--- title: "Add reviewed mail to an n8n workflow — Postedly" description: "Prepare fax and mail quotes in n8n using Postedly’s MCP or HTTP API. Transfer binary documents and keep a human approval step before payment." url: "https://postedly.com/agents/n8n" --- # Build the workflow up to “ready to send.” Turn approved records into a finished document and a sending quote. Postedly gives an n8n workflow a clear handoff: the file and recipient are ready, the total is known, and a person can review the order before paying. See the setup guide See example requests ## Documented workflow · untested Last tested Not yet tested n8n documents MCP OAuth credentials and multipart binary uploads. A complete Postedly workflow in n8n has not yet been verified; use a version that supports Streamable HTTP. ## Use n8n with Postedly 1. ### Connect the MCP client Use the MCP Client Tool with Postedly’s endpoint and OAuth2 credentials. Configure dynamic client registration and the exact HTTPS callback shown by your n8n instance. ``` https://postedly.com/mcp/send ``` 2. ### Pass the binary document Use authenticated HTTP upload where the credential is available, or obtain a private uploadEndpoint from postedly_prepare_document. In HTTP Request, choose Form-Data and an n8n Binary File parameter named file. 3. ### Pause for the review handoff Save the document and quote references. Route the private approval link to the authorized person through your chosen workflow, then check the existing order after checkout. ## Give it a specific request ### Prepare one approved customer letter Keep document generation, quote preparation and the approval handoff as separate workflow stages. Example request > Prepare a Postedly mailing quote for the approved PDF and recipient in this record. Return the review link for a person to approve; do not pay or send automatically. ## Transfer your file Send the actual binary property, not a JSON string containing its name. Authenticated uploads also specify the service. A prepared handoff already binds the service and accepts field file without another bearer token. Keep its short-lived URL private. - For a letter or fax, prepare a valid, unencrypted PDF no larger than 10 MiB (10,485,760 bytes). Review the saved PDF after exporting it from the draft. - For mail, have the recipient’s full US postal address and your US sender address ready. For fax, confirm the receiving US fax number and your US billing address. Check the selected service’s page and layout limits before quoting. - Review the final proof returned with the quote, including any added cover or postal layout. An upload preview alone does not establish that the final document is ready to send. [Letter requirements](https://postedly.com/services/letters) [Fax requirements](https://postedly.com/services/fax) ## Mail a check n8n can prepare a paper check drawn on your own verified US checking account. The assistant never sees your account numbers and can’t sign or pay; those steps stay with you. 1. ### Set up checks once, yourself Open Postedly’s check page in your browser, verify your email and connect your checking account. You’ll verify it with Plaid, confirm you can sign for it, set a bank passkey and save your signature. [Set up checks](https://postedly.com/checks) 2. ### Ask n8n for the check Give the payee’s exact name and US mailing address, the amount and an optional memo. Using Postedly’s check tools, n8n reads your ready accounts and drafts the check, which reserves its number and prepares a service-fee quote. Nothing is signed, charged or sent. 3. ### Review, sign and pay Open the private review link it gives you. Check the full proof, confirm with your passkey, sign and pay the service fee. The check amount is paid from your account only when the payee deposits it. 4. ### Follow the order n8n can read the order to see when the check is printed and mailed. Postedly can’t see when it clears; your bank shows that. Example request > Mail a $250 check to Riverside Little League, 400 Park Rd, Dayton, OH 45402, from my checking account. Memo: Spring registration. Send me the link to review and sign it. If n8n doesn’t show Postedly’s check tools, reconnect Postedly or refresh its tools, or write the check yourself on Postedly. ## Your approval comes before the send Prepare and quote nodes do not pay. The customer reviews the exact proof, recipient and total in the browser before Stripe Checkout. Build this pause explicitly; a schedule or workflow retry is not fresh purchase approval. [Cancellation and refund policy](https://postedly.com/refunds) ## Follow the existing order Store the order ID and check it on later runs. Treat timeouts as uncertain outcomes, and reconcile status before retrying a payment or send operation. [Check an order on Postedly](https://postedly.com/track) ## Send directly on Postedly You can use the finished document without connecting an assistant. Download the approved PDF, open Postedly, choose an available service and upload the file. Enter the destination and sender details, then review the final proof and full price before payment. You do not need your own printer or envelopes to mail a PDF through Postedly. [Open the sending form](https://postedly.com/send) [Follow a sending guide](https://postedly.com/guides) [Check services and pricing](https://postedly.com/capabilities) ## Before you start - Your n8n node version must support Postedly’s transport and OAuth flow. Uploads are limited to 10 MiB. Serialize OAuth refresh for shared credentials and protect private file links. This guide does not promise unattended payment or a prebuilt Postedly node. ## Official references Use these platform references alongside the Postedly guide. - [n8n: MCP client credentials](https://docs.n8n.io/integrations/builtin/credentials/mcp/) - [n8n: HTTP Request and binary form data](https://docs.n8n.io/integrations/builtin/core-nodes/n8n-nodes-base.httprequest/) - [Postedly connection and file-transfer guide](https://postedly.com/agent-guide.md) ## Ready to prepare a send? Use the connected assistant, or finish directly with Postedly. [Read the API guide](https://postedly.com/developers)