diff --git a/tools/api-diff.nu b/tools/api-diff.nu
new file mode 100755
index 0000000000..b6f8b0ce62
--- /dev/null
+++ b/tools/api-diff.nu
@@ -0,0 +1,57 @@
+#! /usr/bin/env nu
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# Copyright Oxide Computer Company
+
+def genForCommit [commit] {
+  let tmpDir = $"/tmp/api-diff/($commit)"
+  rm -rf $tmpDir
+  mkdir $tmpDir
+  npm run --silent --prefix ../oxide.ts gen-from $commit $tmpDir
+  npx prettier --write --log-level error $tmpDir
+}
+
+if (which gh | is-empty) {
+  error make {msg: 'gh is not installed'}
+}
+
+let rowTemplate =  '{{range .}}{{tablerow .number .title .author.name (timeago .updatedAt)}}{{end}}'
+
+def promptForPr [] {
+  gh pr list -R oxidecomputer/omicron -L 100 --json number,title,updatedAt,author -t $rowTemplate | 
+    fzf --height 25% --reverse |
+    cut -f1 -d ' '
+}
+
+def main [prNum?: int] {
+  let prNum = if ($prNum == null) {
+    gh pr list -R oxidecomputer/omicron -L 100 --json number,title,updatedAt,author -t $rowTemplate | 
+      fzf --height 25% --reverse |
+      cut -f1 -d ' '
+  } else {
+    $prNum
+  }
+
+  let query = $"query={ 
+    repository\(owner: \"oxidecomputer\", name: \"omicron\") { 
+      pullRequest\(number: ($prNum)) { 
+        baseRefOid
+        headRefOid
+      }
+    }
+  }"
+
+  let pr = (gh api graphql -f $query | from json | get data.repository.pullRequest)
+
+  let base = $pr | get baseRefOid
+  genForCommit $base
+
+  let head = $pr | get headRefOid
+  genForCommit $head
+
+  # git difftool is a trick to diff with whatever you have git set to use
+  git --no-pager difftool $"/tmp/api-diff/($base)/Api.ts" $"/tmp/api-diff/($head)/Api.ts"
+}
diff --git a/tools/api-diff.sh b/tools/api-diff.sh
new file mode 100755
index 0000000000..24584b5158
--- /dev/null
+++ b/tools/api-diff.sh
@@ -0,0 +1,51 @@
+#! /usr/bin/env bash
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# Copyright Oxide Computer Company
+
+function genForCommit() {
+  COMMIT=$1
+  TMP_DIR="/tmp/api-diff/$COMMIT"
+  rm -rf $TMP_DIR
+  mkdir -p $TMP_DIR
+  npm run --silent --prefix ../oxide.ts gen-from $COMMIT $TMP_DIR
+  npx prettier --write --log-level error $TMP_DIR
+}
+
+if ! command -v gh &> /dev/null; then
+  echo "Error: gh is not installed." >&2
+  exit 1
+fi
+
+PR_NUM=$(
+  gh pr list -R oxidecomputer/omicron --limit 100 --json number,title,updatedAt,author \
+    --template '{{range .}}{{tablerow .number .title .author.name (timeago .updatedAt)}}{{end}}' |
+   fzf --height 25% --reverse |
+   cut -f1 -d ' '
+)
+
+if ! [[ "$PR_NUM" =~ ^[0-9]+$ ]]; then
+  echo "Error picking PR. Expected number, got $PR_NUM" >&2
+  exit 1
+fi
+
+PR_JSON=$(gh api graphql -f query="{ 
+  repository(owner: \"oxidecomputer\", name: \"omicron\") { 
+    pullRequest(number: $PR_NUM) { 
+      baseRefOid
+      headRefOid
+    }
+  }
+}" | jq -r '.data.repository.pullRequest')
+
+BASE=$(echo $PR_JSON | jq -r '.baseRefOid')
+genForCommit $BASE
+
+HEAD=$(echo $PR_JSON | jq -r '.headRefOid')
+genForCommit $HEAD
+
+# git difftool is a trick to diff with whatever you have git set to use
+git --no-pager difftool "/tmp/api-diff/$BASE/Api.ts" "/tmp/api-diff/$HEAD/Api.ts" || true