cf_ai_email_workflow

AI-powered email draft assistant built on Cloudflare’s developer platform. Try it yourself: https://cf_ai_jz.justinzhang20711.workers.dev

Overview

cf_ai_email_workflow lets a user:

• Paste a resume and target job URL.
• Kick off a Cloudflare Workflow that:
  • Fetches the job description from the URL.
  • Calls Workers AI to generate a tailored, professional email draft.
  • Persists the latest draft and a history of drafts.
• Iteratively refine the draft by sending feedback; each feedback round produces a revised email via the same Workflow.
• View and load past drafts from history.

The app is a single-page React UI talking to a Workers backend over JSON routes.

Tech Stack

Frontend

• React + TypeScript SPA, built with Vite.
• Deployed as static assets under frontend/dist and served by the Worker using the assets.directory configuration in wrangler.jsonc.
• UI features:
  • Resume + job URL form.
  • Live draft panel with status chip.
  • Feedback box for incremental refinement.
  • Past drafts panel populated from Durable Object storage.

Backend (Cloudflare)

• Cloudflare Worker

  • REST endpoints:
    • POST /start – create a new Workflow instance for a given resume and job URL.
    • POST /feedback – send a user_feedback event to an existing Workflow.
    • GET /status – query Workflow instance status.
    • GET /get-latest-draft – fetch the latest email draft text.
    • GET /list-drafts – fetch a JSON map of past drafts.
  • Typed Env bindings for:
    • STATE: Durable Object namespace.
    • EMAIL_WORKFLOW: Workflow binding.
    • AI: Workers AI binding.

• Cloudflare Workflows

  • Durable, multi-step orchestration for:
    1. Fetching and slicing the job posting HTML.
    2. Generating an initial email using a Workers AI LLM.
    3. Persisting drafts via the Durable Object.
    4. Waiting for user_feedback events and revising the email until the user signals completion.
  • Makes use of step.do and step.waitForEvent to cleanly separate external calls and long-lived waits.

• Durable Objects

  • Stores:
    • "latest-draft" – the most recent email.
    • Timestamped keys like "draft:<ISO timestamp>" – history entries with { draft, createdAt }.
  • Exposes:
    • POST /store-latest-draft – update latest draft + append history.
    • GET /get-latest-draft – read latest draft.
    • GET /list-drafts – list all drafts as a JSON object for the UI.

• Workers AI

  • Uses a hosted LLM (e.g. @cf/meta/llama-3.1-8b-instruct) via env.AI.run.
  • Prompts:
    • Initial: “Write a short professional job application email. Job: … Resume: …”
    • Revision: “Revise this email based on this user feedback: …”