multipart-decoder · PyPI | DevOps & Frappe Technical Specs

The Problem

Lambda functions and microservices often need to parse file uploads — but every existing solution pulls in framework dependencies that balloon cold-start times.

Qualitative Outcome

A lightweight, open-source tool published to PyPI — letting Lambda functions and microservices parse complex form data without the bloat.

What changed for the business

A zero-dependency Python library that parses multipart form data fast — keeping serverless functions lean and cheap.

How it was built

A pure Python multipart/form-data parser with streaming byte handling, zero external dependencies, and PyPI packaging via GitHub Actions and twine.

Architecture Snapshot

Binary PayloadsRaw Multipart Byte Stream

→

Streaming ParserZero-Dependency Python Chunk Parse

→

Structured DictionaryClean parsed key-value variables

What I Built

Authored a complete multipart parser in pure Python — no dependencies, no framework required.
Built PyPI packaging and publishing workflows using twine and GitHub Actions CI.
Wrote unit tests covering nested boundaries, multi-file uploads, and mixed text inputs.
Implemented streaming byte processing to handle large file uploads without excessive RAM usage.

How It Works

Parsing file uploads inside a Lambda function shouldn’t mean pulling in Flask or FastAPI just to read a multipart boundary. This package does one thing: decodes multipart/form-data payloads from raw HTTP streams — with no dependencies, fast cold starts, and a simple API.

Why It’s Designed This Way

Streaming — Bytes are processed as they arrive. Large files don’t load into RAM. Memory usage stays flat even at scale.
Zero Dependencies — One import. No version conflicts. No transitive vulnerabilities.
Drop-in Simple — Works directly inside an AWS Lambda handler or any lightweight Flask/FastAPI service.

Building something similar?

I'd love to hear about what you're working on.

Start a conversation →