---
title: "LLPA Stack Calculator"
method: POST
path: "/v1/tools/compute_llpa_stack"
tags: ["TODO_TAGS_REVIEW", "TODO_AP2_EXPORT_REVIEW"]
---

# LLPA Stack Calculator

`POST /v1/tools/compute_llpa_stack`

## Request

- Base URL: `https://ainumbers.co`
- URL: `https://ainumbers.co/v1/tools/compute_llpa_stack`
- Auth: none declared

Fannie Mae public LLPA (Loan-Level Price Adjustment) matrix calculator. FICO-by-LTV base grid plus feature surcharges: cash-out refinance, second home, investment property, warrantable condo, subordinate financing. Applies FTHB AMI waiver (SEL-2023-07, up to 1.75 pp reduction for first-time buyers at or below 100% AMI). Table version: FNM-LLPA-2025-11-01 (Fannie Mae public publication). Not check_agency_eligibility_matrix (DU/LPA approval grid) or check_conforming_loan_limit (FHFA size limits).

**Tool URL:** https://ainumbers.co/chaingraph/art-221-llpa-stack.html

## Request body

- object
  - `ami_pct` number: Percentage value
  - `fico_score` number
  - `first_time_buyer` boolean, required
  - `loan_purpose` unknown, required
  - `ltv_pct` number: Percentage value
  - `occupancy_type` unknown, required
  - `property_type` unknown, required
  - `subordinate_financing` boolean, required

## Response `200`

Successful tool execution result

- object
  - `base_llpa` integer
  - `components` object[]
    - `label` string
    - `value` integer
  - `feature_llpa` integer
  - `fico_band` string
  - `fthb_eligible` boolean
  - `fthb_waiver` integer
  - `ltv_band` string
  - `pii_note` string
  - `regulatory_basis` string
  - `table_source` string
  - `table_version` string
  - `total_llpa_pct` integer

---

[API](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite.md) · [All operations](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/llms.txt) · [OpenAPI document](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/revisions/b462e4f5bb28?raw)