> ## Documentation Index
> Fetch the complete documentation index at: https://vastai-80aa3a82-examples-openclaw-openai-serverless.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# prepay instance

> Deposit credits into a reserved instance to receive usage discounts.
The discount rate is calculated based on how many months of usage the prepaid amount covers. Maximum discount is typically 40%.

CLI Usage: `vastai prepay instance <id> <amount>`



## OpenAPI

````yaml /api-reference/openapi.yaml put /api/v0/instances/prepay/{id}/
openapi: 3.1.0
info:
  title: Vast.ai API
  description: >-
    Vast.ai REST API for managing GPU cloud instances, machine operations, and
    AI/ML workflows.


    ## AI Agent Quick-Start


    Install the CLI skill for your agent (Claude Code, Cursor, Windsurf, etc.):
      npx skills add vast-ai/vast-cli

    CLI reference:
    https://raw.githubusercontent.com/vast-ai/vast-cli/master/vastai/SKILL.md

    SDK reference:
    https://raw.githubusercontent.com/vast-ai/vast-cli/master/vastai_sdk/SKILL.md


    ## Auth

    All endpoints require `Authorization: Bearer $VAST_API_KEY`.

    Get your key at: https://cloud.vast.ai/manage-keys/


    ## Key Quirks

    - `gpu_ram` in CLI = GB; in REST API = MB (CLI auto-converts)

    - SSH keys must be registered BEFORE creating an instance (VM: no recovery;
    Docker: can add post-create)

    - `onstart` field is limited to 4048 characters -- gzip+base64 for longer
    scripts

    - `POST /api/v0/asks/{id}/` (create instance) returns `new_contract` as the
    instance ID, not `id`

    - Poll trap: if `actual_status` becomes `exited`, `unknown`, or `offline` it
    will never reach `running` -- destroy and retry
  version: 1.0.0
  contact:
    name: Vast.ai Support
    url: https://discord.gg/vast
servers:
  - url: https://console.vast.ai
    description: Production server
security:
  - BearerAuth: []
paths:
  /api/v0/instances/prepay/{id}/:
    put:
      tags:
        - Instances
      summary: prepay instance
      description: >-
        Deposit credits into a reserved instance to receive usage discounts.

        The discount rate is calculated based on how many months of usage the
        prepaid amount covers. Maximum discount is typically 40%.


        CLI Usage: `vastai prepay instance <id> <amount>`
      parameters:
        - in: path
          name: id
          required: true
          schema:
            type: integer
          description: ID of the instance to prepay for
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - amount
              properties:
                amount:
                  type: number
                  format: float
                  description: Amount of credits to prepay
                  example: 500
      responses:
        '200':
          description: Successfully applied prepayment
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: true
                  timescale:
                    type: number
                    format: float
                    description: Number of months the prepayment will cover
                    example: 3.5
                  discount_rate:
                    type: number
                    format: float
                    description: Applied discount rate (0.0-0.4)
                    example: 0.3
        '400':
          description: Invalid instance ID
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: false
                  msg:
                    type: string
                    example: No such instance
        '411':
          description: Insufficient credit balance
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: false
                  msg:
                    type: string
                    example: Insufficient credit
        '429':
          description: Rate limit exceeded
          content:
            application/json:
              schema:
                type: object
                properties:
                  detail:
                    type: string
                    example: API requests too frequent endpoint threshold=2.0
      security:
        - BearerAuth: []
components:
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      description: API key must be provided in the Authorization header

````