# Billej
> Lej en bil på seks måneder eller mere. Fast pris om måneden med forsikring, service og grøn ejerafgift — og depositum retur, når bilen kommer hjem. Se flåden og bestil online.

## What this site is

Billej is **one Danish car-rental company renting out its own
cars**. It is not a marketplace and has no supply side: there are no
lister accounts, no categories and no third-party sellers. The company
publishes its fleet, a customer browses it, picks a car and checks out.

Facts an agent must not get wrong:

- The conversion event is a CHECKOUT, not an inquiry. The customer pays
  on this site, and a rental contract is issued as a result.
- Every rental runs for a MINIMUM OF SIX MONTHS. A per-day or per-night
  booking does not exist here; a term is measured in whole months.
- One car is one physical vehicle, identified by its registration number.
  Availability is a status on the row, not a stock count — two customers
  can never be sold the same registration.
- At checkout the customer pays the first month's rent, a refundable
  deposit and a one-off establishment fee on a single card charge. The
  deposit is CHARGED, not authorised, and refunded at settlement.
  Months 2…N are collected monthly off-session on the saved card.
- Currency is DKK, written `4.995 kr/md` and `12.400 kr`. Every amount in
  the API and the UI is WHOLE KRONER INCLUDING 25 % moms. Only the Stripe
  boundary works in øre.
- Dates are `YYYY-MM-DD` day keys resolved in `Europe/Copenhagen`, never
  instants.
- The payment schedule is DERIVED from the booking's start date, term and
  monthly price. It is never stored; only real payment attempts are.
- Languages are Danish (`da`, default) and English (`en`). Nothing else.

## Key pages

- Front page: https://www.billej.dk/
- The fleet: https://www.billej.dk/biler
- One car: https://www.billej.dk/biler/{slug}
- Checkout: https://www.billej.dk/reserver/{slug}
- Confirmation: https://www.billej.dk/kvittering/{id}
- Pricing, deposit and what a month includes: https://www.billej.dk/priser
- How it works: https://www.billej.dk/saadan-virker-det
- Guides: https://www.billej.dk/blogs
- FAQ: https://www.billej.dk/faq
- About: https://www.billej.dk/om
- Contact: https://www.billej.dk/kontakt
- Terms: https://www.billej.dk/vilkaar
- Privacy: https://www.billej.dk/privatliv

English aliases (`/cars`, `/pricing`, `/how-it-works`, `/about`,
`/contact`, `/terms`, `/privacy`) answer with a 308 to the Danish path.
Link to the Danish path directly and save the redirect hop.

## Further reading

- OpenAPI 3.1 spec (JSON): https://www.billej.dk/api/openapi.json
- Human-readable API reference: https://www.billej.dk/to-humans.md
- Interactive API docs: https://www.billej.dk/api/docs

---
# Billej API
> Browse the fleet, price a rental, and reserve a car. Billej lets its own cars on agreements of at least six months.

## Authentication
Session-based via cookie `better-auth.session_token`.
Sign in: POST /api/auth/sign-in/email { email, password }
Endpoints marked [public] do not require authentication.

## Guides

### GET /api/blogs
Retrieve a list of Guides [public]

Parameters:
  page (number, query, optional): 
  limit (number, query, optional): 
  depth (number, query, optional): 
  locale (string, query, optional): 
  fallback-locale (string, query, optional): 
  sort (string, query, optional): 
  where (string, query, optional): 

Responses:
  200: List of Guides

### GET /api/blogs/{id}
Find a Guide by ID [public]

Responses:
  200: Guide object
  404: Guide not found

## FAQs

### GET /api/faqs
Retrieve a list of FAQs [public]

Parameters:
  page (number, query, optional): 
  limit (number, query, optional): 
  depth (number, query, optional): 
  locale (string, query, optional): 
  fallback-locale (string, query, optional): 
  sort (string, query, optional): 
  where (string, query, optional): 

Responses:
  200: List of FAQs

### GET /api/faqs/{id}
Find a FAQ by ID [public]

Responses:
  200: FAQ object
  404: FAQ not found

## Media

### GET /api/media
Retrieve a list of Media [public]

Parameters:
  page (number, query, optional): 
  limit (number, query, optional): 
  depth (number, query, optional): 
  locale (string, query, optional): 
  fallback-locale (string, query, optional): 
  sort (string, query, optional): 
  where (string, query, optional): 

Responses:
  200: List of Media

### GET /api/media/{id}
Find a Media by ID [public]

Responses:
  200: Media object
  404: Media not found

## addresses

### GET /api/addresses
Retrieve a list of addresses [auth required]

Parameters:
  page (number, query, optional): 
  limit (number, query, optional): 
  depth (number, query, optional): 
  locale (string, query, optional): 
  fallback-locale (string, query, optional): 
  sort (string, query, optional): 
  where (string, query, optional): 

Responses:
  200: List of addresses

### POST /api/addresses
Create a new addresses [auth required]

Parameters:
  depth (number, query, optional): 
  locale (string, query, optional): 

Request body (JSON):
  customer: string (optional) — ID of the users
  title: string | null (optional)
  firstName: string | null (optional)
  lastName: string | null (optional)
  company: string | null (optional)
  addressLine1: string | null (optional)
  addressLine2: string | null (optional)
  city: string | null (optional)
  state: string | null (optional)
  postalCode: string | null (optional)
  country: string [enum: US, GB, CA, AU, AT, BE, BR, BG, CY, CZ, DK, EE, FI, FR, DE, GR, HK, HU, IN, IE, IT, JP, LV, LT, LU, MY, MT, MX, NL, NZ, NO, PL, PT, RO, SG, SK, SI, ES, SE, CH] (required)
  phone: string | null (optional)

Responses:
  201: addresses object

### GET /api/addresses/{id}
Find a addresses by ID [auth required]

Responses:
  200: addresses object
  404: addresses not found

### PATCH /api/addresses/{id}
Update a addresses [auth required]

Request body (JSON):
  customer: string (optional) — ID of the users
  title: string | null (optional)
  firstName: string | null (optional)
  lastName: string | null (optional)
  company: string | null (optional)
  addressLine1: string | null (optional)
  addressLine2: string | null (optional)
  city: string | null (optional)
  state: string | null (optional)
  postalCode: string | null (optional)
  country: string [enum: US, GB, CA, AU, AT, BE, BR, BG, CY, CZ, DK, EE, FI, FR, DE, GR, HK, HU, IN, IE, IT, JP, LV, LT, LU, MY, MT, MX, NL, NZ, NO, PL, PT, RO, SG, SK, SI, ES, SE, CH] (optional)
  phone: string | null (optional)

Responses:
  200: addresses object
  404: addresses not found

### DELETE /api/addresses/{id}
Delete a addresses [auth required]

Responses:
  200: addresses object
  404: addresses not found

## variants

### GET /api/variants
Retrieve a list of variants [public]

Parameters:
  page (number, query, optional): 
  limit (number, query, optional): 
  depth (number, query, optional): 
  locale (string, query, optional): 
  fallback-locale (string, query, optional): 
  sort (string, query, optional): 
  where (string, query, optional): 

Responses:
  200: List of variants

### GET /api/variants/{id}
Find a variants by ID [public]

Responses:
  200: variants object
  404: variants not found

## variantTypes

### GET /api/variantTypes
Retrieve a list of variantTypes [public]

Parameters:
  page (number, query, optional): 
  limit (number, query, optional): 
  depth (number, query, optional): 
  locale (string, query, optional): 
  fallback-locale (string, query, optional): 
  sort (string, query, optional): 
  where (string, query, optional): 

Responses:
  200: List of variantTypes

### GET /api/variantTypes/{id}
Find a variantTypes by ID [public]

Responses:
  200: variantTypes object
  404: variantTypes not found

## variantOptions

### GET /api/variantOptions
Retrieve a list of variantOptions [public]

Parameters:
  page (number, query, optional): 
  limit (number, query, optional): 
  depth (number, query, optional): 
  locale (string, query, optional): 
  fallback-locale (string, query, optional): 
  sort (string, query, optional): 
  where (string, query, optional): 

Responses:
  200: List of variantOptions

### GET /api/variantOptions/{id}
Find a variantOptions by ID [public]

Responses:
  200: variantOptions object
  404: variantOptions not found

## products

### GET /api/products
Retrieve a list of products [public]

Parameters:
  page (number, query, optional): 
  limit (number, query, optional): 
  depth (number, query, optional): 
  locale (string, query, optional): 
  fallback-locale (string, query, optional): 
  sort (string, query, optional): 
  where (string, query, optional): 

Responses:
  200: List of products

### GET /api/products/{id}
Find a products by ID [public]

Responses:
  200: products object
  404: products not found

## carts

### GET /api/carts
Retrieve a list of carts [auth required]

Parameters:
  page (number, query, optional): 
  limit (number, query, optional): 
  depth (number, query, optional): 
  locale (string, query, optional): 
  fallback-locale (string, query, optional): 
  sort (string, query, optional): 
  where (string, query, optional): 

Responses:
  200: List of carts

### POST /api/carts
Create a new carts [auth required]

Parameters:
  depth (number, query, optional): 
  locale (string, query, optional): 

Request body (JSON):
  items: array | null (optional)
  secret: string | null (optional)
  customer: string (optional) — ID of the users
  purchasedAt: string | null (optional)
  status: string | null [enum: active, purchased, abandoned] (optional)
  subtotal: number | null (optional)
  currency: string | null [enum: USD] (optional)
  discountCode: string | null (optional) — Applied discount code for this cart

Responses:
  201: carts object

### GET /api/carts/{id}
Find a carts by ID [auth required]

Responses:
  200: carts object
  404: carts not found

### PATCH /api/carts/{id}
Update a carts [auth required]

Request body (JSON):
  items: array | null (optional)
  secret: string | null (optional)
  customer: string (optional) — ID of the users
  purchasedAt: string | null (optional)
  status: string | null [enum: active, purchased, abandoned] (optional)
  subtotal: number | null (optional)
  currency: string | null [enum: USD] (optional)
  discountCode: string | null (optional) — Applied discount code for this cart

Responses:
  200: carts object
  404: carts not found

### DELETE /api/carts/{id}
Delete a carts [auth required]

Responses:
  200: carts object
  404: carts not found

## Orders

### GET /api/orders
List the authenticated user's orders [auth required]

Returns a paginated list of orders belonging to the authenticated user. Orders are matched by the internal user ID or the user's email and are sorted by creation date (newest first).

Parameters:
  page (integer, query, optional): Page number for pagination (defaults to 1)
  limit (integer, query, optional): Number of orders per page (defaults to 10, max 50)

Responses:
  200: Paginated order list
  401: Not authenticated
  500: Internal server error

## orders

### GET /api/orders/{id}
Find a orders by ID [auth required]

Responses:
  200: orders object
  404: orders not found

## Contact

### POST /api/contact
Submit contact form [public]

Accepts a contact form submission and stores it in the Payload CMS `contact-form-submissions` collection. No authentication is required.

Request body (JSON):
  name: string [min: 1, max: 150, pattern: ^[\p{L}\p{N}\s\-'.]+$] (required) — Full name of the person submitting the form (e.g. "Jane Doe")
  email: string [min: 5, max: 320, format: email] (required) — Contact email address (e.g. "jane@example.com")
  subject: string [min: 1, max: 200] (required) — Subject line for the contact message (e.g. "Partnership inquiry")
  message: string [min: 1, max: 5000] (required) — Body of the contact message (e.g. "Hi, I would love to discuss a potential partnership. Please let me know a good time to connect.")

Responses:
  201: Contact form submitted successfully
  400: Validation error — missing or invalid fields
  500: Internal server error

Dashboard: Payload Admin > Contact Form Submissions

## Newsletter

### POST /api/newsletter
Subscribe to newsletter [public]

Subscribes an email address to the newsletter. The address is stored in the Payload CMS `newsletter-subscribers` collection and optionally synced to a Resend audience when `RESEND_API_KEY` and `RESEND_AUDIENCE_ID` are configured. Duplicate emails are silently ignored.

Request body (JSON):
  email: string [min: 5, max: 320, format: email] (required) — Email address to subscribe to the newsletter (e.g. "subscriber@example.com")

Responses:
  200: Successfully subscribed (or already subscribed)
  400: Validation error — invalid email address
  500: Internal server error

Dashboard: Payload Admin > Newsletter Subscribers

## Cart

### POST /api/cart/apply-discount
Apply a discount code to a cart [auth required]

Validates and applies a discount code to a basket of boosts and plans. The caller must own the cart (via session) or supply the cart secret. Amounts are DKK øre — 14900 is 149,00 kr.

Request body (JSON):
  code: string [min: 1, max: 50] (required) — The discount code to apply to the cart (e.g. "SOMMER20")
  cartId: integer [min: 1, max: 2147483647] (required) — The ID of the cart to apply the discount to (e.g. 42)
  secret: string [min: 1, max: 255] (optional) — Cart secret for guest users who are not authenticated but own the cart (e.g. "a1b2c3d4-e5f6-7890-abcd-ef1234567890")

Responses:
  200: Discount applied successfully
  400: Malformed request body, or a discount code that does not apply. The two are distinguishable: a rejected code carries `success: false`, a malformed body carries `details`.
  403: Not authorised to modify this cart
  404: Cart not found or already purchased
  500: Internal server error

Dashboard: Use from the basket or /checkout by entering a discount code and pressing Apply.

### POST /api/cart/remove-discount
Remove a discount code from a cart [auth required]

Removes any previously applied discount code from a basket of boosts and plans. The caller must own the cart (via session) or supply the cart secret.

Request body (JSON):
  cartId: integer [min: 1, max: 2147483647] (required) — The ID of the cart to remove the discount from (e.g. 42)
  secret: string [min: 1, max: 255] (optional) — Cart secret for guest users who are not authenticated but own the cart (e.g. "a1b2c3d4-e5f6-7890-abcd-ef1234567890")

Responses:
  200: Discount removed successfully
  400: Missing or invalid cart ID
  403: Not authorised to modify this cart
  404: Cart not found or already purchased
  500: Internal server error

Dashboard: Use from the basket or /checkout by clicking the remove button next to the applied code.

## Discounts

### POST /api/discount/validate
Validate a discount code [public]

Validates a discount code for a boost or plan purchase: it must exist, be active, sit inside its valid date range, be under its usage limits and meet the minimum order amount. Optionally calculates the discount when a subtotal is supplied. All amounts are DKK øre — 14900 is 149,00 kr. Rate limited to 10 requests per IP per minute.

Request body (JSON):
  code: string [min: 1, max: 50] (required) — The discount code to validate (e.g. "VELKOMMEN10")
  customerEmail: string [min: 3, max: 320, format: email] (optional) — Customer email for per-customer usage limit checks (e.g. "mette@eksempel.dk")
  subtotal: integer [min: 0, max: 99999999] (optional) — Cart subtotal in DKK øre for the minimum-order check and discount calculation (e.g. 14900)

Responses:
  200: Validation result. Both valid and invalid codes return 200; check the `valid` field.
  400: Missing or invalid request body
  429: Rate limit exceeded (10 requests per minute per IP)
  500: Internal server error

Rate limit: 10 requests per 60s

## Payments

### POST /api/payment-amount
Calculate final payment amount with optional discount [auth required]

Retrieves the current amount of a Stripe PaymentIntent for a boost or plan purchase and optionally applies a discount code. Every amount is DKK øre — 14900 is 149,00 kr. The PaymentIntent must still be in the `requires_payment_method` status. For authenticated users, ownership is verified via the Stripe customer. For guests, the PaymentIntent ID acts as authorization. Rate limited to 20 requests per IP per minute.

Request body (JSON):
  paymentIntentId: string [min: 1, max: 255] (required) — The Stripe PaymentIntent ID (e.g. "pi_3Oc0X2Abc123def456")
  discountCode: string [min: 1, max: 50] (optional) — Optional discount code to apply to the payment (e.g. "SOMMER20")

Responses:
  200: Payment amount calculated successfully
  400: Missing paymentIntentId, invalid payment state, or discount error
  403: PaymentIntent does not belong to the authenticated user
  429: Rate limit exceeded (20 requests per minute per IP)
  500: Internal server error

Rate limit: 20 requests per 60s

## Documentation

### GET /api/openapi.json
OpenAPI 3.1 specification (JSON) [public]

Returns this API's full OpenAPI 3.1 specification as JSON. Use this to generate client SDKs, import into API tools (Postman, Insomnia), or power interactive documentation UIs.

Responses:
  200: OpenAPI 3.1 JSON specification

### GET /llms.txt
LLM-friendly API reference (plain text) [public]

Returns the full API reference as structured plain text optimized for LLM context windows. Use this to feed API documentation into AI assistants, chatbots, or code generators.

Responses:
  200: Plain-text API reference

### GET /to-humans.md
Human-readable API reference (Markdown) [public]

Returns the full API reference as a Markdown document with table of contents, request/response tables, cURL examples, and error reference. Suitable for rendering in documentation sites or reading directly.

Responses:
  200: Markdown API reference