diff --git a/app/.dockerignore b/app/.dockerignore
index f06235c..69e11c9 100644
--- a/app/.dockerignore
+++ b/app/.dockerignore
@@ -1,2 +1,4 @@
 node_modules
 dist
+.env
+.env.*
diff --git a/app/Dockerfile b/app/Dockerfile
index 723aacb..a789219 100644
--- a/app/Dockerfile
+++ b/app/Dockerfile
@@ -1,13 +1,15 @@
 FROM node:22-alpine
 
 WORKDIR /app
+ENV NODE_ENV=production
 
 COPY package.json package-lock.json ./
 RUN npm ci
 
 COPY tsconfig.json ./
 COPY public ./public
-# Runtime mappers read JSON files from src/mappings, so they must be copied into the image.
 COPY src ./src
 
-CMD ["npm", "run", "start"]
+RUN npm run build && npm prune --omit=dev
+
+CMD ["node", "dist/index.js"]
diff --git a/app/package-lock.json b/app/package-lock.json
index 1d81405..b1b654b 100644
--- a/app/package-lock.json
+++ b/app/package-lock.json
@@ -6,11 +6,13 @@
     "": {
       "name": "mqtt-worker",
       "dependencies": {
-        "@types/node": "^25.9.1",
         "mqtt": "^5.15.1",
-        "tsx": "^4.22.4",
-        "typescript": "^6.0.3",
         "ws": "^8.21.0"
+      },
+      "devDependencies": {
+        "@types/node": "^25.9.1",
+        "tsx": "^4.22.4",
+        "typescript": "^6.0.3"
       }
     },
     "node_modules/@babel/runtime": {
@@ -29,6 +31,7 @@
       "cpu": [
         "ppc64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -45,6 +48,7 @@
       "cpu": [
         "arm"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -61,6 +65,7 @@
       "cpu": [
         "arm64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -77,6 +82,7 @@
       "cpu": [
         "x64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -93,6 +99,7 @@
       "cpu": [
         "arm64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -109,6 +116,7 @@
       "cpu": [
         "x64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -125,6 +133,7 @@
       "cpu": [
         "arm64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -141,6 +150,7 @@
       "cpu": [
         "x64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -157,6 +167,7 @@
       "cpu": [
         "arm"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -173,6 +184,7 @@
       "cpu": [
         "arm64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -189,6 +201,7 @@
       "cpu": [
         "ia32"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -205,6 +218,7 @@
       "cpu": [
         "loong64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -221,6 +235,7 @@
       "cpu": [
         "mips64el"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -237,6 +252,7 @@
       "cpu": [
         "ppc64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -253,6 +269,7 @@
       "cpu": [
         "riscv64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -269,6 +286,7 @@
       "cpu": [
         "s390x"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -285,6 +303,7 @@
       "cpu": [
         "x64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -301,6 +320,7 @@
       "cpu": [
         "arm64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -317,6 +337,7 @@
       "cpu": [
         "x64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -333,6 +354,7 @@
       "cpu": [
         "arm64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -349,6 +371,7 @@
       "cpu": [
         "x64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -365,6 +388,7 @@
       "cpu": [
         "arm64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -381,6 +405,7 @@
       "cpu": [
         "x64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -397,6 +422,7 @@
       "cpu": [
         "arm64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -413,6 +439,7 @@
       "cpu": [
         "ia32"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -429,6 +456,7 @@
       "cpu": [
         "x64"
       ],
+      "dev": true,
       "license": "MIT",
       "optional": true,
       "os": [
@@ -607,6 +635,7 @@
       "version": "0.28.0",
       "resolved": "https://registry.npmjs.org/esbuild/-/esbuild-0.28.0.tgz",
       "integrity": "sha512-sNR9MHpXSUV/XB4zmsFKN+QgVG82Cc7+/aaxJ8Adi8hyOac+EXptIp45QBPaVyX3N70664wRbTcLTOemCAnyqw==",
+      "dev": true,
       "hasInstallScript": true,
       "license": "MIT",
       "bin": {
@@ -679,6 +708,7 @@
       "version": "2.3.3",
       "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.3.tgz",
       "integrity": "sha512-5xoDfX+fL7faATnagmWPpbFtwh/R77WmMMqqHGS65C3vvB0YHrgF+B1YmZ3441tMj5n63k0212XNoJwzlhffQw==",
+      "dev": true,
       "hasInstallScript": true,
       "license": "MIT",
       "optional": true,
@@ -923,6 +953,7 @@
       "version": "4.22.4",
       "resolved": "https://registry.npmjs.org/tsx/-/tsx-4.22.4.tgz",
       "integrity": "sha512-X8EX+XV4QR5xCsrgxaED954zTDfY8KqlDtskKEL0cHhyS/P8b4IFOvGDQpsC9Q1XnLq915wEfwwY/zzskCtmhg==",
+      "dev": true,
       "license": "MIT",
       "dependencies": {
         "esbuild": "~0.28.0"
@@ -947,6 +978,7 @@
       "version": "6.0.3",
       "resolved": "https://registry.npmjs.org/typescript/-/typescript-6.0.3.tgz",
       "integrity": "sha512-y2TvuxSZPDyQakkFRPZHKFm+KKVqIisdg9/CZwm9ftvKXLP8NRWj38/ODjNbr43SsoXqNuAisEf1GdCxqWcdBw==",
+      "dev": true,
       "license": "Apache-2.0",
       "bin": {
         "tsc": "bin/tsc",
diff --git a/app/package.json b/app/package.json
index 3399ecd..6e595dd 100644
--- a/app/package.json
+++ b/app/package.json
@@ -5,13 +5,15 @@
   "scripts": {
     "dev": "tsx watch src/index.ts",
     "build": "tsc",
-    "start": "tsx src/index.ts"
+    "start": "node dist/index.js"
   },
   "dependencies": {
-    "@types/node": "^25.9.1",
     "mqtt": "^5.15.1",
-    "tsx": "^4.22.4",
-    "typescript": "^6.0.3",
     "ws": "^8.21.0"
+  },
+  "devDependencies": {
+    "@types/node": "^25.9.1",
+    "tsx": "^4.22.4",
+    "typescript": "^6.0.3"
   }
 }
diff --git a/app/src/handlers/edge5-modbus-v2.ts b/app/src/handlers/edge5-modbus-v2.ts
index ee6d67a..e5bfaed 100644
--- a/app/src/handlers/edge5-modbus-v2.ts
+++ b/app/src/handlers/edge5-modbus-v2.ts
@@ -7,20 +7,9 @@ export const TOPIC = 'data/edge5/modbus/v2'
 const mapper = createMetricMapper({
   filePath: process.env.EDGE5_MODBUS_V2_MAPPING_FILE as string,
 })
-const REGISTER_COUNT = mapper.tagCount
 
 function parseValues(payload: Buffer): number[] {
-  const value = JSON.parse(payload.toString('utf8')) as unknown
-
-  if (
-    Array.isArray(value) &&
-    value.length === REGISTER_COUNT &&
-    value.every((item) => typeof item === 'number' && Number.isFinite(item))
-  ) {
-    return value
-  }
-
-  throw new Error(`Expected JSON number[${REGISTER_COUNT}]`)
+  return JSON.parse(payload.toString('utf8')) as number[]
 }
 
 async function postMetrics(metrics: MappedMetric[]): Promise<void> {
diff --git a/app/src/handlers/edge5-modbus.ts b/app/src/handlers/edge5-modbus.ts
index 5416393..7b6b25f 100644
--- a/app/src/handlers/edge5-modbus.ts
+++ b/app/src/handlers/edge5-modbus.ts
@@ -4,7 +4,6 @@ import type { TopicHandler } from '../types.js'
 export const TOPIC = 'data/edge5/modbus/v1'
 
 const EDGE = 'edge5'
-const REGISTER_COUNT = 125
 
 type Edge5ModbusMetric = {
   edge: string
@@ -14,23 +13,7 @@ type Edge5ModbusMetric = {
 }
 
 function parseValues(payload: Buffer): number[] {
-  let value: unknown
-
-  try {
-    value = JSON.parse(payload.toString('utf8')) as unknown
-  } catch {
-    throw new Error(`Expected JSON number[${REGISTER_COUNT}]`)
-  }
-
-  if (
-    Array.isArray(value) &&
-    value.length === REGISTER_COUNT &&
-    value.every((item) => typeof item === 'number' && Number.isFinite(item))
-  ) {
-    return value
-  }
-
-  throw new Error(`Expected JSON number[${REGISTER_COUNT}]`)
+  return JSON.parse(payload.toString('utf8')) as number[]
 }
 
 function toMetrics(values: number[], timestamp: number): Edge5ModbusMetric[] {
@@ -47,12 +30,7 @@ async function postMetrics(metrics: Edge5ModbusMetric[]): Promise<void> {
 
   if (!response.ok) {
     const text = await response.text()
-    console.error('edge5.modbus.post_error', {
-      status: response.status,
-      statusText: response.statusText,
-      body: text.slice(0, 500),
-    })
-    return
+    throw new Error(text)
   }
 
   console.log('edge5.modbus.posted', { count: metrics.length })
@@ -61,15 +39,7 @@ async function postMetrics(metrics: Edge5ModbusMetric[]): Promise<void> {
 export const handleEdge5Modbus: TopicHandler = async (topic, payload) => {
   console.log('edge5.modbus.received', { topic, bytes: payload.length })
 
-  let values: number[]
-
-  try {
-    values = parseValues(payload)
-  } catch (err) {
-    console.warn('edge5.modbus.invalid_payload', { topic, err })
-    return
-  }
-
+  const values = parseValues(payload)
   const metrics = toMetrics(values, Date.now())
   await postMetrics(metrics)
 }
diff --git a/app/src/helpers/parse.ts b/app/src/helpers/parse.ts
index b132076..27b05ee 100644
--- a/app/src/helpers/parse.ts
+++ b/app/src/helpers/parse.ts
@@ -7,14 +7,6 @@ export function parseJson<T = unknown>(payload: Buffer): T {
   return JSON.parse(text) as T
 }
 
-export function parseJsonArray(payload: Buffer): unknown[] {
-  const value = parseJson(payload)
-  if (!Array.isArray(value)) {
-    throw new Error('Expected JSON array')
-  }
-  return value
-}
-
 export function decodeBase64(payload: Buffer): Buffer {
   return Buffer.from(payload.toString('utf8'), 'base64')
 }
diff --git a/app/src/helpers/validate.ts b/app/src/helpers/validate.ts
deleted file mode 100644
index f37fffb..0000000
--- a/app/src/helpers/validate.ts
+++ /dev/null
@@ -1,39 +0,0 @@
-const EXPECTED_CHUNK_LENGTH = 125
-
-export function isNonEmptyString(value: unknown): value is string {
-  return typeof value === 'string' && value.length > 0
-}
-
-export function isFiniteNumber(value: unknown): value is number {
-  return typeof value === 'number' && Number.isFinite(value)
-}
-
-export function isArrayOfLength(
-  value: unknown,
-  length: number,
-): value is unknown[] {
-  return Array.isArray(value) && value.length === length
-}
-
-export function isArrayOfLength125(value: unknown): value is unknown[] {
-  return isArrayOfLength(value, EXPECTED_CHUNK_LENGTH)
-}
-
-export function isArrayOfChunks125(
-  value: unknown,
-): value is unknown[][] {
-  if (!Array.isArray(value)) {
-    return false
-  }
-  return value.every((chunk) => isArrayOfLength125(chunk))
-}
-
-export function assertValid<T>(
-  value: unknown,
-  guard: (v: unknown) => v is T,
-  label: string,
-): asserts value is T {
-  if (!guard(value)) {
-    throw new Error(`Invalid payload: ${label}`)
-  }
-}
diff --git a/app/src/mapping.ts b/app/src/mapping.ts
index 929f98c..cbbb8ca 100644
--- a/app/src/mapping.ts
+++ b/app/src/mapping.ts
@@ -14,7 +14,6 @@ type MappingConfig = {
 
 export type MetricMapper = {
   edge: string
-  tagCount: number
   mapValues: (values: number[], timestamp: number) => MappedMetric[]
 }
 
@@ -34,7 +33,6 @@ export function createMetricMapper(options: MetricMapperOptions): MetricMapper {
 
   return {
     edge: config.edge,
-    tagCount: config.tags.length,
     mapValues: (values, timestamp) =>
       values.map((value, index) => ({
         edge: config.edge,
diff --git a/app/tsconfig.json b/app/tsconfig.json
index a3f07a9..02b90f0 100644
--- a/app/tsconfig.json
+++ b/app/tsconfig.json
@@ -7,8 +7,7 @@
     "esModuleInterop": true,
     "skipLibCheck": true,
     "outDir": "dist",
-    "rootDir": "src",
-    "noEmit": true
+    "rootDir": "src"
   },
   "include": ["src/**/*.ts"]
 }