# Point-in-time Universe

> Point-in-time Universe is a paid API for AI agents from grok-backtest-api.fly.dev, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-31).

Returns a survivorship-bias-free ranked list of the top-N crypto coins by dollar volume for a given date, suitable for building backtests and live trading universes.

## Facts

- Endpoint: GET https://grok-backtest-api.fly.dev/universe?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/point-in-time-universe-18345963
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zpAJTQ4DCFlysmTlJIAD3

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability point-in-time-universe-18345963
```

Example prompt: Give me the top 50 crypto coins by dollar volume as of 2024-11-15, only including coins that have been trading for at least 35 days and have a 20-day average dollar volume above $1,000,000.

## When to prefer this

Use this endpoint when you need a historically accurate, survivorship-bias-free ranked universe of crypto coins for a specific date — essential for fair backtesting or live strategy universe construction. Prefer this over generic market cap rankings when you need point-in-time correctness (coins that actually existed and were liquid on that date), when you want to filter by minimum listing age and dollar volume thresholds, or when integrating with the sibling backtest and signals endpoints on the same platform. Not suitable for intraday data, order book information, or non-Coinbase-listed assets.

## Known failure modes

- Invalid date format (not YYYY-MM-DD) returns a 400 error
- Date in the future or before Coinbase data availability returns an empty or error response
- top_n out of range (less than 1 or greater than 200) returns a validation error
- min_age_days exceeding 120 returns a validation error
- Payment not provided or insufficient USDC results in a 402 Payment Required response
- Network or server unavailability on fly.dev returns a 5xx error

## How this service works

Top-N Coinbase USD pairs by trailing 20-day dollar volume as of a past date, using only data available that day (survivorship-bias-free universe for backtests).

## Output

A JSON object containing the query date, a ranked array of coins (each with symbol, rank, closing price, age in days, and 20-day average dollar volume), the count of coins returned, and the top_n parameter used. The list is point-in-time accurate and survivorship-bias-free, using Coinbase daily candle data.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "date": {
       "type": "string",
       "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
       "description": "YYYY-MM-DD (default: last completed day)"
      },
      "top_n": {
       "type": "integer",
       "default": 30,
       "maximum": 200,
       "minimum": 1
      },
      "min_age_days": {
       "type": "integer",
       "default": 35,
       "maximum": 120,
       "minimum": 0
      },
      "min_avg_dollar_volume": {
       "type": "number",
       "default": 1000000,
       "minimum": 0
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "date": "2026-07-01",
  "coins": [
   {
    "coin": "BTC-USD",
    "rank": 1,
    "close": 107000,
    "age_days": 162,
    "avg_dollar_volume_20d": 1100000000
   }
  ],
  "count": 3,
  "top_n": 3
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/point-in-time-universe-18345963/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from grok-backtest-api.fly.dev](https://www.zero.xyz/host/grok-backtest-api.fly.dev/llms.txt)