Cobra 🧾🎙️ · talk to Telegram, get paid with PayPal

Cobra is a Telegram assistant that bills your clients and chases payments for you, with PayPal. Send it a voice note like:

“Bill Marta Garcia, [email protected], 350 dollars for the logo design, due in 15 days.”

Cobra transcribes it, understands who, how much, what for and when, and shows you the invoice. Tap ✅ Send with PayPal and your client gets a real PayPal invoice by email, payable with PayPal or card. From there Cobra works on its own:

• 💸 Instant payment alerts: a PayPal webhook tells Cobra the moment you're paid, and Cobra tells you.
• 🔔 Who owes me: unpaid and overdue invoices at a glance. One tap and the AI writes a polite reminder; you see it before PayPal sends it.
• ⏰ Overdue alerts: Cobra checks every hour, warns you once when an invoice goes past its due date, and catches any payment whose webhook was missed.
• 📊 Dashboard inside Telegram: a Mini App built with AG Grid. Sort, filter, search and get a CSV for your accountant in your chat.
• 📱 QR to get paid in person, generated by PayPal for that invoice.
• 📊 This month: what you billed and what you collected, per currency.
• 🧠 Remembers your clients: next time, “bill Marta 200 for the banner” is enough.
• ✏️ Fix anything by voice: “make it 400”, “due next Friday”.
• 🌐 English and Spanish.

Nothing is ever sent to a client without your tap.

Why

Freelancers lose unpaid hours writing invoices and chasing late payments, and most of them run their business from a phone and a chat app, not from accounting software. Cobra puts PayPal invoicing where they already are, and turns the boring part into a 10-second voice note.

Demo video

Watch Cobra in 2 minutes

Try it

• Bot: @CobraInvoice_bot on Telegram (PayPal sandbox: no real money moves). Open the 📊 Invoices button for the dashboard.
• Fastest way: after sending an invoice, tap 🧪 Simulate payment (sandbox). Cobra records a test payment through PayPal's API and the alert arrives through the real webhook. This button only exists in sandbox mode.
• To pay as a client instead, open 🔗 Payment page and log in with any PayPal sandbox personal account (developer.paypal.com → Testing Tools → Sandbox Accounts).
• Use an example.com address, or your own, as the client's email.

How it works

Telegram ──webhook──▶ Cloudflare Worker (src/worker.js)
                        ├─ Workers AI · Whisper large v3 turbo: voice → text
                        ├─ Workers AI · Llama 3.3 70B: text → intent + invoice JSON, corrections, reminder notes
                        ├─ D1 (SQLite): users, client book, drafts, invoices, processed events
                        ├─ PayPal REST (src/paypal.js)
                        │    OAuth2 client credentials
                        │    Invoicing v2: create (idempotent), send, show, remind, generate QR code
                        │    Webhooks: register + verify-webhook-signature
                        ├─ /paypal/webhook ◀── INVOICING.INVOICE.PAID / CANCELLED / REFUNDED
                        ├─ /tick ◀── clock Worker: overdue alerts, missed-webhook check
                        └─ /app ── Telegram Mini App with AG Grid Community

Safety and reliability details:

• Human in the loop: the AI only prepares drafts and reminder texts; creating, sending and reminding happen after an explicit tap.
• No double billing: invoice creation uses a PayPal-Request-Id per draft, and a draft that was created but not sent is reused on retry.
• Verified webhooks: every PayPal event is checked with verify-webhook-signature against our webhook id, and deduplicated by event id.
• Missed webhook? Still right: “Who owes me” double-checks unpaid invoices with PayPal before listing them.
• Signed Mini App sessions: every dashboard request is checked against Telegram's initData signature, so you only ever see your own invoices.
• Validated AI output: amounts become integer cents, emails are validated (spoken emails like “marta at gmail dot com” are normalized), past due dates are dropped, unknown currencies fall back to the user's default.

Run your own

Requirements: Node 22+, a Cloudflare account (free plan works), a PayPal developer account (free sandbox), a Telegram bot from @BotFather.

npm test                                   # unit + conversation tests, no network
npx wrangler d1 create cobra-bot           # put the id in wrangler.toml
npx wrangler d1 migrations apply cobra-bot --remote
npx wrangler secret put BOT_TOKEN          # from @BotFather
npx wrangler secret put WEBHOOK_SECRET     # any long random string
npx wrangler secret put PAYPAL_CLIENT_ID   # developer.paypal.com → Apps & Credentials (Sandbox)
npx wrangler secret put PAYPAL_CLIENT_SECRET
npx wrangler deploy

Then open https://<your-worker>/setup?secret=<WEBHOOK_SECRET> once. It registers the Telegram webhook, the command menu and the PayPal webhook, and prints the PayPal webhook id. Save it:

npx wrangler secret put PAYPAL_WEBHOOK_ID

PAYPAL_ENV in wrangler.toml switches between sandbox and live.

Project layout

File	What
src/worker.js	HTTP routes: Telegram webhook, PayPal webhook, setup
src/bot.js	Conversation: drafts, sending, alerts, reminders, QR, totals, settings
src/paypal.js	PayPal REST client (OAuth2, Invoicing v2, webhooks)
src/miniapp.js, src/webapp.js	Mini App page, Telegram signature check, CSV
src/ai.js	Whisper + Llama prompts and output validation
src/db.js	D1 queries
src/render.js	All texts (EN/ES) and formatting
migrations/	D1 schema
test/	node --test suite with a SQLite D1 shim and fake PayPal/Telegram

License

MIT