Imported from jeremylongshore/tons-of-skills-marketplace (plugins/saas-packs/webflow-pack/skills/webflow-common-errors/SKILL.md). Install upstream with npx skills add jeremylongshore/tons-of-skills-marketplace --skill webflow-common-errors. Copyright stays with the author (MIT).

Webflow Common Errors

Overview

Quick reference for the most common Webflow Data API v2 errors, their root causes, and concrete solutions. Covers every HTTP status code the API returns.

Prerequisites

• webflow-api SDK installed
• API token configured
• Access to application logs

HTTP Error Reference

400 Bad Request — Invalid Input

{ "code": "validation_error", "message": "Invalid field data" }

Common causes:

• Missing required field (name and slug are always required for CMS items)
• Wrong field type (sending string for a Number field)
• Invalid slug format (must be lowercase, hyphens only, no spaces)
• Bulk request exceeds 100 items

Fix:

// Check collection schema before creating items
const collection = await webflow.collections.get(collectionId);
const requiredFields = collection.fields?.filter(f => f.isRequired);
console.log("Required fields:", requiredFields?.map(f => `${f.slug} (${f.type})`));

// Validate slug format
function isValidSlug(slug: string): boolean {
  return /^[a-z0-9]+(?:-[a-z0-9]+)*$/.test(slug);
}

401 Unauthorized — Invalid Token

{ "code": "unauthorized", "message": "Not authorized" }

Common causes:

• Token revoked or expired
• Token copied with extra whitespace
• Using v1 API key format with v2 endpoints

Fix:

# Verify token works
curl -s https://api.webflow.com/v2/sites \
  -H "Authorization: Bearer $WEBFLOW_API_TOKEN" \
  -w "\nHTTP Status: %{http_code}\n"

# Check for whitespace issues
echo -n "$WEBFLOW_API_TOKEN" | wc -c

// Programmatic token check
async function verifyToken(): Promise<boolean> {
  try {
    await webflow.sites.list();
    return true;
  } catch (err: any) {
    if (err.statusCode === 401) {
      console.error("Token invalid. Generate new token at developers.webflow.com");
      return false;
    }
    throw err;
  }
}

403 Forbidden — Missing Scope

{ "code": "forbidden", "message": "Insufficient permissions" }

Common causes:

• Token missing required scope (e.g., calling CMS write with only cms:read)
• Site token used for a different site
• OAuth app not authorized for the scope

Fix:

// Required scopes by operation
const SCOPE_MAP: Record<string, string> = {
  "sites.list": "sites:read",
  "sites.publish": "sites:write",
  "collections.list": "cms:read",
  "collections.items.createItem": "cms:write",
  "pages.list": "pages:read",
  "forms.list": "forms:read",
  "products.list": "ecommerce:read",
  "products.create": "ecommerce:write",
  "orders.list": "ecommerce:read",
  "orders.refund": "ecommerce:write",
};

Generate a new token with the correct scopes at https://developers.webflow.com.

404 Not Found — Wrong Resource ID

{ "code": "not_found", "message": "Resource not found" }

Common causes:

• Wrong site_id, collection_id, or item_id
• Resource deleted
• Using staging ID against live endpoint (or vice versa)

Fix:

// Discovery chain: always start from sites.list()
async function discoverResources() {
  const { sites } = await webflow.sites.list();
  console.log("Sites:", sites?.map(s => `${s.displayName}: ${s.id}`));

  for (const site of sites!) {
    const { collections } = await webflow.collections.list(site.id!);
    console.log(`  Collections in ${site.displayName}:`);
    for (const col of collections!) {
      console.log(`    ${col.displayName}: ${col.id}`);
    }
  }
}

409 Conflict — Duplicate Resource

{ "code": "conflict", "message": "Item with slug already exists" }

Common causes:

• CMS item with same slug already exists in collection
• Trying to create a resource that already exists

Fix:

// Check for existing slug before creating
async function createOrUpdate(collectionId: string, slug: string, fieldData: Record<string, any>) {
  const { items } = await webflow.collections.items.listItems(collectionId);
  const existing = items?.find(i => i.fieldData?.slug === slug);

  if (existing) {
    return webflow.collections.items.updateItem(collectionId, existing.id!, { fieldData });
  }
  return webflow.collections.items.createItem(collectionId, { fieldData: { slug, ...fieldData } });
}

429 Too Many Requests — Rate Limited

HTTP/1.1 429 Too Many Requests
Retry-After: 60

Common causes:

• Exceeded per-key rate limit
• Site publish called more than once per minute
• Rapid-fire requests without throttling

Fix:

// The SDK auto-retries 429s with exponential backoff.
// For manual control:
async function waitForRateLimit(retryAfterSeconds: number) {
  console.log(`Rate limited. Waiting ${retryAfterSeconds}s...`);
  await new Promise(r => setTimeout(r, retryAfterSeconds * 1000));
}

See webflow-rate-limits for comprehensive rate limit handling.

500/502/503 — Webflow Server Error

Fix:

# 1. Check Webflow status
curl -s https://status.webflow.com/api/v2/status.json | jq '.status'

# 2. Retry with backoff (SDK handles this automatically)
# 3. If persistent, check Webflow status page and open support ticket

Quick Diagnostic Commands

# Test API connectivity
curl -s -o /dev/null -w "%{http_code}" \
  -H "Authorization: Bearer $WEBFLOW_API_TOKEN" \
  https://api.webflow.com/v2/sites

# Check rate limit headers
curl -v -H "Authorization: Bearer $WEBFLOW_API_TOKEN" \
  https://api.webflow.com/v2/sites 2>&1 | grep -i "x-ratelimit\|retry-after"

# List sites (quick token verification)
curl -s -H "Authorization: Bearer $WEBFLOW_API_TOKEN" \
  https://api.webflow.com/v2/sites | jq '.sites[].displayName'

# Check Webflow platform status
curl -s https://status.webflow.com/api/v2/status.json | jq '.status.description'

Error Handling Pattern

import { WebflowClient } from "webflow-api";

async function resilientCall<T>(
  operation: () => Promise<T>,
  label: string
): Promise<T> {
  try {
    return await operation();
  } catch (err: any) {
    const status = err.statusCode || err.status;

    const actionMap: Record<number, string> = {
      400: "Fix request payload — check field names and types",
      401: "Rotate token at developers.webflow.com",
      403: "Add missing scope to token",
      404: "Verify resource IDs with discovery chain",
      409: "Handle duplicate — update instead of create",
      429: "Wait for Retry-After header (SDK auto-retries)",
      500: "Webflow server error — retry later",
    };

    console.error(`[${label}] HTTP ${status}: ${actionMap[status] || "Unknown error"}`);
    console.error(`  Message: ${err.message}`);
    console.error(`  Body: ${JSON.stringify(err.body)}`);

    throw err;
  }
}

Escalation Path

1. Check error code against this reference
2. Run diagnostic commands above
3. Collect evidence with webflow-debug-bundle
4. Check Webflow Status
5. Open support ticket with request ID and error details

Output

• Identified error cause from HTTP status code
• Applied targeted fix
• Verified resolution

Resources

• Webflow API Error Codes
• Webflow Status Page
• Rate Limits Reference

Next Steps

For comprehensive debugging, see webflow-debug-bundle.