canonical: https://jentic.com/apis/api.kundenschreiber.de/kundenschreiber # Kundenschreiber De Kundenschreiber Public API Jentic publishes the only available OpenAPI specification for the Kundenschreiber Public API, keeping it validated and agent-ready. The Kundenschreiber Public API creates and sends handwritten letters and postcards, managing the orders, templates, senders, and recipients behind each mailing. It also runs QR code campaigns and funnels, stores reusable signatures, enriches company records, and reports the remaining shipment credit balance. ## For AI agents Create and send handwritten letters and postcards, managing orders, templates, senders, and recipients. Run QR code campaigns and funnels, and check the remaining shipment credit balance. ## Scope Does not handle email delivery, payment processing, or address verification. Use for handwritten letter and postcard mailings only. ## Capabilities - Create and list mailing orders for handwritten letters and postcards - List letter, postcard, and envelope templates available for an order - Manage senders and recipients used across mailings - Create and update QR code campaigns and the codes within them - List funnels and manage reusable signatures with their variations - Check the remaining shipment credit balance and enrich company records ## Use cases ### Automated Direct Mail Agent An AI agent turns a triggering event, such as a new signup or a churn risk, into a physical mailing. It selects a template, resolves the sender and recipient, and creates the order through Kundenschreiber. Through Jentic the agent discovers the order and template operations by intent and calls them directly, so a handwritten touchpoint goes out without manual work. Example prompt: Create an order that sends a handwritten welcome letter to a new customer using a chosen template ### QR Campaign Management Attach trackable QR codes to printed mailings so response can be measured. The agent creates a campaign, generates codes, and updates them as the campaign runs. This ties physical mail back to digital funnels without leaving the API. Example prompt: Create a QR campaign and generate a code to print on an upcoming postcard mailing ### Recipient and Sender Management Keep the address book behind mailings current by adding recipients, updating sender details, and removing entries that are no longer used. This lets an agent prepare a clean recipient list before an order is created, so mailings reach the right addresses. Example prompt: Add a new recipient and confirm the sender details before creating a mailing order ## Key endpoints | Method | Path | Description | | --- | --- | --- | | POST | `/orders` | Create a mailing order | | GET | `/orders/{id}` | Get order details | | GET | `/templates` | List letter and postcard templates | | POST | `/qr/campaigns` | Create a QR code campaign | | GET | `/shipment-balance` | Get shipment credit balance | ## Key resources - **Orders and templates** — Create mailing orders and list the letter, postcard, and envelope templates - **Senders and recipients** — Manage the sender and recipient records used across mailings - **QR campaigns and funnels** — Run QR code campaigns and codes and list marketing funnels ## Why Jentic - **Setup:** Wiring the Kundenschreiber API by hand means handling its X-API-Key auth, resolving senders, recipients, and templates, and posting orders yourself. Through Jentic you install once, import Kundenschreiber from the API Directory, store the key once, and your agent calls it. - **Permission scoping:** Kundenschreiber identifies orders, senders, and recipients by an id in the request path, so a rule bounds which operations your agent may call. You choose those operations, so destructive ones like deleting a sender or recipient are not included unless you add them. - **Credential handling:** Your Kundenschreiber API key is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context. - **Discovery method:** Agents search Jentic by intent such as 'send a handwritten letter' or 'create a mailing order', and Jentic returns the matching Kundenschreiber operation with its input schema so the agent calls the right endpoint without browsing the reference docs. ## Related APIs - **Click2Mail** — Print-and-mail API compared with Kundenschreiber's handwritten mailings - **Mailchimp** — Email marketing that pairs with Kundenschreiber's physical mailings - **SendGrid** — Transactional email alongside Kundenschreiber's printed mail ## FAQ ### What authentication does the Kundenschreiber Public API use? The Kundenschreiber Public API authenticates with an API key sent in the X-API-Key header, per its OpenAPI spec. Through Jentic the key is stored encrypted by your own Jentic One instance and injected at call time, so it never enters the agent's prompt or logs. ### Can I send a handwritten letter with the Kundenschreiber Public API? Yes. Choose a template, resolve the sender and recipient, and create the mailing with POST /orders. GET /templates lists the letter and postcard templates you can use, and GET /shipment-balance shows the credit remaining. ### What are the rate limits for the Kundenschreiber Public API? The OpenAPI spec does not specify rate limits. Check the Kundenschreiber documentation at https://api.kundenschreiber.de before running high-volume mailing jobs. ### Why is there no official OpenAPI spec for the Kundenschreiber Public API? Kundenschreiber does not publish its own OpenAPI description. Jentic maintains this specification from the documented endpoints and keeps it validated so agents can call the API reliably. ### Is there a Kundenschreiber MCP server? You don't need an MCP server to give your agent the Kundenschreiber API. Jentic connects it directly from the API Directory: import it, store your key once, and your agent calls the order and template operations it needs. ### Can I limit what my agent is allowed to do with the Kundenschreiber Public API? Yes. Write a rule that allows only the order and template operations, so the agent can prepare and send mailings but cannot delete senders or recipients, and every call it makes is logged. ### How do I send a mailing with the Kundenschreiber Public API through Jentic? Search Jentic for 'send a handwritten letter', and it returns the POST /orders and GET /templates operations with their input schemas so your agent creates the mailing directly. To run it on your own infrastructure, install Jentic One from its GitHub repo.