Fliprofit developer docs

A free, read-only JSON API and a remote MCP server for US reseller fees, payout and profit on 12 marketplaces. They use the same fee engine as the calculators on this site (rates last checked October 24, 2026). No sign-up and no API key.

Reference: OpenAPI 3.1 spec · platform list (JSON) · MCP server card · llms.txt

Quickstart

Fees and profit for one $50 eBay sale:

curl "https://www.fliprofit.com/api/v1/fees/ebay?price=50&shipCharged=8&taxRate=8&itemCost=10&shipCost=7.5"

The same sale on every platform, ranked by profit:

curl "https://www.fliprofit.com/api/v1/compare?price=50&itemCost=10&shipCost=7.5"

Platforms, their options (categories, seller tiers, ad rates) and valid values:

curl "https://www.fliprofit.com/api/v1/fees"

Dated marketplace fee changes, each with the platform's own source (also as an Atom feed):

curl "https://mcp.fliprofit.com/api/v1/changes?upcoming=true"

Inputs (all USD, all optional except price): price, shipCharged, taxRate (percent), itemCost, shipCost, otherCost. Platform keys: ebay, poshmark, mercari, whatnot, depop, etsy, facebook, amazon, grailed, reverb, tcgplayer, tiktok.

Add the MCP server

Remote MCP over Streamable HTTP, no auth: https://mcp.fliprofit.com/mcp. Tools: calculate_fees, compare_platforms, get_fee_changes.

Claude Code:

claude mcp add --transport http fliprofit https://mcp.fliprofit.com/mcp

Cursor (~/.cursor/mcp.json) and most other clients:

{ "mcpServers": { "fliprofit": { "url": "https://mcp.fliprofit.com/mcp" } } }

VS Code (.vscode/mcp.json):

{ "servers": { "fliprofit": { "type": "http", "url": "https://mcp.fliprofit.com/mcp" } } }

Test it with a raw JSON-RPC call:

curl -X POST https://mcp.fliprofit.com/mcp -H "content-type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"calculate_fees","arguments":{"platform":"ebay","price":50}}}'

Authentication and sandbox

None needed. The API is free, keyless and read-only (GET only, CORS open), so there is nothing to sign up for and no separate sandbox: call production directly.

Errors

Every 4xx and 5xx response is RFC 9457 application/problem+json with a stable code:

HTTP/2 400
content-type: application/problem+json; charset=utf-8

{ "type": "https://www.fliprofit.com/developers#error-missing_parameter",
  "title": "Missing required parameter", "status": 400,
  "detail": "price is required, e.g. ?price=50&itemCost=10&shipCost=7.5",
  "code": "missing_parameter", "parameter": "price" }

missing_parameter (400): A required parameter (price on /compare) is missing.
invalid_parameter (400): A number parameter is not a number of 0 or more.
unknown_platform (404): The platform key is not supported. The response lists valid keys.
not_found (404): No endpoint at that path.
method_not_allowed (405): The API is read-only. Use GET (or HEAD/OPTIONS).
rate_limited (429): Over 60 requests per minute from your IP. Wait Retry-After seconds.
internal_error (500): Something failed on our side. Retry, then tell us.

Rate limits

60 requests per minute per IP, on the fee API and the MCP server. Every response has standard headers so clients can pace themselves:

RateLimit-Policy: "per-ip";q=60;w=60
RateLimit: "per-ip";r=59;t=42
RateLimit-Limit: 60
RateLimit-Remaining: 59
RateLimit-Reset: 42

Over the limit you get a 429 rate_limited problem with Retry-After (seconds). Successful responses are cacheable (Cache-Control: max-age=3600), so cache them.

Versioning and deprecation

The major version is in the path: /api/v1. Responses carry API-Version: 1.
Within v1 we only add things: new fields, endpoints, platforms or options. Ignore fields you don't know. Fee numbers change when marketplaces change their rates; the lastChecked date shows when.
Breaking changes ship as a new version (/api/v2); v1 keeps working alongside it.
Before any endpoint or version is retired, its responses carry a Deprecation header (RFC 9745), a Sunset header (RFC 8594) with a retirement date at least 90 days out, and a Link with rel="deprecation" to the notice. Notices are also posted on this page.
Nothing is deprecated today.

Terms of use

The API and MCP server are free and need no key. Please link the matching calculator page when you show or cite a number. Figures are US rates for a standard sale with the options you send; fees change, so check the official source in each result. Not tax or financial advice, and no uptime guarantee.

Support

Wrong number, bug or feature request: email [email protected] or see Contact. Prefer a UI? Try the fee comparison tool.