac_url="$(echo ${latest_mac_data} | jq -rc '.download_url')"
-mac_arm_url="$(echo ${latest_mac_arm_data} | jq -rc '.download_url')"
-linux_sha256=$(nix-prefetch-url ${linux_url})
-mac_sha256=$(nix-prefetch-url ${mac_url})
-mac_arm_sha256=$(nix-prefetch-url ${mac_arm_url})
+aarch64_darwin_hash=$(nix-prefetch-url "$aarch64_darwin_url")
+x86_64_darwin_hash=$(nix-prefetch-url "$x86_64_darwin_url")
+x86_64_linux_hash=$(nix-prefetch-url "$x86_64_linux_url")
 
-sed -i "s/x86_64-linux-version = \".*\"/x86_64-linux-version = \"${latest_linux_version}\"/" "$slack_nix"
-sed -i "s/x86_64-darwin-version = \".*\"/x86_64-darwin-version = \"${latest_mac_version}\"/" "$slack_nix"
-sed -i "s/aarch64-darwin-version = \".*\"/aarch64-darwin-version = \"${latest_mac_version}\"/" "$slack_nix"
-sed -i "s/x86_64-linux-sha256 = \".*\"/x86_64-linux-sha256 = \"${linux_sha256}\"/" "$slack_nix"
-sed -i "s/x86_64-darwin-sha256 = \".*\"/x86_64-darwin-sha256 = \"${mac_sha256}\"/" "$slack_nix"
-sed -i "s/aarch64-darwin-sha256 = \".*\"/aarch64-darwin-sha256 = \"${mac_arm_sha256}\"/" "$slack_nix"
+# use friendlier hashes
 
-if ! nix-build -A slack "$nixpkgs" --arg config '{ allowUnfree = true; }'; then
-  echo "The updated slack failed to build."
-  exit 1
-fi
+aarch64_darwin_hash=$(nix --extra-experimental-features nix-command hash convert --to sri --hash-algo sha256 "$aarch64_darwin_hash")
+x86_64_darwin_hash=$(nix --extra-experimental-features nix-command hash convert --to sri --hash-algo sha256 "$x86_64_darwin_hash")
+x86_64_linux_hash=$(nix --extra-experimental-features nix-command hash convert --to sri --hash-algo sha256 "$x86_64_linux_hash")
 
-echo "Successfully updated"
-echo "slack: $nixpkgs_linux_version -> $latest_linux_version"
+cat >sources.nix <<EOF
+# Generated by ./update.sh - do not update manually!
+# Last updated: $(date +%F)
+{ fetchurl }:
+{
+  aarch64-darwin = {
+    version = "$aarch64_darwin_version";
+    src = fetchurl {
+      url = "$aarch64_darwin_url";
+      hash = "$aarch64_darwin_hash";
+    };
+  };
+  x86_64-darwin = {
+    version = "$x86_64_darwin_version";
+    src = fetchurl {
+      url = "$x86_64_darwin_url";
+      hash = "$x86_64_darwin_hash";
+    };
+  };
+  x86_64-linux = {
+    version = "$x86_64_linux_version";
+    src = fetchurl {
+      url = "$x86_64_linux_url";
+      hash = "$x86_64_linux_hash";
+    };
+  };
+}
+EOF