> ## Documentation Index > Fetch the complete documentation index at: https://docs.base44.com/llms.txt > Use this file to discover all available pages before exploring further. # Preview plan change > This API is in beta. Endpoints, fields, and behavior may still change, so avoid depending on it in production. Shows what upgrading your workspace to another plan costs, without changing or charging anything. Pass the price ID of the plan you're considering, from `price_ids` in [List plans](/api-reference/list-plans). Only the workspace owner can preview. The preview mirrors [Change plan](/api-reference/change-plan): `prorated_amount_due` is what that call charges now, and `recurring_amount` is what the new plan costs at each renewal. It previews upgrades only. A downgrade returns 400, because a downgrade charges nothing now and takes effect at the end of the billing period. This previews plans billed through Stripe. For a workspace billed through Wix, use [Preview Wix plan change](/api-reference/preview-wix-plan-change). A Wix-billed workspace can still get a result here, but it doesn't apply to its plan. The base rate limit is 20 requests per minute per user. See [Rate limits](/developers/references/apps-api/get-started/rate-limits) for the multiplier your plan gets. The response includes fields beyond the ones documented here. Don't rely on undocumented response fields, as they can change at any time. ## OpenAPI ````yaml /developers/references/app-management/app-management-openapi.json post /api/billing/preview-upgrade/{price_id} openapi: 3.1.0 info: title: Base44 App Management API version: 1.0.0 servers: - url: https://app.base44.com security: - PersonalAccessTokenAuth: [] paths: /api/billing/preview-upgrade/{price_id}: post: summary: Preview plan change description: >- This API is in beta. Endpoints, fields, and behavior may still change, so avoid depending on it in production. Shows what upgrading your workspace to another plan costs, without changing or charging anything. Pass the price ID of the plan you're considering, from `price_ids` in [List plans](/api-reference/list-plans). Only the workspace owner can preview. The preview mirrors [Change plan](/api-reference/change-plan): `prorated_amount_due` is what that call charges now, and `recurring_amount` is what the new plan costs at each renewal. It previews upgrades only. A downgrade returns 400, because a downgrade charges nothing now and takes effect at the end of the billing period. This previews plans billed through Stripe. For a workspace billed through Wix, use [Preview Wix plan change](/api-reference/preview-wix-plan-change). A Wix-billed workspace can still get a result here, but it doesn't apply to its plan. The base rate limit is 20 requests per minute per user. See [Rate limits](/developers/references/apps-api/get-started/rate-limits) for the multiplier your plan gets. The response includes fields beyond the ones documented here. Don't rely on undocumented response fields, as they can change at any time. operationId: preview_upgrade_api_billing_preview_upgrade__price_id__post parameters: - name: price_id in: path required: true schema: type: string description: >- Price ID of the plan to preview, from `price_ids` in [List plans](/api-reference/list-plans). title: Price Id description: >- Price ID of the plan to preview, from `price_ids` in [List plans](/api-reference/list-plans). example: price_1QxYzAbCdEfGhIjK responses: '200': description: What the upgrade costs now and at renewal. content: application/json: schema: $ref: '#/components/schemas/PlanChangePreview' example: prorated_amount_due: 12.5 currency: usd next_billing_date: 1767225600 recurring_amount: 50 billing_interval: month full_diff: false '400': description: >- `price_id` isn't a plan, the workspace has no active subscription, the target is a downgrade, or the move isn't allowed: a different currency, yearly to monthly billing, or a lower plan while switching to yearly billing. '401': description: >- Missing or invalid credentials. A read-only token gets this response too. '402': description: The workspace has an overdue invoice. Pay it before upgrading. '403': description: You aren't the workspace owner. '409': description: >- The subscription has ended, or the workspace is still on a free migration trial. '429': description: >- Rate limit exceeded. The base rate limit is 20 requests per minute per user. See [Rate limits](/developers/references/apps-api/get-started/rate-limits) for the multiplier your plan gets. security: - PersonalAccessTokenAuth: - full_access components: schemas: PlanChangePreview: properties: prorated_amount_due: type: number title: Prorated Amount Due description: >- Amount [Change plan](/api-reference/change-plan) charges now for this upgrade, in major units of `currency` (dollars, not cents). When `full_diff` is `true`, this is the full price difference rather than a prorated amount. example: 12.5 currency: type: string title: Currency description: Lowercase three-letter currency code of both amounts. example: usd next_billing_date: type: integer title: Next Billing Date description: When the new plan next renews, as a Unix timestamp in seconds. example: 1767225600 recurring_amount: type: number title: Recurring Amount description: >- What the new plan costs at each renewal, in major units of `currency`. example: 50 billing_interval: type: string title: Billing Interval description: 'How often the new plan renews: `month` or `year`.' example: month full_diff: type: boolean title: Full Diff description: >- `true` when `prorated_amount_due` is the full price difference between the plans, not a prorated share of it. example: false type: object required: - prorated_amount_due - currency - next_billing_date - recurring_amount - billing_interval - full_diff title: PlanChangePreview description: What an upgrade costs now and at renewal. securitySchemes: PersonalAccessTokenAuth: type: http scheme: bearer description: >- Personal access token, sent as `Authorization: Bearer `. Each operation lists the permission it needs: `read_only` or `full_access`. A full-access token can call every operation. A read-only token can call only the operations that list `read_only`; anything else returns 403 `read_only_credential_route_not_allowed`. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.