You are helping me build the following AI agent workflow.

## Goal
Digital Certificate Creator & Validator: Receives candidate details via webhook to generate a branded PDF certificate, store the record, email it, and enable public ID verification.

## Specification
- What it does: Receive candidate details via webhook to instantly generate a branded PDF certificate, store the record securely, and email it directly to the recipient. You can also verify any certificate's authenticity by checking its unique ID against your public registry.
- Trigger: Triggered by an event (Event · on webhook POST request)
- Autonomy: Fully hands-off
- Expected setup effort: about an afternoon
- Tools/services involved:
  - n8n: Workflow orchestration and data storage
  - PDF Generator API: Creating professional PDF certificates from HTML templates
  - Gmail: Sending email notifications with attached certificates
  - Code: Generating unique certification IDs and processing data

## Known pitfalls, handle each one explicitly in your implementation
1. The PDF generator might fail if special characters in names are not escaped properly so sanitize input strings before passing them to the template.
2. Email delivery can be delayed or blocked by spam filters so configure SPF and DKIM records for your sending domain.
3. The Data Table may grow large over time which slows down verification queries so add an index on the certificate ID column.

## Reference implementation
https://n8n.io/workflows/11097 (workflow template)
Fetch and inspect this before building. If it matches my stack, adapt it;
if not, rebuild the pattern with my tools.

## Process requirements
1. Before building: ask me which of the listed tools I actually use and
   what my platform is (n8n / Make / code / other). Do not assume.
2. Adapt the pattern to my answers; do not force the reference stack.
3. Address every pitfall above; tell me how you handled each.
4. Provide a test plan I can run before letting this touch real data.
5. Ask before any step that sends messages, modifies data, or spends money.

Source: https://usecasesforagents.com/use-case/automated-digital-certificate-creator-validator/ via usecasesforagents.com