Multipart Form Body Workbench
Build ordered text/file-like parts or inspect a bounded Base64 multipart body.
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How to use Multipart Form Body Workbench
Build ordered text/file-like parts or inspect a bounded Base64 multipart body. The builder produces actual UTF8 multipart bytes, a Content-Type value and a Base64 representation. Inspect separates exact byte boundaries and preserves repeated fields, part headers and binary bodies as Base64.
- Provide json parts or base64 multipart bytes, boundary.
- Choose the supported mode and run the tool. Review its assumptions and any reported errors.
- Copy the result or download a separate output; reset to clear the current form.
Good to know
- 64KiB body,100 parts,10,000 header bytes per part. Boundary is8–70 ASCII letters/digits/_/-. Builder values are text strings.
- No uploads, requests, automatic file opening, nested multipart or epilogue handling. Values starting any line with the selected boundary marker are refused. A filename does not establish a trusted content type.
- Inputs are processed on this device and are not automatically saved or uploaded.
Common questions
Can I inspect binary part content?
Yes. Inspect accepts Base64 for the entire body and reports each part as Base64, with text only when strict UTF8 decoding succeeds. Builder creates UTF8 text part values.
Does this change my original input?
No. The tool returns a separate result. Review that output before using it in another application.
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