API REFERENCE
Interactive API Documentation
9 interactive endpoints. Explore parameters, view example responses, and make real API calls directly from this page. All you need is a free API key.
Base URL
https://api.capitoltrace.comAuthentication
Pass your API key via the x-api-key header or Authorization: Bearer <key> header.
Rate Limits
Free
100/day
$0
Starter
1,000/day
$9/mo
Researcher
5,000/day
$29/mo
Widget
10,000/day
$49/mo
Pro
25,000/day
$79/mo
Newsroom
100,000/day
$299/mo
Rate limit headers returned: X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used
M
Members
6 endpoints for member profiles, finances, trading, voting, and ideology
L
Lobbying
Search lobbying filings by client, firm, issue, and amount
E
Executive
Executive orders from the Federal Register
S
System
API usage stats and key management
Response Envelope
Every endpoint wraps its response in a consistent envelope with data, meta, and optionally pagination.
{
"data": "...",
"meta": {
"api_version": "1.0",
"updated_at": "2026-04-03T12:00:00.000Z",
"source": "..."
},
"pagination": {
"total": 541,
"page": 1,
"per_page": 50,
"total_pages": 11
}
}Error Codes
| Status | Error | Description |
|---|---|---|
| 401 | unauthorized | Missing API key. Include x-api-key or Authorization header. |
| 401 | invalid_key | API key not recognized. Check for typos or generate a new key. |
| 403 | insufficient_tier | Your tier cannot access this endpoint. Upgrade at /developers. |
| 429 | rate_limited | Daily request limit exceeded. Resets at midnight UTC. |
| 404 | not_found | Endpoint or resource not found. |
| 405 | method_not_allowed | Only GET and POST /v1/keys are supported. |
| 502 | upstream_error | Upstream data source returned an error. Try again shortly. |
| 500 | internal_error | Unexpected server error. Contact support if persistent. |