Live · 64 model-visible tools

MCP server for physical mail: send real letters from your AI assistant

FrankKi MCP is a live, remote hosted Model Context Protocol server for physical mail. Connect https://mcp.frankki.app to ChatGPT, Claude, Cursor or VS Code and your assistant drafts, prices, sends, tracks and manages real letters worldwide: local postal tariffs across DACH and Europe, DHL to the rest of the world. Physical mail for AI agents and people.

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https://mcp.frankki.app

live now · OAuth 2.1 + DCR source contract · scoped Bearer API keys · nothing to self-host

Works withChatGPTClaudeCursorVS Code

Create your account and start

The implemented signup flow is public and needs no manual account approval. You receive an email link to set your password, then set up your sender and scoped Bearer API key in the dashboard. Current production signup availability is not independently confirmed, and explicit rollout switches can temporarily disable it.

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Free to create, no setup fee. Fund your prepaid wallet through hosted Stripe Checkout; only real send orders debit it.

Evaluate the workflow

Physical-mail implementation and provider guides

Choose one decision axis: registered evidence, approval, sandbox and budgets, destination support, or a provider migration. Every guide links back to the canonical safe-send workflow.

How do I connect the MCP server for physical mail

To connect FrankKi MCP, the MCP server for physical mail, you add the remote server https://mcp.frankki.app to your MCP client and authenticate with a scoped Bearer API key. The server is live and speaks streamable HTTP, so any compliant assistant such as ChatGPT, Claude, Cursor or VS Code can call its 64 model-visible tools to draft, price and send real letters worldwide. The official MCP Registry name is app.frankki/letters.

https://mcp.frankki.app

Streamable HTTP transport. Under the hood every request is a POST to /api/mcp/v1.

Connect procedure

1When registration is available, create your account at frankki.app/dashboard/registrieren. The source flow needs no manual account approval; you receive an email link to set your password.
2Open your MCP client (ChatGPT, Claude, Cursor or VS Code) and add a remote MCP server.
3Paste the endpoint https://mcp.frankki.app as the server URL.
4Set the Authorization header to your scoped Bearer API key.
5Call letter_create_draft to build a letter, then order_send to put it in the post.

OAuth 2.1 with Authorization Code, PKCE (S256) and Dynamic Client Registration (RFC 7591) is live in production at https://mcp.frankki.app, verified 2026-08-13 against https://mcp.frankki.app/.well-known/oauth-authorization-server, alongside scoped Bearer API keys.

Which tools does the server have

FrankKi MCP exposes 64 model-visible tools (39 read-only, 25 action) split into read tools that return state and action tools that change it. Read tools such as shipping_quote, order_status and letter_list never cost money or send mail. Action tools such as letter_create_draft (free) and order_send create drafts, send letters and manage approvals. The split derives from each tool mutating flag.

Tool	Access	Purpose
Profile and wallet
`profile_get`	Read	Reads your partner profile and account data.
`wallet_balance`	Read	Shows your current wallet balance and daily cap.
`wallet_topup_link`	Read	Returns a Stripe link to top up your wallet.
`sender_profile_list`	Read	Lists your saved sender profiles.
`sender_profile_get`	Read	Reads a single sender profile in detail.
`sender_profile_validate`	Read	Checks a sender profile for mandatory details and format.
Clients
`mandant_get`	Read	Reads a single client by its ID.
`mandant_list`	Read	Lists your clients with filters and pagination.
`mandant_search`	Read	Searches clients by number, name, tag or case handler.
Templates
`template_list`	Read	Lists your letter templates with category and version.
`template_get`	Read	Reads a template including its merge fields.
`template_apply_with_merge_fields`	Read	Fills a template placeholders and returns subject and content.
`template_diff_check`	Read	Compares a letter against its template and shows the differences.
`template_save`	Action	Saves a template as a draft version.
`template_release`	Action	Releases a draft version so it becomes sendable.
`template_archive`	Action	Archives a template without deleting it.
`template_draft_discard`	Action	Discards a draft version that has not been released yet.
Letters
`letter_get`	Read	Reads a single letter with status, content and PDF link.
`letter_list`	Read	Lists your letters with filter and paging options.
`letter_search`	Read	Full-text searches your letters across subject, recipient and content.
`letter_create_draft`	Action	Creates a letter draft. Free, without sending.
`attachment_upload_pdf`	Action	Attaches a PDF to a letter draft.
`attachment_upload_image`	Action	Attaches an image to a letter draft and scales it to A4.
`shipping_quote`	Read	Calculates the price of a letter by destination country and mail type.
`pricing_tiers`	Read	Returns the volume tiers: from which monthly quantity which per-letter price applies.
`order_status`	Read	Reads the dispatch and delivery status of an order.
`order_einlieferungsbeleg`	Read	Returns the proof of posting for a sent order.
Addresses and export
`address_validate`	Read	Validates an address with the mail provider without storing it.
`address_upsert`	Action	Creates or updates an address in the address book.
`address_list`	Read	Lists the addresses in your partner address book.
`address_search_company`	Read	Searches companies and authorities in the directory with their mailing address.
`archive_export`	Read	Starts an archive export for accounting, DATEV or DMS.
`archive_export_status`	Read	Queries the status of an archive export and returns the download link.
Sending and actions
`order_send`	Action	Sends a letter by post and charges your wallet.
`order_send_batch`	Action	Sends several letters in one batch with a single approval.
`order_cancel`	Action	Cancels an order as long as it has not been printed yet.
`order_fix_resubmit`	Action	Corrects the recipient address of a rejected letter and resubmits it.
`letter_schedule`	Action	Schedules the dispatch of a draft for a later time.
`schedule_list_or_cancel`	Action	Lists scheduled sends or cancels a scheduled send.
Approvals
`approval_list`	Read	Lists open letters in the approval queue.
`approval_submit`	Action	Submits a letter for human approval.
`approval_decide`	Action	Approves a letter after explicit consent, or rejects it.
Presets and uploads
`preset_save`	Action	Saves a sending preset for recurring letters.
`signature_upload`	Action	Uploads a signature as PNG and stores it.
`signature_list`	Read	Lists your saved signatures with a preview link.
`letterhead_upload`	Action	Uploads a letterhead and stores it.
`letterhead_list`	Read	Lists your saved letterheads with a preview link.
Letter design
`letter_design_save`	Action	Saves a reusable letter design and checks the delivery clear zones.
`letter_design_list`	Read	Lists your saved letter designs.
`letter_design_preview`	Read	Renders a preview PDF of a letter design.
`letter_design_delete`	Action	Archives a letter design so it is no longer used.
Operations
`mcp_health`	Read	Checks your token and the processing chain with an echo probe.
More tools
`sender_profile_upsert`	Action	Creates or edits a sender profile: legal form, mandatory details, optionally bank details, disclaimer and default letterhead.
`analytics_summary`	Read	Returns the partner account's aggregated metrics: letters per month, cost per mandant for rebilling, transit times to delivery, failure rates, and spend against configured limits.
`setup_fix_link`	Read	Hands one item over to the human in a browser: top up the balance, sign the data processing agreement or complete the sender profile.
`letter_design_list_presets`	Read	Returns the owner-approved native-v2 letterheads as safe starting points for cancellations, invoices, payment reminders, quotes, contracts and letters to public authorities.
`brand_kit_get`	Read	Reads the saved brand values for the user-facing result letterhead and brand.
`brand_kit_save`	Action	Saves logo references, colours and font for the user-facing result letterhead and brand.
`brand_import_from_website`	Action	Reads a public company website and proposes a letterhead design from it: brand colours, a mapped house typeface, logo candidates and company details from the imprint.
`letter_preview`	Read	Preview letter and draft as images, render form preview: composes like a real send and returns inline PNGs, PDF link, page count, cost and designRender with the actual documentMode, rendered letter chrome and bodyStartMm.
`template_preview`	Read	Renders a STORED template with sample values and returns inline PNGs, PDF link and designRender.
`document_create`	Action	Turns a structured billing payload into a finished document and stores it as a letter draft: FrankKi re-computes line items, net, VAT rates and gross, checks the mandatory details under § 14 UStG, optionally draws the document number from your sequence, and typesets everything in the DIN 5008 layout with your letter design.
`document_list`	Read	Lists the documents you created (invoice, payment reminder, dunning letter, credit note), newest first, filtered by type, client, recipient or referenced document.
`document_get`	Read	Returns one document with its full payload (line items, totals, VAT rates, reference) plus the letterId and orderId of the letter it lives in.

How much does a letter cost

A standard letter via FrankKi MCP starts at 3,39 EUR in black and white or 3,49 EUR in color. With volume tiers, a German standard letter drops to 1,49 EUR from 20,000 letters per month, and many destinations are cheaper depending on volume. A registered letter (Einschreiben Einwurf) starts at 7,59 EUR, and a registered letter handed over against signature (Einschreiben Übergabe) starts at 8,19 EUR. shipping_quote returns the exact destination price before any send. MCP partners fund a prepaid wallet through a hosted Stripe Checkout page, and order_send debits that wallet. MCP never collects card data in the agent interaction. There is no subscription.

Per-letter prices with FrankKi MCP
Product	From	Detail
Standard letter	from 3,39 €	Black and white
Standard letter	from 3,49 €	Color
Volume tiers	from 1,49 €	German standard letter from 20,000 letters per month
Registered (Einwurf)	from 7,59 €	Delivery with proof of posting, no signature
Registered (Übergabe)	from 8,19 €	Handed over in person against signature

Delivery within 1 to 3 working days inside Germany.

Fixed prices across DACH (DE, AT, CH). Worldwide via local partners and DHL, quoted per destination.

What is FrankKi MCP

FrankKi MCP is the agentic layer of letters: a live remote hosted Model Context Protocol server that gives AI assistants and agents a direct interface to real postal mail. Its 64 model-visible tools draft a letter formatted to the German DIN 5008 standard, return a binding price, send it worldwide and track delivery, all without a human leaving the chat.

We built FrankKi MCP so an agent can finish the job. It does not stop at the draft, it puts the letter in the post.
FrankKi founder

Every send goes through the same fulfillment safety net as our app. MCP partners fund a prepaid wallet through hosted Stripe Checkout, and the send debits that wallet. The MCP layer is a clean interface on top of a proven pipeline.
FrankKi operations

Who is FrankKi MCP for

FrankKi MCP makes letters for AI agents a normal workflow for law firms, tax advisors, agencies and developers who want their AI tools to send real letters without manual printing. Any team that drafts correspondence in an assistant can connect once at https://mcp.frankki.app and turn a draft into a posted physical letter in the same conversation, delivered worldwide.

Law firms

Draft client and counterparty letters in your assistant and send them as registered mail with proof of posting or signature on delivery where the destination supports that service, with tracking according to the selected service level.

Tax advisors

Generate filings, reminders and authority correspondence per client, then send them straight to the post with an approval step before anything leaves the office.

Agencies

Run mailings and per client outreach from one connection, send single letters or batches with order_send_batch, and keep every dispatch tracked and auditable.

Developers

Wire FrankKi MCP into agents and pipelines over plain streamable HTTP. Draft, quote, send and track letters with 64 model-visible tools and a single scoped Bearer API key.

Letter design

Give your agent existing stationery or a logo. It rebuilds them as a FrankKi letter design, creates a real sample letter for review, and saves the result only after you have checked it.

How dispatch works with FrankKi MCP

Automated

Every letter runs automatically from the AI assistant to postal handover, with no manual printing or stuffing envelopes on your side.

An operator monitors every send today, on top of the automated pipeline. Once enough real dispatches are measured, we will add a measured delivery rate here.

How secure is the connection

FrankKi MCP authenticates calls with scoped Bearer API keys and runs each send through the same fulfillment safety net as the FrankKi app. MCP partners fund a prepaid wallet through a hosted Stripe Checkout page and send debits from that wallet. OAuth 2.1 with Authorization Code, PKCE (S256) and Dynamic Client Registration (RFC 7591) is live in production at https://mcp.frankki.app, verified 2026-08-13 against https://mcp.frankki.app/.well-known/oauth-authorization-server. Read tools never change state, action tools are explicit, and every physical dispatch requires a human decision before it is sent. It is built for regulated mail: Einschreiben (registered mail) with an Einlieferungsbeleg (proof of posting) where supported, separated Mandanten (client matters) and approval flows with a human decision before a letter leaves.

Authenticated calls

Every request carries your scoped Bearer API key, or an OAuth access token. OAuth 2.1 with Authorization Code, PKCE (S256) and Dynamic Client Registration (RFC 7591) is live in production at https://mcp.frankki.app, verified 2026-08-13 against https://mcp.frankki.app/.well-known/oauth-authorization-server.

Read and action are separate

Read tools return state and never send mail. Action tools such as order_send are explicit, so an agent cannot post a letter by accident.

Approval queue

Every physical dispatch enters the approval queue. A human uses approval_decide before the letter leaves, and every decision is logged.

Proven fulfillment

Sends run through the same fulfillment pipeline that already powers the FrankKi app. The partner wallet is funded separately through hosted Stripe Checkout and debited on send.

Frequently asked questions

How do I send a physical letter via MCP

Connect your assistant to FrankKi MCP at https://mcp.frankki.app, authenticate with your scoped Bearer API key, then call letter_create_draft to build the letter and order_send to put it in the post. FrankKi MCP prints and mails it worldwide and you track it with order_status. That is how you send mail from an AI agent today.

Is FrankKi MCP live yet

Yes. FrankKi MCP is live. Add https://mcp.frankki.app as a remote MCP server in ChatGPT, Claude, Cursor or VS Code, authenticate, and call letter_create_draft then order_send to put a real letter in the post, worldwide. Sign up yourself at frankki.app/dashboard/registrieren without manual account approval; you receive an email link to set your password.

What exactly is FrankKi MCP

FrankKi MCP is a live, remote hosted MCP server for physical mail that lets AI assistants draft, price, send and track real letters worldwide. You connect your AI client once, and from then on a single tool call puts a physically printed and delivered letter in the post. Agents and people use the same pipeline.

How do I connect FrankKi MCP

You connect FrankKi MCP by adding https://mcp.frankki.app as a remote MCP server in your AI client and setting your scoped Bearer API key as the Authorization header. The client opens a streamable HTTP connection, and all 64 model-visible tools are then available in the chat, so your agent can draft and send letters.

Which AI assistants are supported

Any MCP client that speaks streamable HTTP, including ChatGPT, Claude, Cursor and VS Code. You add https://mcp.frankki.app as a remote MCP server and set your scoped Bearer API key as the Authorization header. The same connection serves a chat assistant and an unattended agent, so people and agents share one pipeline.

How much does a letter cost

A standard letter starts at 3,39 EUR in black and white or 3,49 EUR in color. With volume tiers, a German standard letter drops to 1,49 EUR from 20,000 letters per month. A registered letter starts at 7,59 EUR (Einwurf) or 8,19 EUR handed over against signature (Übergabe). shipping_quote returns the exact destination price before any send. MCP partners top up a prepaid wallet through a hosted Stripe Checkout page, and order_send debits that wallet. MCP never collects card data in the agent interaction.

Which tools does FrankKi MCP offer

FrankKi MCP offers 64 model-visible tools, split into read and action. Read tools such as shipping_quote, order_status and letter_list fetch data without changing anything. Action tools such as letter_create_draft, order_send and approval_submit create, send or change letters and orders straight from your AI assistant.

Does drafting a letter cost anything

No, creating a draft with letter_create_draft is free. When you call order_send, the price is debited from your prepaid wallet. If the balance is too low, top it up outside the MCP chat through a hosted Stripe Checkout page. That way you can check content, recipient and layout before your AI assistant puts the letter in the post.

How secure is the connection

Every call to FrankKi MCP is authenticated with a scoped Bearer API key, read tools never change state, and every physical dispatch requires human sign-off before it is sent. OAuth 2.1 with Authorization Code, PKCE (S256) and Dynamic Client Registration (RFC 7591) is live in production at https://mcp.frankki.app, verified 2026-08-13 against https://mcp.frankki.app/.well-known/oauth-authorization-server.

Are the letters legally valid

FrankKi helps draft, format and physically send letters, but it does not determine whether a particular letter is legally sufficient or legally effective. That depends on matters such as content, authority, form, signature, recipient and deadlines. DIN 5008 governs presentation, not legal effect. Registered mail can provide the applicable posting or delivery record where the destination supports it. FrankKi does not provide legal advice.

Which countries can my agent send letters to

FrankKi MCP sends worldwide. Local postal tariffs apply across DACH (Germany, Austria, Switzerland) and several European countries, and the rest of the world is served by DHL in typically 4 to 18 business days. International prices are quoted per destination, so shipping_quote returns the exact amount before your agent sends anything.

Can I use FrankKi MCP for regulated client mail

Yes. FrankKi MCP is built for correspondence that has to hold up: registered mail with an Einlieferungsbeleg (proof of posting) or handover against signature where supported, DIN 5008 typesetting, separated Mandanten (client matters), and approval flows where a human decides before a letter leaves. You can rehearse the whole path first with dryRun: true, which runs the full validation, gates and pricing and returns a preview without printing or charging anything. Sandbox mode is a separate per-account grant that is off by default and currently unavailable; dryRun is the documented substitute.

What makes FrankKi MCP different from other letter APIs

FrankKi MCP is German and DACH native and still delivers worldwide, while most agent facing mail APIs are built around US mail and established letter APIs have no agent story at all. On top of that it carries Einschreiben with Einlieferungsbeleg, DIN 5008, Mandanten separation, approval flows, and wallet-funded sends without a subscription or card collection in the MCP chat.

Connect FrankKi MCP today

FrankKi MCP is live. Create your account, set your password through the email link, top up your prepaid wallet through the hosted Stripe Checkout page, create your scoped Bearer API key, and point your assistant at https://mcp.frankki.app to send a real letter from your AI agent, worldwide, from 3,39 EUR with no subscription. shipping_quote gives you the exact price before the send.

Create your account and start

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Free to create, no setup fee. Fund your prepaid wallet through hosted Stripe Checkout; only real send orders debit it.