Email aarontian2010@gmail.com — you'll hear back from a person, usually within a day. Full reference is in the API docs.

SoldStack — Sold prices for secondhand fashion, in one API call

SoldStack is a developer-facing API that returns clean sold-price comparables for secondhand clothes, shoes and bags from Poshmark. One call returns the median sold price, p10/p90 range, median days to sell, net payout after fees, a suggested max buy price, and a data-confidence score. It also filters raw marketplace search results to keep only listings that actually match the queried item. Live Poshmark data refreshes every 6 hours, and the API is also exposed as a remote MCP server so AI agents like Claude and Cursor can query it.

Key Features

Clean sold comps in one call

Send a brand + item search and get back only the listings that actually sold — off-topic titles, bundles/lots, kids' sizes, other item types, duplicates and price outliers are removed before any math.

Pre-computed pricing stats

Every response includes median, p10/p90 range with outliers trimmed, median days to sell, median net payout after marketplace fees, and a suggested max buy (a third of the net payout) for sourcing decisions.

Buy-or-pass verdict endpoint

POST item plus tag price to /v1/verdict and get a buy or pass decision, e.g. 'Buy · sells for about $194 · pay under $52'.

Confidence scoring

Each result includes a high/medium/low confidence rating with a plain-English note on how far to trust the number.

MCP server for AI agents

Runs as a remote MCP server at /mcp, so Claude, Cursor and other MCP clients can look up sold prices and verdicts with your API key.

Google Sheets integration

No-code usage via a formula like =SOLDPRICE("coach tabby 26") in any cell, or pointed at a whole inventory column.

Live Poshmark data, 6-hour cache

Data comes from Poshmark's public sold listings, fetched live the first time and served from cache for 6 hours; repeated searches and filter changes within that window are free.

How It Works

Request

Send a brand and item search to GET /v1/sold (or /v1/verdict with a cost for a buy/pass verdict) using your X-API-Key header.

Filtering

SoldStack keeps only the sold listings that match the item, discarding off-topic titles, bundles and lots, kids' sizes, other item types, duplicates and price outliers.

Measured response

You receive stats (median, p10/p90, median_days_to_sell, median_net_payout, suggested_max_buy) plus a cleaning.confidence field in a single schema.

Pros & Cons

Pros

Filters junk out of marketplace search results before computing stats, so comps actually match the item
Computes the analytics (median, days to sell, net payout, max buy) you'd otherwise build yourself
Includes a confidence rating with each result so you know how much to trust the numbers
Works in three ways out of the box: REST API, Google Sheets formula, and MCP server for AI agents
Free tier with 100 lookups/month and no card required; cheap $5 one-month pass for short projects
Cached searches (6 hours) are free, so repeated queries and filter changes don't burn lookups

Who It's For

Best for

Developers building resale tools: thrift scanners, listing/price-suggestion tools, browser extensions
Resellers and thrift/consignment sellers who price inventory in Google Sheets without code
AI agent builders who want a remote MCP tool for sold-price lookups and buy/pass verdicts
Teams that need post-2025 alternatives after eBay shut down its public sold-items API

Not ideal for

Anyone needing eBay or multi-marketplace sold data today
Use cases that require real-time (sub-6-hour) sold-price data

Use Cases

Thrift scanner apps: shopper scans a jacket in the aisle, the app calls /v1/verdict and shows buy-or-pass plus max pay before they reach the register

Listing tools: auto-fill a suggested price from actual sold data when a seller types a title

Browser extensions: show sold comps next to a listing while pricing or evaluating offers

Google Sheets inventory pricing for thrift and consignment sellers, no code required

AI agents (Claude, Cursor) querying sold prices via the MCP server

Pricing

Free tier with 100 lookups/month (no card). Paid plans are lookup-based, not seat-based, with 50% off the first 3 months during launch week using code LAUNCH50 (first 20 customers, ends Oct 12). A $5 one-month pass gives 2,500 lookups for 30 days with no subscription. Repeated searches within 6 hours and failed lookups are free.

Free

100 lookups a month, no card required. One key works across the API, Google Sheets and AI agents.

Paid plans

Pay for lookups (full tier prices not listed on the page)

Launch week: 50% off your first 3 months on any paid plan with code LAUNCH50. Repeating a search within 6 hours is free, as is changing filters. Cancel any time.

One-month pass

2,500 lookups for 30 days across Google Sheets, the API or AI agents. One payment, no subscription, nothing to cancel.

FAQ

Where does the data come from?

From Poshmark's public sold listings — the same results a shopper sees when filtering a search to sold items. SoldStack reads them politely, one request at a time, cached for 6 hours.

How fresh is the data?

A search is fetched live the first time, then served from cache for 6 hours. Each item includes its sold date so you can filter to the window you care about.

Does it cover eBay?

Not yet. eBay's sold search sits behind sign-in and a CAPTCHA, and its official sold-data API is closed to new developers. SoldStack won't bypass either and will prioritize a compliant source based on developer votes.

What counts as a lookup?

SoldStack