Physical Mail API
Send real letters, postcards, and parcels with a single API call. Print, stuff, and post — all handled by Mailsflux. 180+ countries, full tracking, address validation included.
import { Mailsflux } from 'mailsflux-sdk';
const mf = new Mailsflux('mf_live_sk_•••••••');
// Send a physical letter
const letter = await mf.mail.send({
type: 'letter',
from: {
name: 'Acme Corp',
address: '123 Market St',
city: 'San Francisco',
state: 'CA',
zip: '94105',
country: 'US',
},
to: {
name: 'John Smith',
address: '456 Main Ave',
city: 'New York',
state: 'NY',
zip: '10001',
country: 'US',
},
template: 'invoice-letter',
vars: { invoiceId: 'INV-2026-0042', amount: '$1,200.00' },
});
// { id: 'ltr_01KX...', status: 'printing', eta: '2026-04-14' }What's included
Send A4/A5 letters in branded envelopes. Supports full-color printing, custom letterheads, and duplex printing.
4×6 and 6×9 full-color postcards with custom front artwork and variable back content. Ideal for re-engagement and direct mail campaigns.
Send physical packages via integrated carrier APIs. Supports domestic and international shipping with rate shopping.
Every address is validated and standardized before printing. AI-powered correction catches common formatting errors. Bounce rate under 0.1%.
Full node-by-node shipment tracking from print to delivery. Webhook events on status changes keep your system in sync.
Domestic postal networks, DHL, and FedEx integrations for global coverage. Carrier selection is automatic based on destination and speed.
Carrier network
Start sending physical mail today
Free plan includes 100 physical mail pieces/month. No credit card required.