---
title: "Liquidity topology (Betti numbers)"
method: POST
path: "/v1/hft/liquidity/betti"
---

# Liquidity topology (Betti numbers)

`POST /v1/hft/liquidity/betti`

## Request

- Base URL: `https://financesec.api.caleralabs.com`
- URL: `https://financesec.api.caleralabs.com/v1/hft/liquidity/betti`
- Auth: API key in header `X-License-Key`

Persistent-homology liquidity invariants for a symbol. Also accepts GET ?symbol=.

## Request body

- object
  - `symbol` string

## Response `200`

Betti / spectral-gap snapshot

- HftLiquidityBettiResponse
  - `status` string
  - `symbol` string
  - `betti_0_components` integer
  - `betti_1_cycles` integer
  - `spectral_gap` number
  - `flash_crash_risk_state` string
  - `latency_us` integer

---

[API](https://skmtc.dev/caleralabs/apis/financesec-api-reference.md) · [All operations](https://skmtc.dev/caleralabs/apis/financesec-api-reference/llms.txt) · [OpenAPI document](https://skmtc.dev/caleralabs/apis/financesec-api-reference/revisions/fed76f2ec6e5?raw)