ToolJovia
Files

Local MIME Message File Builder

Create a UTF-8 plain-text EML file with bounded attachments and encoded Unicode headers, without sending mail.

✓ Browser-local processing
Processed in this tab. Up to 100,000 characters unless this tool states a smaller limit.
Files are read locally and are not uploaded.

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How to use Local MIME Message File Builder

Prepare a reviewable local message artifact from explicit sender and recipient records. Unicode subject/display names use encoded words, body lines use declared CRLF normalization, and optional attachment bytes are encoded without rendering their content.

  1. Enter input, sender object json, recipient array json, subject, utc message date, optional local attachments.
  2. Choose the settings for local mime message file builder, then run the tool.
  3. Review the result and any limitations before copying or downloading it.

Good to know

  • Simple ASCII dot-atom addresses up to 60 characters, 20 recipients, 500 subject characters, 100,000 body characters, 5 attachments totaling 2 MiB and a 4 MiB EML output. Attachment names use at most 50 UTF-8 bytes.
  • No SMTP, sending, sender authentication, HTML body, Bcc, internationalized addresses, nested messages or promised client-specific draft import. Header controls and path-bearing attachment names are refused. Body line endings are normalized to CRLF; attachment bytes are preserved.
  • Processing is local. Output is limited to 1,000,000 text characters unless a stricter file limit is stated.

Common questions

Does downloading this file send a message or open an authenticated draft?

No. It only creates a local message file. Import behavior depends on your mail application, and sending requires a separate deliberate action in that application.

Is this input sent to a server?

No. The application processes this input inside your browser tab and does not save it to persistent storage.

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