How to use the Seller Fee API in Go

Marketplace and payment fees for Gumroad, Etsy, Stripe and PayPal with net payout breakdowns. This guide calls it from Go with code we've run against the live endpoint.

Online · 1566 msEndpoint tested Nov 15, 2026

1. What you need

Go 1.18 or newer. Save as `main.go` and run `go run main.go`.

No API key or sign-up. Endpoint: https://seller-fee-api.narwhalapis.workers.dev

2. Make the request

package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"time"
)

func main() {
	client := &http.Client{Timeout: 10 * time.Second}
	res, err := client.Get("https://seller-fee-api.narwhalapis.workers.dev")
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	var data any
	json.NewDecoder(res.Body).Decode(&data)
	fmt.Println(data)
}

3. The response

Trimmed from the live response on Nov 15, 2026.

JSON

{
  "name": "Seller Fee API",
  "description": "Fees, net payout and effective rate for Gumroad, Etsy, Stripe and PayPal, plu...",
  "endpoints": [
    "/v1/platforms",
    "/v1/fee",
    "/v1/price"
  ],
  "example": "/v1/compare?amount=20",
  "links": {
    "docs": "https://narwhalthepong.github.io/gumroad-license-check/free-tax-finance-api",
    "rapidapi": "https://rapidapi.com/narwhalapis/api/seller-fee-api-gumroad-etsy-stripe-paypa...",
    "openapi": "/openapi.json",
    "spreadsheet": "https://payhip.com/b/6tHXR"
  },
  "free": "Free to use; please keep request rates reasonable.",
  "version": "1.1.0"
}

4. Before you ship

Set a timeout and handle non-200 responses: free APIs can rate-limit or go down.
Cache responses where you can, instead of calling the API on every page view.
Read the official documentation ↗ for rate limits and terms of use.

FAQ

Does the Seller Fee API need an API key in Go?

No. The Seller Fee API works without an API key, so the Go example runs as-is.

Can I call the Seller Fee API from the browser?

Yes. It sends CORS headers, so front-end JavaScript can call it directly.

What does the Seller Fee API return?

JSON. The example response on this page is trimmed from a real response our health check received on Nov 15, 2026.

Same API in: Python · JavaScript · Node.js · PHP · Java · Ruby · C#
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