Excel workbooks · Browser-local · MCP-ready

Your spreadsheet.
On your terms.

Open, edit and embed Excel sheets wherever your team works. Keep local files on your device, or ask your AI to make a sheet you can share.

Try the live workbook ↓Connect your assistant ↗

No account needed to open, edit or download. Built on GridCraft WASM.

This introduction is an Excel file

Meet Hammer Sheets. Inside Hammer Sheets.

A live workbook, not a screenshot. Read Welcome, then switch to Try it to edit the sample data and explore the chart.

Changes affect your copy. The original stays unchanged.Open full editor ↗Download XLSX ↓

Why I built it

The workbook was already there.
The viewer was the hard part.

I kept needing to show private Excel sheets linked from Jira and other tools in our org. Microsoft’s viewer was awkward to embed in our setup, and I wanted control over file access and CORS.

Chart.js required too much setup for my workflow. I needed more than charts: cells, formulas, multiple sheets, editing, and XLSX downloads together.

Hammer Sheets brings those workflows to the browser with WebAssembly. Credit to GridCraft and the ArtCraft team for the Rust spreadsheet engine and existing WASM support. Hammer Labs adds hosting, sharing, embedding, and MCP integration.

Already have a spreadsheet?

Paste an HTTPS workbook link, or open a file from your device inside the editor.

Give it a real workbook.

ONE-CLICK DEMO

Sales, at a bigger scale.

24,000 synthetic sales records, a summary dashboard, and two charts. Original sample generated with GridCraft. Explore the numbers, edit a cell, then download your copy.

Open sales dashboard →

REAL-WORLD XLSX · 3.6 MB

A building's energy story.

The U.S. Department of Energy's Metered Data Analysis Workbook: 13 sheets, 18 chart definitions, and more than 26,000 metered-data rows. Explore load profiles, rolling averages, scatter plots, and heat maps.

Download DOE workbook ↗

Then open Hammer Sheets and choose Open file. DOE's server does not allow direct browser imports. Grouped shapes and some external PivotTable references are unsupported; preserve the original.

Source and tutorial — U.S. Department of Energy ↗

01 / CREATE

Ask in your own words.

Connect MCP to Claude or another compatible assistant. Turn rows, numbers, and formulas into an editable sheet.

02 / SHARE

A sheet inside a link.

Small sheets travel in the link itself. No account or file upload for self-contained links. Anyone with the complete link can open it.

03 / KEEP

Your work, on your terms.

Edit with GridCraft, save a draft in this browser, or download an XLSX workbook. Optional short links store encrypted snapshots for 30 days.

Hammer Sheets MCP

Give your assistant a canvas.

Three tools: create a spreadsheet, share a small XLSX file, or open an existing workbook URL.

LOCAL · MOST PRIVATE

Run on your machine

Install the Rust MCP server. Add this server configuration to a client that supports local MCP, such as Claude Desktop.

cargo install --git https://github.com/hmmrlabs/gridlink \
  --locked --bin gridlink

{
  "mcpServers": {
    "gridlink": {
      "command": "/absolute/path/to/gridlink"
    }
  }
}

Tool processing stays on your device. Your AI provider still receives what you share in the conversation.

HOSTED · NO INSTALL

Connect by URL

In a client with remote MCP support, add a custom Streamable HTTP server using this URL. Availability depends on your client's plan and connector support.

https://sheets.hammerlabs.ai/mcp

No account required. The hosted tool processes your inputs to create the link, then discards them. Hosted MCP does not store workbooks. Optional browser short links store encrypted snapshots for 30 days.

For sensitive data, choose local MCP. Editing and saved drafts stay in your browser with either option.

Small service. Clear boundaries.

Inline links hold up to 48 KiB of sheet data. They are readable by anyone who has the complete link, cannot be revoked, and may be truncated by some chat apps. Larger workbooks, up to 16 MiB, can use password-protected links after storage consent and creator sign-in. Encrypted copies expire after 30 days; send the share password separately. Local drafts are limited to 1.5 MiB per workbook and browser storage quotas; clearing site data removes them. Downloads remain available.

Optional analytics counts only aggregate events such as opening the editor, saving locally, downloading, and using MCP. No analytics cookies, document contents, filenames, source URLs, or persistent visitor IDs. Privacy signals are respected. Cloudflare necessarily processes network metadata when serving the site. Excel features unsupported by GridCraft may not survive an XLSX round-trip; keep your original.

Your spreadsheet.On your terms.