Note: SDK packages will be published at launch. This tutorial previews the API.

Process XLSX Files Server-Side

Use @mog-sdk/node to read, modify, and write Excel files in TypeScript -- no Excel installation required. The native Rust engine handles parsing, formula evaluation, and serialization.

beginner~15 min

1Install the SDK

The Node.js SDK ships prebuilt native binaries for macOS, Linux, and Windows. No Rust toolchain needed.

bash

npm install @mog-sdk/node

2Read an XLSX file

Open a workbook from disk and iterate over sheets and cells.

typescript

import { openWorkbook } from "@mog-sdk/node";

const wb = await openWorkbook("sales-report.xlsx");

// List all sheet names
for (const sheet of wb.getSheets()) {
  console.log("Sheet:", sheet.name);
}

// Read cells from the first sheet
const ws = wb.getActiveSheet();
const rows = await ws.getUsedRange();

for (const row of rows) {
  for (const cell of row) {
    console.log(`${cell.ref}: ${cell.value} (type: ${cell.type})`);
  }
}

3Evaluate formulas

The Rust compute engine evaluates 500+ Excel-compatible functions. Call calculate() to recalculate the entire workbook, then read computed values.

typescript

import { openWorkbook } from "@mog-sdk/node";

const wb = await openWorkbook("budget.xlsx");
const ws = wb.getActiveSheet();

// Trigger full recalculation
await wb.calculate();

// Read a formula cell's computed value
const total = await ws.getValue("D10"); // =SUM(D2:D9)
console.log("Total:", total);

// Read the formula text itself
const formula = await ws.getFormula("D10");
console.log("Formula:", formula); // "=SUM(D2:D9)"

4Modify cells and write back

Set cell values, add formulas, and save the workbook back to XLSX.

typescript

import { openWorkbook, save } from "@mog-sdk/node";

const wb = await openWorkbook("template.xlsx");
const ws = wb.getActiveSheet();

// Update values
await ws.setCell("A1", "Product");
await ws.setCell("B1", "Revenue");
await ws.setCell("A2", "Widget A");
await ws.setCell("B2", 45000);
await ws.setCell("A3", "Widget B");
await ws.setCell("B3", 62000);

// Add a formula
await ws.setCell("B4", "=SUM(B2:B3)");

// Recalculate and save
await wb.calculate();
await save(wb, "output.xlsx");

console.log("Saved output.xlsx");

5Batch processing multiple files

Process an entire directory of XLSX files. Each workbook is independent, so you can parallelize with Promise.all.

typescript

import { openWorkbook, save } from "@mog-sdk/node";
import { readdir } from "node:fs/promises";
import { join } from "node:path";

async function addSummaryRow(filePath: string) {
  const wb = await openWorkbook(filePath);
  const ws = wb.getActiveSheet();

  const lastRow = (await ws.getUsedRange()).length + 1;
  await ws.setCell(`A${lastRow}`, "TOTAL");
  await ws.setCell(`B${lastRow}`, `=SUM(B2:B${lastRow - 1})`);

  await wb.calculate();
  await save(wb, filePath.replace(".xlsx", "-with-totals.xlsx"));
}

const dir = "./reports";
const files = (await readdir(dir)).filter((f) => f.endsWith(".xlsx"));

await Promise.all(files.map((f) => addSummaryRow(join(dir, f))));

console.log(`Processed ${files.length} files`);

Process XLSX Files Server-Side

1Install the SDK

2Read an XLSX file

3Evaluate formulas

4Modify cells and write back

5Batch processing multiple files

Next steps

Embed a Spreadsheet in Next.js

Use Mog from Python

API Reference

Getting Started