Getting Started

Technical reference for the AltIndex REST API. For a quick start, see Getting Started.

Base URL

All API V2 requests use the following base URL:

https://v2.api.altindex.com/api

Authentication

All API requests (except the root endpoint) require authentication via an API key passed in the X-API-Key header.

Request Header

Include your API key in every request:

X-API-Key: your_api_key_here

API Key Format

API keys use a v2_ prefix.

Obtaining an API Key

Create API keys at app.altindex.com/settings (opens in a new tab). Enterprise clients receive custom keys during onboarding.

Access Model

The API is organized into seven data families: entities, score, social, news, employment, ownership, and research. Every plan includes every family. Plans differ in request budget, history window, tickers per call, and MCP access, not in which endpoints you can reach.

If a request asks for something outside your plan, the API refuses it with a 403 Forbidden and a code that names the limit:

{
  "error": {
    "code": "HISTORY_LIMIT_EXCEEDED",
    "message": "The requested range is older than your plan allows.",
    "request_id": "req_abc123..."
  }
}

Rate Limiting

Each plan sets a daily request budget and a per-minute ceiling. Both reset on fixed UTC windows. The daily budget is shared between REST and MCP: one number covers both surfaces.

Plans

Plan	Requests per day	Requests per minute	History window	Tickers per call	MCP
Hobbyist	250	20	30 days	1	No
Developer	1,000	60	2 years	1	Yes
Research	10,000	300	Full history	Up to 50	Yes
Enterprise	Custom	Custom	Full history	Up to 200	Yes

See altindex.com/pricing (opens in a new tab) for plans. For Enterprise access, contact sales (opens in a new tab).

Rate Limit Headers

Every response to an authenticated request carries your remaining budget:

Header	Meaning
`X-RateLimit-Limit`	The limit for the window that refused or served you
`X-RateLimit-Remaining`	Requests left in that window
`X-RateLimit-Reset`	Unix timestamp when the window resets

Rate Limit Exceeded

When you exceed your limit, the API returns a 429 Too Many Requests response with a Retry-After header:

{
  "error": {
    "code": "RATE_LIMIT_EXCEEDED",
    "message": "Daily request limit exceeded.",
    "request_id": "req_abc123..."
  }
}

Best Practices

Cache responses when possible
Use date range filters to reduce data transfer
Read the X-RateLimit-* headers to track your usage

Error Handling

All errors follow a consistent JSON format with a unique request_id for troubleshooting. The full API Reference also lists the specific error codes each endpoint can return.

Error Response Format

{
  "error": {
    "code": "ERROR_CODE",
    "message": "Human-readable error description",
    "request_id": "req_<uuid>"
  }
}

Error Codes

The most common codes:

HTTP Status	Code	Description
401 Unauthorized	`MISSING_API_KEY`	No API key provided in the `X-API-Key` header
403 Forbidden	`INVALID_API_KEY`	API key is invalid or inactive
403 Forbidden	`HISTORY_LIMIT_EXCEEDED`	The requested range is older than your plan allows
403 Forbidden	`TOO_MANY_TICKERS`	More tickers were requested than your plan allows per call
404 Not Found	`TICKER_NOT_FOUND`	That ticker is not in our covered universe
422 Unprocessable Entity	`VALIDATION_ERROR`	Request validation failed
429 Too Many Requests	`RATE_LIMIT_EXCEEDED`	Daily or per-minute request limit exceeded

The API also returns the request_id in the X-Request-ID response header. Quote that value in a support ticket and we can find the request.

OpenAPI Specification

Download the machine-readable spec: /openapi/v2.json

Next Steps

Browse the Reference for endpoint details
Connect AltIndex to your AI assistant via MCP
Explore the Data Dictionary for field definitions and coverage

Getting Started API Reference