Sending API, SMTP & developer experience — found from sitemap — Lettermint

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Facts read from this source

• Smtp host Report an error

  “Host smtp.lettermint.co”

• Smtp default port Report an error

  “Port 587 (see available ports )”

• Smtp auth mechanisms Report an error

  “Authentication PLAIN and LOGIN”

• Smtp username Report an error

  “Username lettermint”

• Smtp password is project API token Report an error

  “Password Your Lettermint Project API token”

• Smtp requires project enablement Report an error

  “First, enable SMTP for the project you want to use. You can find this setting under your Projects.”

• Smtp supported ports Report an error

  “Port Security Notes 25 STARTTLS (optional encryption upgrade) Not recommended, blocked by many ISPs and cloud providers 587 STARTTLS (encryption upgrade) Recommended as alternative if Implicit TLS is not supported 465 Implicit TLS (SMTPS, encrypted from connection) Recommended for best security 2525 STARTTLS (encryption upgrade) Alternative to port 25 2465 Implicit TLS (SMTPS, encrypted from connection) Alternative to port 465 2587 STARTTLS (encryption upgrade) Alternative to port 587”

• Smtp auth always required Report an error

  “Authentication is always required when using Lettermint's SMTP service”

• Smtp tls always required Report an error

  “Always use TLS encryption (either STARTTLS or Implicit TLS) to protect your credentials”

• Smtp ip allowlist support Report an error

  “If the Project API token has an IP allowlist, SMTP connections must originate from an allowed IP address or CIDR range.”

• Smtp smtp smuggling protection Report an error

  “If a line ends with a bare LF (\n), Lettermint rejects the message with a 451 reply and closes the connection. Lettermint does not repair these line endings.”

• Header sandbox result Report an error

  “X-Lettermint-Sandbox-Result Select the simulated result for an email sent through a Sandbox project”

• Header scheduling Report an error

  “Growth and Pro teams can schedule an authenticated outbound SMTP message with X-LM-Scheduled-At.”

• Header route Report an error

  “You can control email routing by including the X-Lettermint-Route header in your SMTP messages. This header accepts a route's slug to specify which route should handle the email.”

• Header preserve message id Report an error

  “Lettermint replaces submitted Message-ID fields by default. If your application stores its own RFC Message-ID for reply threading, opt in to preserving it for a single email”

• Header tls override Report an error

  “X-LM-Override-TLS Override the selected route's TLS delivery policy for one email”

• Header tag Report an error

  “The singular tag can have a maximum of 255 characters.”

• Header tags limit Report an error

  “The combined limit is 20 tags. The singular tag uses one place in this limit.”

• Header tags size limits Report an error

  “Each header value can have a maximum of 900 ASCII bytes. A name can have 1 to 32 ASCII letters, digits, underscores, or hyphens. A value can have 1 to 64 ASCII letters, digits, underscores, or hyphens.”

• Header metadata Report an error

  “Metadata headers use a prefix pattern where anything after X-LM-Metadata- becomes the metadata key.”

• Smtp no fixed rate limit Report an error

  “Send endpoints are not throttled by a fixed per-minute API rate limit, but plan quota, spend limits, account verification, reputation, and abuse controls still apply.”

• Smtp control headers not delivered Report an error

  “Lettermint consumes all these control headers before delivery. Recipients do not receive them.”

• Smtp symfony mailer compat Report an error

  “You can also use X-Tag for compatibility with Symfony Mailer. X-LM-Tag takes precedence when both headers are present.”

• Cli available Report an error

  “Sending API Team API MCP server CLI”

• Response codes documented Report an error

  “A 4xx code is a temporary failure, so retry later. A 5xx code is permanent, so fix the cause before you send the message again.”

• Testing tool swaks Report an error

  “# Install swaks (SMTP testing tool)”

Scores citing this record

• The Agency Lead Sending API, SMTP & developer experience
• The Agency Lead Message data, retention & security
• The Data Protection Officer Sending API, SMTP & developer experience
• The Data Protection Officer Message data, retention & security
• The Data Protection Officer Reliability, accounts & support
• The Shop Operator Sending API, SMTP & developer experience
• The Shop Operator Message data, retention & security
• The Shop Operator Reliability, accounts & support
• The Platform Engineer Sending API, SMTP & developer experience
• The Platform Engineer Message data, retention & security
• The SaaS Developer Sending API, SMTP & developer experience
• The SaaS Developer Message data, retention & security
• The SaaS Developer Reliability, accounts & support
• The Skeptic Sending API, SMTP & developer experience
• The Skeptic Message data, retention & security