feat: add email worker using Cloudflare Email Sending API

AGENTS.md

@@ -14,6 +14,7 @@ This is a **TypeScript monorepo** for applications on the Tempo blockchain appli
 | `apps/tokenlist` | Token registry API |
 | `apps/contract-verification` | Smart contract verification |
 | `apps/og` | OpenGraph image generation |
+| `apps/email` | Transactional email sending via Cloudflare Email Service |
 
 ## Commands
 

apps/email/.env.example

@@ -0,0 +1,3 @@
+# No environment variables required for basic email sending.
+# The SEND_EMAIL binding is configured in wrangler.json.
+# To restrict senders/recipients, update the send_email binding in wrangler.json.

apps/email/package.json

@@ -0,0 +1,25 @@
+{
+	"name": "email",
+	"type": "module",
+	"private": true,
+	"scripts": {
+		"dev": "wrangler dev",
+		"build": "echo 'No build step needed for Cloudflare Worker'",
+		"deploy": "wrangler deploy",
+		"check": "pnpm check:biome && pnpm check:types",
+		"check:biome": "biome check --write --unsafe",
+		"check:types": "tsgo --project tsconfig.json --noEmit",
+		"gen:types": "wrangler types --env-interface='CloudflareBindings' --env-file='.env.example'",
+		"postinstall": "pnpm gen:types"
+	},
+	"dependencies": {
+		"@hono/zod-validator": "catalog:",
+		"hono": "catalog:",
+		"zod": "catalog:"
+	},
+	"devDependencies": {
+		"@cloudflare/workers-types": "catalog:",
+		"@types/node": "catalog:",
+		"wrangler": "catalog:"
+	}
+}

apps/email/src/index.ts

@@ -0,0 +1,36 @@
+import { zValidator } from '@hono/zod-validator'
+import { Hono } from 'hono'
+import { cors } from 'hono/cors'
+import * as z from 'zod'
+
+const emailAddress = z.object({
+	email: z.string().email(),
+	name: z.string(),
+})
+
+const sendSchema = z.object({
+	from: z.union([z.string().email(), emailAddress]),
+	to: z.union([z.string().email(), z.array(z.string().email()).min(1)]),
+	subject: z.string().min(1),
+	replyTo: z.union([z.string().email(), emailAddress]).optional(),
+	cc: z.union([z.string().email(), z.array(z.string().email())]).optional(),
+	bcc: z.union([z.string().email(), z.array(z.string().email())]).optional(),
+	text: z.string().optional(),
+	html: z.string().optional(),
+})
+
+const app = new Hono<{ Bindings: CloudflareBindings }>()
+
+app.use('*', cors())
+
+app.get('/health', (c) => c.text('ok'))
+
+app.post('/send', zValidator('json', sendSchema), async (c) => {
+	const body = c.req.valid('json')
+
+	await c.env.SEND_EMAIL.send(body)
+
+	return c.json({ success: true })
+})
+
+export default app

apps/email/tsconfig.json

@@ -0,0 +1,29 @@
+{
+	"compilerOptions": {
+		"target": "ES2024",
+		"module": "ESNext",
+		"lib": ["ES2024"],
+		"types": ["@cloudflare/workers-types", "node"],
+		"moduleResolution": "bundler",
+		"noEmit": true,
+		"strict": true,
+		"skipLibCheck": true,
+		"esModuleInterop": true,
+		"resolveJsonModule": true,
+		"allowSyntheticDefaultImports": true,
+		"forceConsistentCasingInFileNames": true,
+		"allowJs": true,
+		"checkJs": false,
+		"allowImportingTsExtensions": true,
+		"resolvePackageJsonImports": true,
+		"resolvePackageJsonExports": true,
+		"useUnknownInCatchVariables": true,
+		"noUncheckedIndexedAccess": true,
+		"paths": {
+			"#*": ["./src/*"]
+		}
+	},
+	"files": ["worker-configuration.d.ts"],
+	"include": ["src/**/*.ts"],
+	"exclude": ["node_modules", "dist"]
+}

apps/email/wrangler.json

@@ -0,0 +1,23 @@
+{
+	"$schema": "./node_modules/wrangler/config-schema.json",
+	"name": "email",
+	"main": "src/index.ts",
+	"compatibility_date": "2025-12-17",
+	"compatibility_flags": ["nodejs_compat"],
+	"workers_dev": true,
+	"preview_urls": true,
+	"send_email": [
+		{
+			"name": "SEND_EMAIL"
+		}
+	],
+	"observability": {
+		"enabled": true,
+		"logs": {
+			"enabled": true,
+			"persist": true,
+			"head_sampling_rate": 1,
+			"invocation_logs": true
+		}
+	}
+}