> ## Documentation Index > Fetch the complete documentation index at: https://docs.staging.metronome.com/llms.txt > Use this file to discover all available pages before exploring further. # Add a plan to a customer > Associate an existing customer with a plan for a specified date range. See the [price adjustments documentation](https://plans-docs.metronome.com/pricing/managing-plans/#price-adjustments) for details on the price adjustments. This is a Plans (deprecated) endpoint. New clients should implement using Contracts. ## OpenAPI ````yaml /openapi.plans.json post /customers/{customer_id}/plans/add openapi: 3.0.1 info: title: Metronome version: 1.0.0 servers: - url: https://api.metronome.com/v1 description: Production server security: - bearerAuth: [] tags: - name: Customers description: >- [Customers](https://docs.metronome.com/provisioning/create-customers/) in Metronome represent your users for all billing and reporting. Use these endpoints to create, retrieve, update, and archive customers and their billing configuration. - name: Billable metrics description: >- [Billable metrics](https://docs.metronome.com/understanding-metronome/how-metronome-works#billable-metrics) in Metronome represent the various consumption components that Metronome meters and aggregates. - name: Usage description: >- [Usage events](https://docs.metronome.com/connecting-metronome/send-usage-data/) are the basis for billable metrics. Use these endpoints to send usage events to Metronome and retrieve aggregated event data. - name: Plans description: >- [Plans](https://docs.metronome.com/pricing-and-packaging/create-plans/) determine the base pricing for a customer. Use these endpoints to add a plan to a customer, end a customer plan, retrieve plans, and retrieve plan details. Create plans in the [Metronome app](https://app.metronome.com/plans). - name: Contracts description: >- A contract defines a customer’s products, pricing, discounts, commitments, and more. Use these endpoints to create and update contracts data. - name: Credit grants description: >- [Credit grants](https://docs.metronome.com/invoicing/how-billing-works/manage-credits/) adjust a customer balance for prepayments, reimbursements, promotions, and so on. Use these endpoints to create, retrieve, update, and delete credit grants. - name: Invoices description: >- [Invoices](https://docs.metronome.com/invoicing/) reflect how much a customer spent during a period, which is the basis for billing. Metronome automatically generates invoices based upon your pricing, packaging, and usage events. Use these endpoints to retrieve invoices. - name: Alerts description: >- [Alerts](https://docs.metronome.com/connecting-metronome/alerts/) monitor customer spending, balances, and other billing factors. Use these endpoints to create, retrieve, and archive customer alerts. To view sample alert payloads by alert type, navigate [here.](https://docs.metronome.com/manage-product-access/create-manage-alerts/#webhook-notifications) - name: Custom fields description: >- [Custom fields](https://docs.metronome.com/integrations/custom-fields/) enable adding additional data to Metronome entities. Use these endpoints to create, retrieve, update, and delete custom fields. - name: Security description: >- [Security](https://docs.metronome.com/developer-resources/security/) endpoints allow you to retrieve security-related data. - name: Settings description: >- Use these endpoints to configure a billing API key, a webhook secret, or invoice finalization behavior. paths: /customers/{customer_id}/plans/add: post: tags: - Plans summary: Add a plan to a customer description: > Associate an existing customer with a plan for a specified date range. See the [price adjustments documentation](https://plans-docs.metronome.com/pricing/managing-plans/#price-adjustments) for details on the price adjustments. This is a Plans (deprecated) endpoint. New clients should implement using Contracts. operationId: addPlanToCustomer parameters: - $ref: '#/components/parameters/CustomerId' requestBody: description: The customer ID, plan ID, and date range for the plan to be applied content: application/json: schema: $ref: '#/components/schemas/AddPlanToCustomerPayload' example: plan_id: d2c06dae-9549-4d7d-bc04-b78dd3d241b8 starting_on: '2021-02-01T00:00:00Z' ending_before: '2022-02-01T00:00:00Z' responses: '200': description: Success content: application/json: schema: type: object required: - data properties: data: $ref: '#/components/schemas/Id' example: data: id: 8b24d3dc-6db5-432d-9416-8439b3fbf242 components: parameters: CustomerId: name: customer_id in: path required: true schema: type: string format: uuid example: d7abd0cd-4ae9-4db7-8676-e986a4ebd8dc schemas: AddPlanToCustomerPayload: required: - plan_id - starting_on type: object properties: plan_id: type: string format: uuid starting_on: description: >- RFC 3339 timestamp for when the plan becomes active for this customer. Must be at 0:00 UTC (midnight). type: string format: date-time ending_before: description: >- RFC 3339 timestamp for when the plan ends (exclusive) for this customer. Must be at 0:00 UTC (midnight). type: string format: date-time net_payment_terms_days: description: >- Number of days after issuance of invoice after which the invoice is due (e.g. Net 30). type: number price_adjustments: type: array description: >- A list of price adjustments can be applied on top of the pricing in the plans. See the [price adjustments documentation](https://plans-docs.metronome.com/pricing/managing-plans/#price-adjustments) for details. items: type: object required: - charge_id - adjustment_type - start_period properties: charge_id: type: string format: uuid adjustment_type: type: string enum: - percentage - fixed - override - quantity value: type: number description: >- The amount of change to a price. Percentage and fixed adjustments can be positive or negative. Percentage-based adjustments should be decimals, e.g. -0.05 for a 5% discount. quantity: type: number description: the overridden quantity for a fixed charge tier: type: number description: >- Used in pricing tiers. Indicates at what metric value the price applies. start_period: type: number description: >- Used in price ramps. Indicates how many billing periods pass before the charge applies. trial_spec: required: - length_in_days type: object description: >- A custom trial can be set for the customer's plan. See the [trial configuration documentation](https://docs.metronome.com/provisioning/configure-trials/) for details. properties: length_in_days: type: number description: Length of the trial period in days. spending_cap: type: object required: - credit_type_id - amount properties: credit_type_id: type: string description: The credit type ID for the spending cap. amount: type: number description: >- The credit amount in the given denomination based on the credit type, e.g. US cents. overage_rate_adjustments: type: array description: >- An optional list of overage rates that override the rates of the original plan configuration. These new rates will apply to all pricing ramps. items: type: object required: - custom_credit_type_id - fiat_currency_credit_type_id - to_fiat_conversion_factor properties: custom_credit_type_id: type: string format: uuid fiat_currency_credit_type_id: type: string format: uuid to_fiat_conversion_factor: type: number description: >- The overage cost in fiat currency for each credit of the custom credit type. Id: required: - id type: object properties: id: type: string format: uuid securitySchemes: bearerAuth: type: http scheme: bearer ````