How to Integrate Lovable with Smartsheet

Before writing any code, you need a Smartsheet API token — this is the credential your Edge Function will use to authenticate every request to the Smartsheet API. To generate one, log into Smartsheet at app.smartsheet.com and click your account avatar in the top-right corner. Select 'Personal Settings' from the dropdown, then navigate to the 'API Access' tab. Click 'Generate new access token', give it a descriptive name like 'Lovable Integration', and copy the token immediately — Smartsheet only shows it once. If you lose it, you'll need to revoke it and generate a fresh one. With the token copied, switch to your Lovable project. Click the '+' icon at the top of the screen to open the panels, then select the 'Cloud' tab. Scroll to the 'Secrets' section and click 'Add secret'. In the name field, type SMARTSHEET_API_TOKEN exactly as shown — the Edge Function code will reference this exact name. Paste your token into the value field and click Save. The secret is now encrypted and will only be accessible from server-side Edge Functions, never from your frontend code. Lovable's security infrastructure blocks approximately 1,200 hardcoded API keys per day — always use Secrets rather than pasting keys into chat or code.

Now you'll create the Edge Function that acts as a secure server-side proxy for all Smartsheet API calls. This function lives in your project's supabase/functions/ directory and runs on Deno — it retrieves the API token from environment variables (never exposed to the browser), makes requests to the Smartsheet REST API, and returns the results to your frontend. Paste the following prompt into Lovable's chat to scaffold the Edge Function. Lovable will generate the function file, deploy it to Cloud, and wire up the necessary CORS headers automatically. The function accepts a POST request with a JSON body specifying the operation type (get_sheet, get_rows, create_row, update_row, delete_row) and the relevant parameters. This single function handles all Smartsheet operations through an action-based routing pattern, keeping your architecture simple while giving you full CRUD capability.

1// supabase/functions/smartsheet-proxy/index.ts
2import { serve } from "https://deno.land/std@0.168.0/http/server.ts";
3
4const SMARTSHEET_BASE = "https://api.smartsheet.com/2.0";
5
6const corsHeaders = {
7  "Access-Control-Allow-Origin": "*",
8  "Access-Control-Allow-Headers": "authorization, x-client-info, apikey, content-type",
9};
10
11serve(async (req) => {
12  if (req.method === "OPTIONS") {
13    return new Response("ok", { headers: corsHeaders });
14  }
15
16  const apiToken = Deno.env.get("SMARTSHEET_API_TOKEN");
17  if (!apiToken) {
18    return new Response(JSON.stringify({ error: "SMARTSHEET_API_TOKEN not configured" }), {
19      status: 500,
20      headers: { ...corsHeaders, "Content-Type": "application/json" },
21    });
22  }
23
24  const { action, sheetId, params = {} } = await req.json();
25  const headers = {
26    Authorization: `Bearer ${apiToken}`,
27    "Content-Type": "application/json",
28  };
29
30  let url = "";
31  let method = "GET";
32  let body: string | undefined;
33
34  switch (action) {
35    case "get_sheet":
36      url = `${SMARTSHEET_BASE}/sheets/${sheetId}`;
37      break;
38    case "get_rows":
39      const queryStr = params.query ? `?${new URLSearchParams(params.query).toString()}` : "";
40      url = `${SMARTSHEET_BASE}/sheets/${sheetId}/rows${queryStr}`;
41      break;
42    case "create_row":
43      url = `${SMARTSHEET_BASE}/sheets/${sheetId}/rows`;
44      method = "POST";
45      body = JSON.stringify([{ cells: params.cells, toBottom: true }]);
46      break;
47    case "update_row":
48      url = `${SMARTSHEET_BASE}/sheets/${sheetId}/rows`;
49      method = "PUT";
50      body = JSON.stringify([{ id: params.rowId, cells: params.cells }]);
51      break;
52    case "delete_row":
53      url = `${SMARTSHEET_BASE}/sheets/${sheetId}/rows?ids=${params.rowId}`;
54      method = "DELETE";
55      break;
56    default:
57      return new Response(JSON.stringify({ error: `Unknown action: ${action}` }), {
58        status: 400,
59        headers: { ...corsHeaders, "Content-Type": "application/json" },
60      });
61  }
62
63  const response = await fetch(url, { method, headers, body });
64  const data = await response.json();
65
66  return new Response(JSON.stringify(data), {
67    status: response.status,
68    headers: { ...corsHeaders, "Content-Type": "application/json" },
69  });
70});

With the Edge Function deployed, you can now build the frontend component that fetches and displays Smartsheet data. The key to working with Smartsheet's API is understanding that rows contain a 'cells' array, where each cell has a 'columnId' referencing the column definition and a 'value' containing the actual data. You need to first fetch the sheet to get column definitions, then map cell values to column names for display. Paste the following prompt into Lovable's chat to generate a React component that calls your Edge Function, maps column IDs to column names, and displays the sheet data in a table. Lovable will generate the component with proper loading states, error handling, and TypeScript types derived from the Smartsheet API response shape. The component uses shadcn/ui's Table component for a polished display that matches your app's design system.

Reading data is useful, but most integrations also need to create and update rows. Smartsheet's row creation API requires you to specify cell values as an array of objects, each with a 'columnId' (the numeric ID from the sheet's column definitions) and a 'value'. This means you must have the column IDs available at the time of form submission — either hardcode them from your sheet's column definitions, or fetch them dynamically from the Edge Function. The safest approach is to fetch the sheet structure once on component mount, store the column definitions in state, and reference those column IDs when building the cell array for row creation. When updating an existing row, you additionally need the row's ID — available from the rows returned by your initial fetch. For complex integrations with many sheets, RapidDev's team can help design a column mapping configuration that keeps your column IDs maintainable as sheets evolve. The following prompt generates a form that creates new rows with proper column ID mapping.

Smartsheet supports file attachments on rows — a common requirement for project management apps where teams upload documents, images, or status reports to specific tasks. The Smartsheet API handles attachments via multipart form data uploads at /sheets/{sheetId}/rows/{rowId}/attachments. Your Edge Function needs a separate handler for file uploads since the request format differs from JSON API calls. For real-time updates when Smartsheet data changes, Smartsheet offers webhooks — but note that setting up webhook callbacks requires a publicly accessible endpoint URL. Your deployed Lovable app's Edge Function URL works perfectly as a webhook receiver. Register the webhook in Smartsheet at app.smartsheet.com → Account → Personal Settings → API Access → Webhooks, providing your Edge Function URL as the callback URL. Smartsheet will send a verification challenge first — your Edge Function must respond with the challenge token to complete registration. After registration, Smartsheet sends POST requests to your endpoint whenever rows are created, updated, or deleted in the subscribed sheet.