absbox Skill — Quick Start

What is absbox?

absbox is a Python library for modeling and projecting cashflows of structured finance deals (ABS, MBS, CLO, SRT). It wraps the Hastructure computation engine and uses native Python data structures (dicts, lists, tuples) for deal construction.

Quick Setup

pip install absbox           # Python 3.10+ required

from absbox import API, EnginePath

# Connect to engine (pick one)
api = API(EnginePath.PROD, check=False)          # public production
api = API(EnginePath.DEV, check=False)           # public dev
api = API(EnginePath.LOCAL, check=False)         # localhost:8081
api = API("https://absbox.org/api/latest")       # explicit URL

Minimal Deal Example

from absbox import mkDeal

deal = mkDeal({
    "name": "SIMPLE_ABS",
    "dates": {
        "cutoff": "2024-01-01",
        "closing": "2024-02-15",
        "firstPay": "2024-03-20",
        "payFreq": ["DayOfMonth", 20],
        "poolFreq": "MonthEnd",
        "stated": "2034-01-01"
    },
    "pool": {
        "assets": [
            ["Mortgage",
             {"originBalance": 100000, "originRate": ["fix", 0.05],
              "originTerm": 120, "freq": "Monthly", "type": "Level",
              "originDate": "2023-01-01"},
             {"currentBalance": 95000, "currentRate": 0.05,
              "remainTerm": 108, "status": "Current"}]
        ]
    },
    "accounts": {
        "waterfall_acc": {"balance": 0}
    },
    "bonds": {
        "A": {"balance": 80000, "rate": 0.04, "originBalance": 80000,
              "originRate": 0.04, "startDate": "2024-02-15",
              "rateType": {"Fixed": 0.04}, "bondType": {"Sequential": None}},
        "B": {"balance": 15000, "rate": 0.0, "originBalance": 15000,
              "originRate": 0.0, "startDate": "2024-02-15",
              "rateType": {"Fixed": 0.0}, "bondType": {"Equity": None}}
    },
    "waterfall": {
        "amortizing": [
            ["accrueAndPayInt", "waterfall_acc", ["A"]],
            ["payPrin", "waterfall_acc", ["A"]],
            ["payPrinResidual", "waterfall_acc", ["B"]]
        ]
    },
    "collect": [
        ["CollectedInterest", "waterfall_acc"],
        ["CollectedPrincipal", "waterfall_acc"],
        ["CollectedPrepayment", "waterfall_acc"],
        ["CollectedRecoveries", "waterfall_acc"]
    ],
    "status": ("PreClosing", "Amortizing")
})

# Run with assumptions
r = api.run(deal,
    poolAssump=("Pool",
        ("Mortgage", {"CDR": 0.02}, {"CPR": 0.05}, {"Rate": 0.6, "Lag": 12}, None),
        None, None),
    runAssump=[("pricing", {"date": "2024-02-15",
                            "curve": [["2024-01-01", 0.04]]})],
    read=True)

# View results
print(r['bonds']['A'])          # Bond A cashflow
print(r['pool']['flow'])        # Pool cashflow
print(r['result']['logs'])      # Any warnings

File Structure

File	Purpose
SKILL.md	Complete skill document with all sections (primary reference)
REFERENCE.md	Exhaustive lookup tables for formulas, conditions, constants
README.md	This quick start guide

Key Resources

• Documentation: https://absbox-doc.readthedocs.io/en/latest/
• API Reference: https://absbox-doc.readthedocs.io/en/latest/api.html
• Notebook Gallery: https://absbox-doc.readthedocs.io/en/latest/nbsample/index.html
• GitHub: https://github.com/yellowbean/Hastructure