diff --git a/.npmignore b/.npmignore
new file mode 100644
index 0000000..7846446
--- /dev/null
+++ b/.npmignore
@@ -0,0 +1,58 @@
+# === Mirrors .gitignore — same deny list applies when packing for npm,
+#     kept verbatim so npm pack doesn't fall back to .gitignore silently
+#     (warning: gitignore-fallback). ===
+node_modules/
+package-lock.json
+*.tgz
+*.log
+npm-debug.log*
+.env
+.env.*
+.DS_Store
+
+# === Memory + IDE state — NEVER ships (838 MB of .repo-mem alone) ===
+.repo-mem/
+.codex
+.codex/
+.claude/
+.agents/
+CLAUDE.md
+CLAUDE.local.md
+
+# === Repo-level dev tooling ===
+tools/
+docker/
+docker-compose.yml
+Dockerfile
+.dockerignore
+.gitea/
+eslint.config.js
+jest.config.js
+scripts/
+test/
+
+# === Repo-level docs not needed by Node-RED consumers ===
+wiki/
+CONTRACTS.md
+.gitmodules
+
+# === Per-submodule dev-only trees ===
+# `npm pack` at the parent walks the file tree directly and IGNORES each
+# submodule's own .npmignore. So we mirror the per-submodule deny lists
+# here explicitly, otherwise the root tarball still bundles every test
+# tree, wiki, simulation harness, screen recording, etc. — that's how
+# the root pack was 175 MB before this file existed.
+nodes/*/test/
+nodes/*/wiki/
+nodes/*/simulations/
+nodes/*/tools/
+nodes/*/scripts/
+nodes/*/CLAUDE.md
+nodes/*/CLAUDE.local.md
+nodes/*/.claude/
+nodes/*/.codex/
+nodes/*/.git
+nodes/*/.gitignore
+nodes/*/.npmignore
+nodes/*/.eslintrc*
+nodes/*/eslint.config.js