Mail, WhatsApp, and file storage

Mail

Build the mailer from configuration in your application code:

mailer, err := mail.New(cfg.MailOptions())

message := mail.NewMessage().
    To(user.Email).
    Subject("Welcome!").
    HTMLTemplate(templates, "welcome.html", map[string]any{"Name": user.Name}).
    Text("Welcome to the app.")

err = mailer.Send(ctx, message)

MAIL_DRIVER=log (the default) renders the complete MIME message into your structured logs — no SMTP server needed in development. MAIL_DRIVER=smtp sends through MAIL_HOST/MAIL_PORT with MAIL_ENCRYPTION set to starttls (587, default), tls (465), or none (25), authenticating when MAIL_USERNAME is set. For a local inbox UI, run docker compose --profile mail up and point MAIL_HOST=localhost, MAIL_PORT=1025, MAIL_ENCRYPTION=none at Mailpit (web UI on :8025).

Scaffold a typed mailable plus its HTML template with gin-kit generate mail <Name> (runtime project type only).

Runtime projects can send approved WhatsApp Business templates directly with Meta’s official Cloud API. WHATSAPP_DRIVER=log is safe for local development: it logs redacted delivery metadata but never recipient numbers, codes, template parameters, or access tokens. Set WHATSAPP_DRIVER=cloud and configure the Meta access token, phone number ID, and Graph API version for delivery.

See WhatsApp Cloud API for configuration, the authentication-code helper, generic template components, and delivery safety.

File storage

runtime/storage puts local and S3-compatible file storage behind one interface:

disk, err := storage.New(cfg.StorageOptions())

err = disk.Put(ctx, "avatars/user-1.png", file, storage.WithContentType("image/png"))
reader, err := disk.Get(ctx, "avatars/user-1.png")
url, err := disk.URL(ctx, "avatars/user-1.png")

// In a handler: store a multipart upload directly.
size, err := storage.SaveUpload(c, disk, "avatar", "avatars/"+userID+".png")

STORAGE_DRIVER=local (default) confines every path to STORAGE_LOCAL_ROOT — traversal attempts like ../../etc/passwd are rejected, and writes are atomic. STORAGE_DRIVER=s3 works with any S3-compatible store (AWS S3, MinIO, Cloudflare R2, DigitalOcean Spaces) through S3_ENDPOINT, S3_BUCKET, S3_ACCESS_KEY/S3_SECRET_KEY; URL() returns S3_PUBLIC_BASE_URL joins when configured, presigned URLs (S3_PRESIGN_TTL) otherwise. For local object storage, docker compose --profile storage up starts MinIO (S3_ENDPOINT=localhost:9000, S3_USE_PATH_STYLE=true, S3_USE_SSL=false, credentials minioadmin).