The email infrastructure
for autonomous payment collection.
Developers building payment agents need primitives to send invoices with payment links, track whether recipients opened and paid, and follow up on overdue amounts. Mailgent provides the email API so your agent can manage the entire collection cycle via email.
API Primitives used
mail.sendSend payment requests
Compose and send emails with payment links, invoice details, and due dates from your agent's identity.
mail.list_messagesTrack responses
Monitor for payment confirmations, disputes, or questions from recipients.
mail.replyFollow up on overdue
Reply in-thread with reminders for unpaid invoices. Escalate tone progressively as deadlines pass.
mail.update_labelsTrack payment status
Label threads as sent, reminded, paid, or overdue. Your agent maintains a clean collection pipeline.
Getting paid should not require chasing people.
Sending an invoice is the easy part. The hard part is following up when it goes unpaid — checking status, sending reminders, answering payment questions, and escalating when deadlines pass. Most businesses lose weeks of cash flow to this manual chase, and the longer an invoice sits unpaid, the less likely it gets paid at all.
Developers building collection agents need email infrastructure that sends payment requests, detects responses, and follows up automatically. Mailgent provides mail.send for initial invoices, mail.list_messages to track replies, mail.reply for follow-ups, and mail.update_labels to track payment status.
How to build it.
mail.sendSend payment request
Your agent sends a professional payment email using mail.send, including the amount owed, due date, and a payment link. Each email goes from a dedicated billing identity.
mail.list_messagesMonitor for payment
The agent checks for replies using mail.list_messages — payment confirmations, disputes, or questions. It labels threads with mail.update_labels to track status.
mail.replyFollow up on overdue
If payment is not received by the due date, the agent sends follow-up reminders using mail.reply. It escalates tone and frequency based on how overdue the payment is.
Example prompt
“Send payment reminders to all clients with invoices overdue by more than 7 days. Include the original amount and payment link. Label any that are 30+ days overdue as 'escalate'.”
What developers build.
Invoice delivery
Build agents that generate and send invoices on a schedule — monthly retainers, project milestones, or usage-based billing.
Overdue reminders
Build agents that send progressively urgent reminders at 7, 14, and 30 days past due, then escalate to your finance team.
Payment confirmation
Build agents that detect payment confirmation emails, label threads as paid, and send thank-you receipts automatically.
Dispute handling
Build agents that detect payment disputes in replies, label them for review, and acknowledge receipt to the sender while routing to your billing team.
Why not use billing software?
Billing platforms send the first invoice but leave follow-up to you. Their reminder features are rigid — fixed intervals, generic templates, no awareness of the conversation context. When a customer replies with a question, the platform does not know what to do.
Mailgent gives you primitives to build the complete collection workflow. mail.send delivers invoices, mail.list_messages detects replies, mail.reply handles follow-ups in-thread. Your agent adapts its approach based on context, not a fixed template.
Dedicated billing identity
Payment emails come from a separate agent identity. Billing threads are isolated from other communications.
No payment data stored
Mailgent handles email delivery, not payment processing. Card details never touch the email infrastructure.
Delivery audit trail
Every payment request and reminder is logged. Prove exactly when each invoice was sent and each follow-up delivered.