MiniMarkdown

MiniMarkdown converts XLSX workbooks into deterministic GitHub-Flavored Markdown. The repository maintains matching C#, Rust, and Node.js implementations with exact-output tests, bounded native conversion, command-line tools, and a browser comparison lab compiled to WebAssembly.

Try the C# AOT and Rust WebAssembly converters in your browser

Files selected in the browser stay on the device. The demo sends no workbook data to a server.

Implementations

	C#	Rust	Node.js
Library	.NET Standard 2.0 / .NET Framework 4.6.2	Rust crate	JavaScript + TypeScript declarations
CLI	.NET Framework 4.6.2	Native binary	Node.js 20+
Browser	.NET WebAssembly AOT	wasm32-unknown-unknown	Native only
Native shared strings	Temporary-file backed	Temporary-file backed	Temporary-file backed
Exact output	CRLF UTF-8 Markdown	CRLF UTF-8 Markdown	CRLF UTF-8 Markdown

Both implementations follow ARCHITECTURE.md, the authoritative cross-language behavior and resource contract.

Output

Each non-empty worksheet becomes a Markdown section and table:

## Data

| Name | Active | Date |
| --- | --- | --- |
| Alice | TRUE | 2023-03-15 |

MiniMarkdown preserves internal sparse rows and columns, escapes Markdown cell content, emits cached formula results, and formats recognized dates and times consistently. It does not evaluate formulas or process charts, images, macros, OCR, XLS, or XLSB.

CLI

C#:

dotnet build csharp/MiniMarkdown.sln -c Release
./csharp/src/MiniMarkdown.Cli/bin/Release/net462/minimarkdown.exe report.xlsx -o report.md

Rust:

cargo run --manifest-path rust/Cargo.toml --release -- report.xlsx -o report.md

Node.js:

npm ci --prefix node
npm run build --prefix node
node node/dist/cli.js report.xlsx -o report.md

Both CLIs write to standard output when -o is omitted and accept - for standard input.

Libraries

C#:

using (Stream input = File.OpenRead("report.xlsx"))
using (TextWriter output = File.CreateText("report.md"))
{
    new MiniMarkdown.XlsxConverter().Convert(input, output);
}

Rust:

use minimarkdown::{ConversionOptions, XlsxConverter};

let mut input = std::fs::File::open("report.xlsx")?;
let mut output = std::fs::File::create("report.md")?;
XlsxConverter::convert_seekable(
    &mut input,
    &mut output,
    &ConversionOptions::default(),
)?;

TypeScript / JavaScript:

import { convertFile, convertStream } from "minimarkdown";

await convertFile("report.xlsx", "report.md");
await convertStream(input, output);

Caller-owned streams remain open. Native non-seekable input is copied to a bounded temporary file because XLSX entries must be revisited.

Validation

Run every maintained native implementation and WebAssembly compile check:

./scripts/Validate-All.ps1

Build the complete browser test site:

dotnet workload install wasm-tools
rustup target add wasm32-unknown-unknown
cargo install wasm-pack --locked
./scripts/Build-Web.ps1

The generated static site is written to artifacts/site. Use ./scripts/Build-Web.ps1 -SkipAot for a faster local integration build; GitHub Pages always uses full C# AOT publishing and optimized Rust WebAssembly.

GitHub Pages

.github/workflows/deploy-pages.yml validates both native implementations, builds both browser engines, enables GitHub Pages, and deploys artifacts/site on pushes to main or manual dispatch. If repository or organization policy blocks automatic enablement, set Pages > Build and deployment > Source to GitHub Actions once.

Azure resources and Azure CLI are not required for GitHub Pages. The site is fully static and runs conversion in the browser.

Agent Skill

Install the MiniMarkdown XLSX conversion skill for GitHub Copilot, Claude Code, Cursor, Codex, and other compatible agents:

npx skills add shps951023/MiniMarkdown

The skill is defined in skills/minimarkdown-xlsx/SKILL.md. After the repository is public and this change is pushed, the first installation registers anonymous telemetry and makes the skill eligible to appear at skills.sh/shps951023/MiniMarkdown. skills.sh hosts the skill catalog; the Node.js package itself remains sourced from this repository.

Benchmarks

Run a quick MiniMarkdown smoke test:

./scripts/Run-Benchmark.ps1 -Tools minimarkdown -Iterations 1 -Warmups 0 -Filter basic

Run the full isolated-process comparison with MiniMarkdown, anydoc, and MarkItDown:

./scripts/Run-Benchmark.ps1

See csharp/benchmarks/README.md for corpus, metrics, and reference-tool setup. MiniMarkdown exact-output tests are authoritative; reference converters are compared semantically.