Overview
ConvertKit (now rebranded as Kit) is an email-first platform for creators - bloggers, podcasters, and course builders. Its landing page builder creates minimal, fast-loading opt-in and product sales pages that feed directly into ConvertKit subscriber lists with automatic tagging. While ConvertKit excels at email automation, it does not surface per-subscriber UTM attribution or offer spreadsheet export from landing pages. LeadToSheet captures every signup alongside its traffic source in Google Sheets, giving creators a simple analytics layer for tracking which promotional channels drive the most subscribers.
Implementation checklist
- 1
Add the LeadToSheet SDK via ConvertKit custom code
In the ConvertKit landing page editor, open the page settings and look for the Custom Code or HTML section. Paste the SDK snippet in the footer/body end area. ConvertKit landing pages support custom JavaScript, which allows the SDK to run alongside the built-in opt-in form.
Tip: If you embed ConvertKit forms on an external website (e.g., your blog), add the LeadToSheet SDK to the host page instead of the ConvertKit landing page settings.
ConvertKit custom code
<script src="https://cdn.leadtosheet.com/sdk.min.js" data-client="YOUR_CLIENT_KEY"></script> - 2
Check subscriber tag and form field configuration
ConvertKit landing page forms typically collect email and first name, with automatic subscriber tagging configured in the form settings. LeadToSheet captures the visible form fields (email, name) and any hidden fields you add. The subscriber tag assignment happens server-side in ConvertKit and is not captured in Sheets, but you can add a hidden field that mirrors the tag name.
- 3
Test with a tagged UTM link from a promotion
Share your ConvertKit landing page link with UTM parameters (e.g., ?utm_source=podcast&utm_medium=episode_link). Submit a test entry and verify the Google Sheet shows both the form data and the UTM parameters. Confirm the subscriber also appears in your ConvertKit list.
Customization ideas
Track promotional channel performance for creators
Creators promote on podcasts, YouTube descriptions, newsletter cross-promotions, and social media. Use unique UTM-tagged links for each channel. LeadToSheet captures the UTM values with every signup, giving you a Google Sheet pivot table that shows subscriber count by promotional channel.
Mirror subscriber tags in Sheets via hidden fields
ConvertKit automatically tags subscribers based on which form they used, but this tag lives only in ConvertKit. Add a hidden form field with the tag name (e.g., 'source_tag': 'podcast_listeners') so LeadToSheet logs it in Sheets, enabling tag-based filtering without ConvertKit access.
Track product sales page conversions alongside opt-ins
ConvertKit landing pages can sell digital products directly. Use data-leadtosheet-tab to route product purchase form submissions to a 'Sales' tab and email opt-in forms to a 'Subscribers' tab, keeping revenue data separate from lead capture in the same spreadsheet.
Troubleshooting
ConvertKit form redirects to a success page immediately
ConvertKit landing page forms may redirect to a thank-you page or an incentive download page after submission. If this redirect fires before LeadToSheet completes the sync, switch the post-submission behavior to an inline success message in ConvertKit's form settings, or configure the redirect to include a brief delay.
Embedded ConvertKit forms on external sites not captured
When you embed a ConvertKit form on an external blog or website using ConvertKit's JavaScript embed code, the form renders in the host page's DOM. Add the LeadToSheet SDK to the host page (not the ConvertKit landing page settings) for the SDK to detect and capture the embedded form submissions.
Subscriber tag not appearing in Sheets
ConvertKit assigns subscriber tags server-side after the form submission. The LeadToSheet SDK captures browser-side form data and does not have access to server-side tag assignments. To include the tag in Sheets, add a hidden input field to the form with the tag name as its value.
Frequently asked questions
- ConvertKit is now called Kit. Does LeadToSheet support the rebranded version?
- Yes. The underlying form technology is the same regardless of the brand name. The LeadToSheet SDK captures form submissions from both the legacy ConvertKit and the rebranded Kit landing pages without any configuration changes.
- Why do I need Sheets if ConvertKit already tracks my subscribers?
- ConvertKit tracks subscribers for email automation but does not expose per-subscriber UTM attribution. Sheets gives you campaign-level attribution data, a backup of all signups, and a shareable format for collaborators who do not have ConvertKit access.
- Does LeadToSheet capture ConvertKit product sales data?
- LeadToSheet captures the form fields on the product sales page (email, name, product selection). Payment processing happens through ConvertKit's payment provider and is not captured for security reasons, but the product identifier and buyer contact info will appear in your Sheet.