Kundenschreiber De Kundenschreiber Public API
65
AI ReadinessAI-Aware (B)65/100
Agent-ready OpenAPI document · curated by JenticMarketingMarketing AutomationapiKey33 EndpointsREST
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For Agents
Send handwritten letters and postcards via Kundenschreiber: create orders, manage senders and recipients, run trackable QR campaigns, and check shipment credits.
Use for: I need to send a handwritten letter through Kundenschreiber, I want to check my Kundenschreiber shipment credit balance, List all letter templates available in my account, Create a QR campaign to track responses to a postcard run
Not supported: Does not handle email delivery, SMS, or shipping logistics - use for handwritten letter and postcard direct mail only.
Jentic publishes the only available OpenAPI specification for Kundenschreiber Public API, keeping it validated and agent-ready. Kundenschreiber is a German handwritten-letter and postcard service whose API lets businesses create direct-mail orders, manage senders and recipients, run QR campaigns with trackable codes, and enrich company data before mailing. Authentication is an X-API-Key header. Endpoints cover the full direct-mail workflow from credit-balance checks to template selection, signature variations, and order placement.
Install Jentic One Beta
Connect the Kundenschreiber Public API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Kundenschreiber Public API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fkundenschreiber.de%2Fkundenschreiber" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fkundenschreiber.de%2Fkundenschreiber" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Kundenschreiber Public API.
Place handwritten-letter and postcard orders via POST /orders against pre-built templates from /templates
Check available shipment credit before sending via GET /shipment-balance to avoid failed dispatch
Run trackable direct-mail QR campaigns through /qr/campaigns and /qr/codes for response attribution
Manage sender and recipient address books via /senders and /recipients with create, update, and delete
Handle signature variations through /signatures so different campaigns sign with different handwriting samples
Enrich a recipient's company data via POST /enrich-company before personalising letter content
Use Cases
Patterns agents use Kundenschreiber Public API for, with concrete tasks.
★ Automated Customer Win-Back Letters
Trigger handwritten letters to lapsed customers as part of a churn-recovery flow. After a CRM identifies a churn-risk segment, an agent uploads the recipient list to /recipients, picks a win-back template via /templates, and POSTs the order to /orders. /shipment-balance is checked first so the run doesn't fail mid-batch.
GET /shipment-balance, GET /templates to pick the 'win-back' template, POST 50 recipients to /recipients, then POST /orders referencing the template and recipient IDs.
QR-Tracked Postcard Campaigns
Run a postcard campaign with QR codes that link each recipient to a tracked landing page. POST /qr/campaigns creates the campaign, POST /qr/codes generates per-recipient codes, and the postcard order references those codes so recipients scanning the postcard are attributed to the campaign in analytics.
POST /qr/campaigns with a campaign name, generate one QR code per recipient via /qr/codes, and submit a postcard order to /orders with the QR codes embedded.
Multi-Signature Brand Templates
Maintain different signature variations for different sales reps so handwritten letters carry the right rep's signature. /signatures lists existing variations, PATCH /signatures/{id} updates them, and orders pick the right signature at send time. This keeps personalisation high without re-creating templates.
GET /signatures, pick the rep's variation, and POST /orders with the chosen signature ID for each recipient.
AI Agent Direct-Mail Concierge
An assistant in a sales-ops chat receives instructions like 'send a handwritten thank-you to every closed-won deal this week' and runs the full Kundenschreiber order through Jentic. Search-by-intent finds the right operation, schemas are loaded automatically, and the X-API-Key never leaves the vault.
On 'thank every closed-won deal this week', resolve recipient list from CRM, search Jentic for 'create Kundenschreiber order', and POST /orders with the thank-you template ID.
Key Endpoints
33 endpoints — jentic publishes the only available openapi specification for kundenschreiber public api, keeping it validated and agent-ready.
METHOD
PATH
DESCRIPTION
POST
/orders
Create a handwritten letter or postcard order
GET
/shipment-balance
Check shipment credit balance
GET
/templates
List letter templates
POST
/qr/campaigns
Create a trackable QR campaign
POST
/recipients
Add a recipient to the address book
POST
/enrich-company
Enrich company data before mailing
POST
/orders
Create a handwritten letter or postcard order
GET
/shipment-balance
Check shipment credit balance
GET
/templates
List letter templates
POST
/qr/campaigns
Create a trackable QR campaign
POST
/recipients
Add a recipient to the address book
POST
/enrich-company
Enrich company data before mailing
Jentic AI Readiness Score
This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.
K
Kundenschreiber Public API
- AI-Aware (B)65/100
99
Foundational Compliance58
Developer Experience & Jentic Compatibility50
AI-Readiness & Agent Experience94
Agent Usability50
Security68
AI DiscoverabilityPowered by JenticScoring Framework 1.0.0 | Scoring Engine 0.4.0
Show dimension breakdown
99
Foundational Compliance
Base layer of spec validity and structural soundness.
Grade: A+Signals: 4
98%
Lint Results
Aggregated quality score from linter diagnostics, weighted by severity.
100%
Resolution Completeness
Percentage of `$ref` references that resolve successfully.
100%
Specification Validity
Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).
100%
Structural Integrity
Structural correctness score based on schema issues using logarithmic dampening.
58
Developer Experience & Jentic Compatibility
Clarity, completeness, and ingestion readiness for developers and tooling.
Grade: C+Signals: 4
2%
Example Density
How richly the API is illustrated with examples.
100%
Example Validity
Percentage of examples that conform to their schemas.
30%
Response Coverage
Percentage of operations with complete response definitions (success, client error, server error).
100%
Tooling Readiness
Health of API ingestion, bundling, and resolution within Jentic pipelines.
50
AI-Readiness & Agent Experience
Semantic breadth, depth, and agent comprehension for AI systems.
Grade: C-Signals: 4
38%
Description Coverage
Coverage of descriptions across API elements.
0%
Error Standardization
Coverage of RFC 9457 Problem Details for error responses.
100%
OperationId Quality
Coverage, uniqueness, and casing consistency of operationIds for AI inference.
63%
Summary Coverage
Coverage of summaries across operations/tags/info.
94
Agent Usability
Functional utility, complexity comfort, and AI orchestration readiness.
Grade: A+Signals: 1
94%
Complexity Comfort
Agent comfort level based on API operational and structural complexity.
50
Security
Trust, risk posture, and security compliance.
Grade: C-Signals: 1
50%
Authentication Strength
Average quality of security schemes based on authentication method strength (weakest link for OAuth2).
68
AI Discoverability
Findability, semantic richness, and reasoning readiness.
Grade: B+Signals: 1
68%
Descriptive Richness
Clarity and depth of descriptions across API elements.
Score it yourself
Every API in the directory is allowlisted, so you can re-score it with no key required.
npx @jentic/api-scorecard-cli score <openapi-url>Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring the Kundenschreiber Public API by hand means passing X-API-Key on every call to api.kundenschreiber.de and mapping the order, recipient, and campaign request bodies yourself. Through Jentic you install once, import the Kundenschreiber Public API from the API Directory, store the key once, and your agent calls it.
Permission scoping
Kundenschreiber's operations take their targets in the request body rather than the URL path, so scope the agent to the operations it needs, such as reading templates and shipment balance. You choose that set, so placing an order or creating a QR campaign is not included unless you add it.
Credential isolation
Your Kundenschreiber X-API-Key is stored once, encrypted, by your own Jentic One instance and injected into the header at execution time. It never enters the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'send a handwritten letter' or 'create a QR campaign', 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
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Kundenschreiber Public API through Jentic.
Why is there no official OpenAPI spec for Kundenschreiber Public API?
Kundenschreiber does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call Kundenschreiber Public API via structured tooling. It is validated against the live API and kept up to date. Get started with Jentic One, the self-hosted execution layer.
What authentication does the Kundenschreiber Public API use?
Kundenschreiber uses an API key passed in the X-API-Key header. Through Jentic, the API key is stored encrypted in your Jentic One instance and injected at request time so the agent never holds the raw secret.
Can I send a handwritten letter to a recipient with the Kundenschreiber API?
Yes. POST /orders creates a handwritten letter or postcard order against a template ID from /templates and a recipient ID from /recipients. Check /shipment-balance first to confirm the account has credits for the run.
How do I run a QR-tracked direct-mail campaign through Jentic?
Search Jentic for 'create a Kundenschreiber QR campaign'. Jentic returns POST /qr/campaigns and POST /qr/codes. Generate one code per recipient, then POST /orders with the codes referenced on each piece.
What are the rate limits for the Kundenschreiber Public API?
Specific rate limits are not exposed in the public OpenAPI spec. Contact support@kundenschreiber.de to confirm per-account limits before scheduling large batches.
Can I enrich company data before sending a letter?
Yes. POST /enrich-company augments a company record before personalisation, so letters can address recipients by their current company details. Use this before constructing the order body.
Can I limit what my agent is allowed to do with the Kundenschreiber Public API?
Yes. Because you run Jentic One yourself, your own rules decide which Kundenschreiber operations and credentials the agent may use. Kundenschreiber's operations take their targets in the request body rather than the URL path, so you scope the agent to just the operations it needs, such as reading templates via /templates and checking credit via /shipment-balance. Placing an order through POST /orders or creating a campaign through POST /qr/campaigns is not available to the agent unless you add it to that set.
GET STARTED