> ## Documentation Index > Fetch the complete documentation index at: https://docs.needalert.app/llms.txt > Use this file to discover all available pages before exploring further. # Preview an alert > What sending this item's alert right now would cost: eligible subscribers, credits (one per person), the chain's balance and whether it covers the send. Nothing is sent or charged. `schedule` gives the window `scheduled_at` accepts and the lead of the low-balance warning. ## OpenAPI ````yaml /api-reference/openapi.json get /establishments/{establishment}/items/{item}/dispatch-preview openapi: 3.1.0 info: title: Need Alert API version: '1' description: >- The Need Alert API lets your own system — an ERP, an online store, a clinic's scheduling software — do what the panel does, without anyone at the screen: keep items in sync, read who is waiting, estimate the cost of an alert, send or schedule it, and follow your credit balance. Authenticate every request with an API key created by the chain owner in the panel (**Integrações**), sent as `Authorization: Bearer `. Always send `Accept: application/json`. Send `Idempotency-Key` on the two creating endpoints so a retry never creates an item or alerts the subscribers twice. Guides, in Portuguese and English: https://need-alert.mintlify.app/api/overview servers: - url: https://needalert.app/api/v1 description: Production security: - apiKey: [] tags: - name: Establishments - name: Items - name: Dispatches - name: Credits paths: /establishments/{establishment}/items/{item}/dispatch-preview: get: tags: - Dispatches summary: Preview an alert description: >- What sending this item's alert right now would cost: eligible subscribers, credits (one per person), the chain's balance and whether it covers the send. Nothing is sent or charged. `schedule` gives the window `scheduled_at` accepts and the lead of the low-balance warning. operationId: v1.establishments.items.dispatch-preview parameters: - name: establishment in: path required: true description: The establishment ID schema: type: integer - name: item in: path required: true description: The item ID schema: type: integer - name: Accept-Language in: header description: >- Language of `message` and of translated content such as item names (`pt-BR` or `en`). Without it, the chain's default language. schema: type: string enum: - pt-BR - en example: pt-BR - name: X-Request-Id in: header description: >- Your own correlation id (1–64 characters of `A-Za-z0-9._-`), echoed back; generated when absent. Quote it to support. schema: type: string pattern: ^[A-Za-z0-9._-]{1,64}$ minLength: 1 maxLength: 64 responses: '200': description: '`DispatchPreview`' content: application/json: schema: type: object properties: data: $ref: '#/components/schemas/DispatchPreview' required: - data headers: Content-Language: description: The language of the body, BCP 47 (`pt-BR`, `en`). schema: type: string X-Request-Id: description: The request id, yours or the one generated here. schema: type: string '401': description: '- `unauthenticated`: Missing, malformed, expired or revoked API key.' content: application/json: schema: allOf: - $ref: '#/components/schemas/ErrorEnvelope' - type: object properties: code: type: string enum: - unauthenticated headers: Content-Language: description: The language of the body, BCP 47 (`pt-BR`, `en`). schema: type: string X-Request-Id: description: The request id, yours or the one generated here. schema: type: string '403': description: >- - `establishment_unavailable`: The unit is inactive or suspended. - `forbidden`: The key lacks the permission this operation needs in this unit (`view`, `create_items`, `edit_items`, `dispatch_events` or `manage_billing`). - `tenant_suspended`: The chain that owns the key is suspended. content: application/json: schema: allOf: - $ref: '#/components/schemas/ErrorEnvelope' - type: object properties: code: type: string enum: - establishment_unavailable - forbidden - tenant_suspended headers: Content-Language: description: The language of the body, BCP 47 (`pt-BR`, `en`). schema: type: string X-Request-Id: description: The request id, yours or the one generated here. schema: type: string '404': description: >- - `not_found`: No such resource, or it is outside the key's scope. The API never reveals whether a resource you cannot see exists. content: application/json: schema: allOf: - $ref: '#/components/schemas/ErrorEnvelope' - type: object properties: code: type: string enum: - not_found headers: Content-Language: description: The language of the body, BCP 47 (`pt-BR`, `en`). schema: type: string X-Request-Id: description: The request id, yours or the one generated here. schema: type: string '429': description: >- - `too_many_requests`: Over the key's budget of 300 requests per minute. Wait the seconds in `Retry-After`. content: application/json: schema: allOf: - $ref: '#/components/schemas/ErrorEnvelope' - type: object properties: code: type: string enum: - too_many_requests headers: Retry-After: description: Seconds to wait before the next request. schema: type: integer X-RateLimit-Limit: description: Requests allowed per minute. schema: type: integer X-RateLimit-Remaining: description: Requests left in the current minute. schema: type: integer Content-Language: description: The language of the body, BCP 47 (`pt-BR`, `en`). schema: type: string X-Request-Id: description: The request id, yours or the one generated here. schema: type: string components: schemas: DispatchPreview: type: object properties: recipients_count: type: integer description: Subscribers eligible right now. credits_cost: type: integer description: 'Credits the send would debit: one per recipient.' current_balance: type: integer sufficient: type: boolean description: Whether `current_balance` covers `credits_cost`. schedule: type: object description: >- The window `scheduled_at` accepts (minutes ahead at least, days ahead at most) and the lead, in minutes, of the low-balance warning. properties: min_lead_minutes: type: integer max_lead_days: type: integer warning_lead_minutes: type: integer required: - min_lead_minutes - max_lead_days - warning_lead_minutes required: - recipients_count - credits_cost - current_balance - sufficient - schedule title: DispatchPreview ErrorEnvelope: type: object description: The shape of every error response of the API. properties: message: type: string description: >- Translated (see `Content-Language`), for display only. Never program against it. code: type: string description: Stable `snake_case` identifier of the error. Program against it. errors: type: object description: >- Only on some errors: the invalid fields of a `validation_failed`, or extra data of a business-rule refusal. required: - message - code title: ErrorEnvelope securitySchemes: apiKey: type: http description: >- An API key created by the chain owner in the panel (**Integrações** → **Nova chave**), sent as `Authorization: Bearer `. The key (`|na_…`) is shown once, at creation; rotate or revoke it on the same screen. It is a server secret: never ship it in browser or mobile code. scheme: bearer ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.