Changelog

October 14, 2026Copy Anchor Link

• letter.updated event: a letter changed in the dashboard before production (send date, address, file, variables, printing, Correios services or reference) sends letter.updated, with the letter as it is now. See Letters and statuses.
• Confirmation page: it now lives at https://verifica.cartaflow.com.br/{your account id}/{page token} (hosted_page_url). It shows your company's contact (Configurações > Empresa, Settings > Company) and, after the right code, offers to share the device's location. confirmation gets new fields: location.postal_code, location.latitude, location.longitude, user_agent, device, client and precise_location. See The confirmation page.

October 13, 2026Copy Anchor Link

First version of the API (v1).

It includes:

• Letters: create from a PDF uploaded as a file (multipart), by URL, in base64 or with the two-step upload (POST /v1/uploads, for PDFs up to 10 MB); retrieve, list and cancel. A letter that fails in production moves to failed and the amount goes back to the balance. See Letters and statuses and Document and address area.
• PDF variables: markers such as {{name}} in a PDF, filled in with variables for each letter. See Document and address area.
• Correios services: registered letters (with a tracking code in tracking_code), return receipt (AR) and restricted delivery (MP), in postal_services. See Letters and statuses.
• Scheduling: send_date schedules a letter for a date, charged on that date. See Scheduling.
• Price calculation: POST /v1/letters/quote simulates a letter with the same body as creation, without creating or charging anything. See Pricing and balance.
• Addresses: only name, postal code and number are required; the rest is filled in from the postal code. See Addresses in Brazil.
• Physical address verification: a letter with a code and your brand, from the CartaFlow letter template (customizable in letter) or from your own PDF with the {{OTP_CODE}} marker, confirmed on a hosted page or in your app. A verification records where it was created (source) and how it was confirmed (confirmation), and can be revoked after production (revoked, with no refund). See Physical address verification.
• Postal codes: look up the address of a Brazilian postal code (CEP).
• Account and balance: account details, prepaid balance and transactions.
• Events and webhooks: one event per status change, delivered with a Standard Webhooks signature, and a test event sent from the dashboard. See Webhooks.

The full reference of every endpoint is in the API reference.