Developer API

Property data for your product

Valuations and comparable sales, US-wide, over a simple JSON API. Pay-as-you-go credit packs — one credit per successful call, no monthly minimum. Failed calls are never charged.

1. Get an API key

Create a key in your developer dashboard and buy a credit pack. The full key is shown once — store it securely and send it as a Bearer token. Keys can be revoked at any time.

2. Request a valuation

POST /api/v1/valuation — 1 credit. Rate limit: 30 requests/minute.

cURL

curl -X POST https://taxappealagent.com/api/v1/valuation \
  -H "Authorization: Bearer taa_live_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"address": "123 Main St", "zipCode": "75201"}'

JavaScript

const res = await fetch('https://taxappealagent.com/api/v1/valuation', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer taa_live_YOUR_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ address: '123 Main St', zipCode: '75201' }),
});
const data = await res.json();
console.log(data.valuation.estimate);

Response

{
  "address": "123 Main St",
  "zipCode": "75201",
  "valuation": { "estimate": 425000, "low": 401000, "high": 449000 },
  "comparables": [
    {
      "address": "127 Main St",
      "price": 431000,
      "squareFootage": 1980,
      "distanceMiles": 0.1,
      "listedDate": "2026-03-14T00:00:00.000Z"
    }
  ]
}

Errors

• 401 — missing, malformed, or revoked key
• 402 — out of credits (buy a pack in the dashboard)
• 404 — address not found (no credit charged)
• 429 — rate limit exceeded

Embeddable lead widget

Real-estate sites can embed the free valuation widget to capture seller leads. Create a widget key in the dashboard, whitelist your domains (requests from any other Origin are rejected server-side), then paste:

<div id="taa-widget" data-key="wk_YOUR_WIDGET_KEY"></div>
<script src="https://taxappealagent.com/widget.js" async></script>

Leads (email + address + valuation snapshot) appear in your dashboard. Widget traffic does not consume API credits.