Velt×
SpreadJSAdd comments and co-editing, plus live presence, to your SpreadJS workbook, for your users and your AI agents. Threads stay pinned to the cell as the sheet recalculates, and every agent edit lands as a suggestion your users approve, so the question on a cell stays on that cell.
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| Q2 | Q3 | Q4 | |
|---|---|---|---|
| Revenue | 1.3M | 1.42M | 1.5M |
| Margin | 38% | 41% | 44% |
Flagged the Q3 revenue cell as an outlier and suggested the correction.
The problem
Your users expect to comment and co-edit in SpreadJS, and your AI agents need that same workbook with a human approving before they touch user work. Comments that survive SpreadJS's recalcs are a multi-quarter build, and the moment anchoring breaks, feedback lands on the wrong cell. Co-editing is the harder half: rolled by hand it means overwrites, lost work, and merge conflicts, the "my changes disappeared" bug reports, plus a websocket fleet and offline merge to keep alive. And the harder question is your agents: a useful agent needs to change the work, but an agent with write access to user content is what your buyers' security review blocks, so without a consent step you choose between an agent that is useful and an agent that is safe. Every quarter spent on this is a quarter not spent on your own product.
Velt is the review and collaboration layer built for SpreadJS: your users and your AI agents work the same workbook, with comment threads anchored to the cell, and every agent suggestion is a change a human approves before it lands.
Features
Clause 7 omits a liability cap. Suggested fix attached.
// An agent posts a suggestion as a first-class user.
await velt.comments().add({ author: agent, suggestion });
// On approve, the change fires through your webhook.Your AI agent comments and suggests on the workbook as a first-class user; a human approves or rejects, and on approve the change fires through your webhook with a permanent record.
@Maya pulled into the thread
2 Repliesimport { VeltComments } from "@veltdev/react";
<VeltComments textMode />Cell-level comments with replies and @mentions, pinned to the cell through recalcs and across multiple sheets.
Tiptap
Lexical
CodeMirror
BlockNote
React Flowplus the core library for your own editor, whiteboard, or grid
import { useVeltCrdtExtension } from "@veltdev/tiptap-crdt-react";
const extension = useVeltCrdtExtension({ editorId });CRDT shared cell state so two users write to the same workbook without overwrites.
import { VeltPresence, VeltCursor } from "@veltdev/react";
<VeltPresence />
<VeltCursor />Live named cursors and selections on the sheet, so everyone knows who is where.
Suggested a tighter figure on the rate line.
// Propose changes reviewed like a diff.
<VeltComments suggestionMode />Propose cell changes as accept-or-reject suggestions, reviewed like a diff.
Maya mentioned you on Q3 forecastmention
“@you can you review before Friday?”
Sarah replied on the Q3 threadreply
forecast.xlsx · cell B12
Ethan requested your sign-offsign-off
contract.pdf · due today
import { VeltNotificationsTool } from "@veltdev/react";
<VeltNotificationsTool />In-app, email, and Slack alerts on every comment and @mention, so a review never stalls.
await velt.versions().save({ name: "Draft v3" });
await velt.versions().restore({ id });Named checkpoints for the workbook, saved and restored by API.
const log = await velt.activities().get({ documentId });Every change to the number, every approval, exportable.
A checking agent flags the cell where a formula breaks or a number misses the model and comments on it as a first-class user; your reviewer approves the correction, and on approve the change fires through your webhook with a permanent record of who allowed what.
Setup
npm install @veltdev/react @veltdev/spreadjs-crdt-reactimport { VeltProvider } from "@veltdev/react";
<VeltProvider apiKey={API_KEY}>
<App />
</VeltProvider>// Mount Velt on SpreadJS
<VeltComments />
// + the CRDT adapter for co-editingWhy Velt
Liveblocks syncs people and agents into your app's state; Velt adds the step Liveblocks does not, every agent change on SpreadJS is a suggestion your user approves or rejects, on the record.
Enterprise
The controls your buyers' security reviews ask for, in writing.
Adding Velt to SpreadJS does not move that surface's content off your stack. Per-feature data providers keep comment content, attachments, and user PII on your own infrastructure; Velt stores only minimal identifiers.
FAQ
Both. You can ship comments alone or add co-editing via the CRDT adapter; they are independent capabilities.
Yes. Comment threads are anchored to the cell reference, not the rendered position, so they survive recalculations and cross-sheet moves.
Yes. The adapter is designed for production workbook sizes; anchoring is by cell reference, not DOM position.
Yes. An agent posts a comment or suggestion on the cell as a first-class user, and a human approves or rejects before any value changes.
Yes. Every approval fires a webhook event and is written to the audit trail, exportable for compliance.
On usage, not seats or integrations: you pay for documents with review activity in a month, with a free tier for development and early production.
Free tier. No credit card.
First comment in 5 minutes.
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