> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vatic.trading/llms.txt
> Use this file to discover all available pages before exploring further.

# Trade Estimate

> Calculates the exact taker fee and net outcome using Polymarket's April 2025 fee formula: `fee = C × feeRate × p × (1 − p)`. Precision: 5 decimal places.



## OpenAPI

````yaml POST /api/v1/new_fees/trade-estimate
openapi: 3.1.0
info:
  title: Vatic API
  version: 1.0.0
  description: >-
    Polymarket price targets, Hyperliquid prediction market data, market
    timestamps, fee calculators, and order management for systematic prediction
    market trading.
servers:
  - url: https://api.vatic.trading
    description: Production
security: []
paths:
  /api/v1/new_fees/trade-estimate:
    post:
      tags:
        - Fees (April 2025)
      summary: Trade fee estimate (April 2025)
      description: >-
        Calculates the exact taker fee and net outcome using Polymarket's April
        2025 fee formula: `fee = C × feeRate × p × (1 − p)`. Precision: 5
        decimal places.
      operationId: postNewFeesTradeEstimate
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - side
                - makingAmount
                - takingAmount
              properties:
                eventId:
                  type: string
                eventSlug:
                  type: string
                side:
                  type: string
                  enum:
                    - BUY
                    - SELL
                makingAmount:
                  type: number
                takingAmount:
                  type: number
      responses:
        '200':
          description: Fee estimate result
        '400':
          description: Validation error
        '502':
          description: Gamma API unavailable

````