> ## Documentation Index > Fetch the complete documentation index at: https://docs.deepcontext.app/llms.txt > Use this file to discover all available pages before exploring further. # Get open start times > Free start times for one service over a window of up to 62 days. Returns bookable start times as UTC instants. Minimum notice, booking horizon, appointment duration, trailing buffers, and DST transitions are already applied, so every instant returned was bookable at the moment it was computed. The response never contains booking rows, customer data, or explicit busy ranges. `slots` is the entire payload by design — a busy-range response would leak the tenant's calendar to anyone with a slug. **Availability is advisory; the submit is authoritative.** Another customer can take a slot between this read and your write, which comes back as `409 booking_conflict`. Responses are cached 5s in the browser and 15s in the shared cache, so a plain refetch straight after a conflict can hand you back the slot you just lost. Append a cache-buster (`&_=${Date.now()}`) when you refetch after a `409`. ## Grouping into local days is your job `slots` are instants; `timezone` is the tenant's IANA zone. Rendering "Tuesday" correctly — and surviving DST — means bucketing in that zone, not the visitor's: ```js theme={null} function groupSlotsByDate(slots, timeZone) { const byDate = new Map(); for (const slot of slots) { // en-CA renders YYYY-MM-DD. const key = new Intl.DateTimeFormat("en-CA", { timeZone, year: "numeric", month: "2-digit", day: "2-digit", }).format(new Date(slot)); byDate.set(key, [...(byDate.get(key) ?? []), slot]); } return byDate; } ``` ## Window rules `from` is inclusive, `to` is exclusive, both must be ISO-8601 **with an offset**, and the window may span at most 62 days. A wider window is `400 window_too_large` — page through it instead. The hosted page requests 60 days, comfortably inside the cap. ## OpenAPI ````yaml openapi.json GET /api/public/tenants/{slug}/availability openapi: 3.1.0 info: title: DPC Bookings API version: 1.0.0 description: >- Public, unauthenticated endpoints for taking a booking from a custom website. Read services, read open times, submit one booking. Booking management lives in the DPC dashboard. servers: - url: https://deepcontext.app security: [] paths: /api/public/tenants/{slug}/availability: get: summary: Get open start times description: >- Free start times only — never bookings, customer data, or busy ranges. Minimum notice, booking horizon, duration, trailing buffers, and DST are already applied. Availability is advisory; the submit is authoritative. Another customer can take a slot between this read and your write, which is a `409 booking_conflict`. Responses are cached 15s in the shared cache, so add a cache-buster when you refetch after a conflict. operationId: getBookingAvailability parameters: - name: slug in: path required: true description: >- The tenant's public booking slug. Issued by DPC; there is no discovery endpoint. schema: type: string - name: service_id in: query required: true description: Duration and buffers are taken from this service. schema: type: string format: uuid pattern: >- ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$ - name: from in: query required: true description: Inclusive window start. ISO-8601 with an offset. schema: type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d(?::[0-5]\d(?:\.\d+)?)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ - name: to in: query required: true description: >- Exclusive window end. ISO-8601 with an offset. At most 62 days after `from`. schema: type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d(?::[0-5]\d(?:\.\d+)?)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$ responses: '200': description: Open start times as UTC instants content: application/json: schema: type: object properties: service_id: type: string format: uuid pattern: >- ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$ from: type: string to: type: string timezone: type: string slots: type: array items: type: string required: - service_id - from - to - timezone - slots additionalProperties: false '400': description: Invalid query, window too large, or unknown/inactive service content: application/json: schema: type: object properties: error: type: object properties: code: type: string message: type: string required: - code - message additionalProperties: false required: - error additionalProperties: false '404': description: Unknown slug, or the tenant has booking disabled content: application/json: schema: type: object properties: error: type: object properties: code: type: string message: type: string required: - code - message additionalProperties: false required: - error additionalProperties: false ````