diff --git a/Makefile b/Makefile
index ebe9f18..1b2192b 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,7 @@ COMMIT ?= $(shell git rev-parse --short HEAD || echo unknown)
 BUILDTIME ?= $(shell date +%s)
 
 UPDATER ?= off
-LDFLAGS := -X main.version=$(VERSION) -X main.commit=$(COMMIT) -X main.cssVersion=$(CSSVERSION) -X main.buildTimeUnix=$(BUILDTIME)
+LDFLAGS := -X main.version=$(VERSION) -X main.commit=$(COMMIT) -X main.cssVersion=$(CSSVERSION) -X main.buildTimeUnix=$(BUILDTIME) $(if $(BUILTBY),-X 'main.builtBy=$(BUILTBY)',)
 ifeq ($(UPDATER), on)
 	LDFLAGS := $(LDFLAGS) -X main.updater=binary
 else ifneq ($(UPDATER), off)
@@ -75,14 +75,23 @@ else
 	RACEDETECTOR :=
 endif
 
+ifeq (, $(shell which esbuild))
+	ESBUILDINSTALL := go install github.com/evanw/esbuild/cmd/esbuild@latest
+else
+	ESBUILDINSTALL :=
+endif
+
+ifeq ($(GOESBUILD), on)
+	NPMIGNOREOPTIONAL := --no-optional
+	NPMOPTS := $(NPMIGNOREOPTIONAL); $(ESBUILDINSTALL)
+else
+	NPMOPTS :=
+endif
+
+
 npm:
 	$(info installing npm dependencies)
-	npm install
-	@if [ "$(GOESBUILD)" = "off" ]; then\
-		npm install esbuild;\
-	else\
-		go install github.com/evanw/esbuild/cmd/esbuild@latest;\
-	fi
+	npm install $(NPMOPTS)
 
 configuration:
 	$(info Fixing config-base)
diff --git a/package-lock.json b/package-lock.json
index c1cd61f..0d2b0cf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -15,7 +15,6 @@
         "any-date-parser": "^1.5.4",
         "browserslist": "^4.21.7",
         "cheerio": "^1.0.0-rc.12",
-        "esbuild": "^0.18.6",
         "fs-cheerio": "^3.0.0",
         "inline-source": "^8.0.2",
         "jsdom": "^22.1.0",
@@ -32,6 +31,9 @@
       },
       "devDependencies": {
         "live-server": "^1.2.2"
+      },
+      "optionalDependencies": {
+        "esbuild": "^0.18.6"
       }
     },
     "node_modules/@alloc/quick-lru": {
@@ -1651,6 +1653,7 @@
       "resolved": "https://registry.npmjs.org/esbuild/-/esbuild-0.18.6.tgz",
       "integrity": "sha512-5QgxWaAhU/tPBpvkxUmnFv2YINHuZzjbk0LeUUnC2i3aJHjfi5yR49lgKgF7cb98bclOp/kans8M5TGbGFfJlQ==",
       "hasInstallScript": true,
+      "optional": true,
       "bin": {
         "esbuild": "bin/esbuild"
       },
@@ -7899,6 +7902,7 @@
       "version": "0.18.6",
       "resolved": "https://registry.npmjs.org/esbuild/-/esbuild-0.18.6.tgz",
       "integrity": "sha512-5QgxWaAhU/tPBpvkxUmnFv2YINHuZzjbk0LeUUnC2i3aJHjfi5yR49lgKgF7cb98bclOp/kans8M5TGbGFfJlQ==",
+      "optional": true,
       "requires": {
         "@esbuild/android-arm": "0.18.6",
         "@esbuild/android-arm64": "0.18.6",
diff --git a/package.json b/package.json
index e154b97..7b7f95a 100644
--- a/package.json
+++ b/package.json
@@ -23,7 +23,6 @@
     "any-date-parser": "^1.5.4",
     "browserslist": "^4.21.7",
     "cheerio": "^1.0.0-rc.12",
-    "esbuild": "^0.18.6",
     "fs-cheerio": "^3.0.0",
     "inline-source": "^8.0.2",
     "jsdom": "^22.1.0",
@@ -40,5 +39,8 @@
   },
   "devDependencies": {
     "live-server": "^1.2.2"
+  },
+  "optionalDependencies": {
+    "esbuild": "^0.18.6"
   }
 }
diff --git a/scripts/compile_mjml.py b/scripts/compile_mjml.py
index f7510bf..8341c5e 100755
--- a/scripts/compile_mjml.py
+++ b/scripts/compile_mjml.py
@@ -13,8 +13,8 @@ args = parser.parse_args()
 def runcmd(cmd):
     if os.name == "nt":
         return subprocess.check_output(cmd, shell=True)
-    proc = subprocess.Popen(cmd.split(), stdout=subprocess.PIPE)
-    return proc.communicate()
+    with subprocess.Popen(cmd.split(), stdout=subprocess.PIPE) as proc:
+        return proc.communicate()
 
 def compile(mjml: Path):
     fname = mjml.with_suffix(".html")