banking-statements

Deterministic parsing, normalization, and validation of U.S. banking statements across institutions and statement formats.

banking-statements is a typed Python library for turning supported bank statements into normalized Python domain objects while preserving the source evidence needed to understand how each result was produced.

The library is designed around isolated statement processors. Each processor owns a known statement format or revision, allowing support for additional banks and statement variants to be added without destabilizing processors already proven against historical statements.

The project emphasizes strict and deterministic behavior. Unsupported statement formats, ambiguous processor matches, malformed recognized data, and unknown statement behavior should fail explicitly rather than being silently ignored or guessed.

Version 0.2.0 introduced real Chase credit-card statement support on top of the generic package foundation established in 0.1.0. Current development also includes Chase checking statement support through an isolated checking processor. Both processor families have been developed against private historical corpora spanning observed statement formats from 2019 through 2026. Public tests remain fully synthetic and contain no private financial data.

The package intentionally focuses on answering:

What did this bank statement say?

It is not a budgeting application, bank API client, accounting system, merchant-categorization engine, personal finance manager, tax engine, database layer, or Beancount-specific importer.

• PyPI: https://pypi.org/project/banking-statements/
• Source: https://github.com/fifoa-labs/banking-statements
• License: MIT

Current Status

Current release:

banking-statements 0.2.0

Supported Python versions:

Python 3.11
Python 3.12
Python 3.13
Python 3.14

Current implemented statement support:

Chase
    credit cards
        modern statement layouts
        historical statement layouts
        co-branded statement layouts
        observed formats spanning 2019–2026

    checking
        Chase Total Checking statements
        multi-page transaction detail
        wrapped transaction descriptions
        observed formats spanning 2019–2026

Current normalized domain includes:

StatementSource
SourceEvidence
StatementPeriod
StatementBalanceSummary
ParsedStatement

AccountType
AccountIdentity

TransactionEvent
TransactionDirection

Current Chase credit-card capabilities include account identity, masked and unmasked account numbers, statement periods, opening and closing balances, purchases, payments, merchant credits, fees, interest charges, balance transfers, My Chase Loan activity, promotional adjustments, reversals, cross-year transaction dates, historical transaction-date references, foreign-currency continuation preservation, and statement reconciliation.

Current Chase checking capabilities include account identity, statement periods, beginning and ending balances, signed transaction-table parsing, multi-page transaction detail, wrapped and continued descriptions, deposits, withdrawals, ACH activity, card payments, transfers, fees, credits, cross-year transaction dates, debit/credit normalization, and statement reconciliation. The private checking corpus currently validates 182 of 182 statements with strict reconciliation and zero difference.

Quality gates include Ruff, strict mypy, pytest, 100% branch coverage, distribution validation, typed-wheel validation, and clean-wheel installation.

Installation

Install from PyPI:

pip install banking-statements

With uv:

uv add banking-statements

Or for development:

git clone https://github.com/fifoa-labs/banking-statements.git
cd banking-statements
uv sync --dev

Basic Usage

The package exposes generic domain primitives plus implemented statement processors. Current Chase processor families cover credit cards and checking.

from datetime import date
from decimal import Decimal
from pathlib import Path

from banking_statements import (
    StatementPeriod,
    StatementSource,
    TransactionDirection,
    TransactionEvent,
)

source = StatementSource(
    path=Path("statement.pdf"),
    sha256="example-sha256",
)

period = StatementPeriod(
    start=date(2026, 7, 1),
    end=date(2026, 7, 31),
)

transaction = TransactionEvent(
    date=date(2026, 7, 15),
    amount=Decimal("42.17"),
    direction=TransactionDirection.DEBIT,
    description="Sample purchase",
)

Chase credit-card statements are handled by the stable processor identifier chase.credit_card.v1.

Chase checking statements are handled by:

chase.checking.v1

Chase Credit Card Support

0.2.0 includes real Chase credit-card statement support through:

chase.credit_card.v1

The processor supports compatible modern, historical, and co-branded Chase credit-card statement grammars observed in the private development corpus from 2019 through 2026.

The implementation intentionally tolerates only known PDF text-extraction artifacts demonstrated by real statements. Examples include variants such as Opening/Closing Date versus the extracted form O\pening/Closing Date, and New BalanceversusN`ew Balance`. Broad fuzzy matching and generic character de-duplication are intentionally avoided.

Historical statements may expose full account numbers while newer statements may expose masked numbers. AccountIdentity preserves the display value stated by the source document and separately exposes the last four digits when available.

Statement balances

Supported statements expose generic balance checkpoints:

StatementBalanceSummary(
    opening_balance=...,
    closing_balance=...,
)

These values are parsed as stated by the bank. They are not rewritten to force reconciliation.

Supported activity

The Chase credit-card processor currently normalizes activity including:

purchases
payments
merchant credits
fees
interest charges
balance transfers
My Chase Loan activity
promotional adjustments
reversals

Normalized amounts are positive magnitudes and TransactionDirection carries the economic direction.

Chase Checking Support

Chase checking statements are handled through:

chase.checking.v1

The processor has been validated against a private chronological corpus of 182 statements spanning observed formats from 2019 through 2026. The complete private corpus currently passes strict parsing and reconciliation:

182 / 182 PASS
reconciliation=PASS
difference=0.00

The parser supports statement identity, reporting periods, beginning and ending balances, transaction-detail tables, multi-page activity sections, wrapped transaction descriptions, and normalized checking transactions.

Checking transaction rows are reconstructed from statement text shaped like:

DATE DESCRIPTION AMOUNT BALANCE

The signed statement amount is interpreted from the checking account's perspective:

positive amount
    → CREDIT

negative amount
    → DEBIT

Normalized TransactionEvent.amount values remain positive magnitudes while TransactionDirection carries the economic direction.

Chase checking statements can include description continuations on later physical lines. The processor reconstructs those logical rows before economic normalization rather than silently discarding continuation content.

The running-balance column remains parser evidence from the source statement; the normalized public transaction model intentionally stays focused on the transaction date, amount, direction, description, and optional source evidence.

Reconciliation

Reconciliation is optional and separate from parsing.

from banking_statements.reconciliation import reconcile_statement

result = reconcile_statement(statement)

Reconciliation is account-type aware.

For credit-card balances:

opening balance
+ parsed debits
- parsed credits
= expected closing balance

For deposit accounts such as checking and savings:

opening balance
+ parsed credits
- parsed debits
= expected closing balance

The result includes the parsed debit and credit totals, expected closing balance, difference, and a reconciled boolean. A mismatch does not modify or reject the parsed statement.

The private archive smoke tooling is stricter by default and treats a reconciliation mismatch as a smoke failure so incomplete or misdirected activity is surfaced during development.

Financial Values

Financial values use Decimal.

from decimal import Decimal

from banking_statements import to_decimal

assert to_decimal("123.45") == Decimal("123.45")
assert to_decimal("$1,234.56") == Decimal("1234.56")
assert to_decimal("(42.17)") == Decimal("-42.17")

Floating-point arithmetic is intentionally avoided for normalized financial values.

Source Evidence

Normalized statement data should remain traceable to the source statement.

from pathlib import Path

from banking_statements import SourceEvidence, StatementSource

source = StatementSource(
    path=Path("statement.pdf"),
    sha256="example-sha256",
)

evidence = SourceEvidence(
    source=source,
    page=2,
    section="Account Activity",
    raw_text="07/15 SAMPLE PURCHASE 42.17",
    processor="example.monthly",
    sequence=14,
)

Evidence can preserve information such as:

source file identity
page
section
raw text
processor
sequence

This provenance is important for auditing parser behavior and for future reconciliation layers.

Architecture

The implemented processing pipeline is:

PDF
    ↓
PdfStatementTextReader
    ↓
page-aware StatementText
    ↓
institution detection
    ↓
processor selection
    ↓
identity and statement-balance parsing
    ↓
logical transaction rows
    ↓
focused economic parsing
    ↓
ParsedStatement
    ↓
optional reconciliation

The architecture separates document mechanics from normalized financial meaning.

The domain layer should not depend on:

PDF layouts
regular expressions
specific banks
Django
databases
Beancount
application frameworks

Processor Model

Processors represent known statement grammars.

Conceptually:

class StatementProcessor(Protocol):
    @property
    def name(self) -> str: ...

    def match(
        self,
        text: StatementText,
    ) -> ProcessorMatch: ...

    def parse(
        self,
        source: StatementSource,
        text: StatementText,
    ) -> ParsedStatement: ...

Processors should be narrow enough that previously proven behavior remains stable as the package grows.

A materially different statement structure should generally receive a new processor rather than turning an existing processor into an increasingly broad universal parser.

Deterministic Processor Selection

ProcessorRegistry requires exactly one compatible processor.

0 matches
    → UnsupportedStatementError

1 match
    → selected

2 or more matches
    → AmbiguousProcessorError

There is intentionally no "first matching processor wins" behavior.

Processor registration order must not silently resolve ambiguous statement formats.

Development Philosophy

The central maintenance rule is:

Proven behavior stays stable.

When a future statement fails, the failure should first be classified.

New institution?
    → add institution detection and processor support

Same institution, materially different statement structure?
    → add a new processor

Same processor, new economic capability?
    → add a focused capability module

Same capability, legitimate new grammar?
    → extend only that capability

Unknown or ambiguous input?
    → fail loudly

The package should grow as a library of proven document grammars rather than as one parser that attempts to understand every possible statement.

Strict Failure Policy

A parser success should mean that the known statement grammar was understood.

The package should not silently discard or guess around:

unknown transaction rows
unknown required sections
ambiguous processor matches
ambiguous amounts
unsupported date grammar
malformed recognized rows
unresolved statement identity
invalid normalized output

Specific failures are preferred over generic parse errors because they make future statement support easier to develop and audit.

Logical Rows

PDF extraction often does not produce one physical line per financial transaction.

Real statements may contain:

wrapped descriptions
continuation lines
multi-line ACH details
fragmented columns
inherited dates
page breaks inside tables

When required, processors should reconstruct logical rows before attempting to normalize economic meaning.

physical extracted lines
    ↓
logical statement rows
    ↓
economic normalization

This keeps layout reconstruction separate from transaction interpretation.

Institution Support

Current implemented support:

Chase
    credit cards
    checking

The Chase credit-card processor has been validated against a broad private historical corpus covering observed statement formats from 2019 through 2026.

The Chase checking processor has been validated against a private historical corpus of 182 statements covering observed formats from 2019 through 2026, with all 182 currently passing strict parsing and reconciliation.

Future processor families may include Chase savings, U.S. Bank, Wells Fargo, Capital One, Bank of America, and other U.S. institutions.

A bank or statement format is listed as supported only after its processor has been implemented and validated against real statement evidence.

Private Statement Corpus

Real financial statements used during development are maintained outside the repository.

The expected local structure is:

private-data/
└── statements/
    ├── institution-a/
    ├── institution-b/
    └── ...

private-data/ is excluded from Git.

Real statements, account numbers, transaction histories, names, addresses, and other private financial data must never be committed to the repository or distributed in package artifacts.

Public tests use synthetic statement data.

Statement Inspection

Development includes tooling for inspecting the exact text extracted from a PDF statement.

make inspect-statement \
    file="private-data/statements/example/statement.pdf"

Inspect a specific page:

make inspect-statement \
    file="private-data/statements/example/statement.pdf" \
    page=2

Optionally limit displayed text:

make inspect-statement \
    file="private-data/statements/example/statement.pdf" \
    head=3000

Parser behavior should be developed against the text actually returned by the package's PDF extraction layer rather than assumptions based only on how a PDF looks visually.

Archive Smoke Testing

Institution processors will be validated against private historical statement archives.

The development workflow is intentionally chronological:

01 PASS
02 PASS
03 PASS
04 FAIL

Development stops at the first failure.

That statement is inspected, the failure is classified, and the smallest correct capability is added.

Then the archive is rerun from the beginning.

Typical usage:

make smoke-archive \
    folder="private-data/statements/example"

Limit the run:

make smoke-archive \
    folder="private-data/statements/example" \
    limit=10

Continue after failures when investigating an archive:

make smoke-archive \
    folder="private-data/statements/example" \
    continue=1

A strict smoke PASS means:

document extraction succeeded
institution detection succeeded
processor selection succeeded
statement identity parsed
statement period parsed
opening and closing balances parsed
logical activity reconstructed
transactions normalized
debit/credit direction assigned
statement reconciliation succeeded

Run a single statement and print normalized transactions:

uv run python -m scripts.archive_smoke \
    private-data/statements/chase/credit-card/example.pdf \
    --show-transactions

Allow reconciliation mismatches for investigation without turning them into smoke failures:

uv run python -m scripts.archive_smoke \
    private-data/statements/chase/credit-card \
    --allow-reconciliation-failures

Development

Install development dependencies:

uv sync --dev

Format:

make format

Check formatting:

make format-check

Lint:

make lint

Type check:

make typecheck

Run tests:

make test

Run tests in parallel:

make test-fast

Run branch coverage:

make coverage

The project maintains:

100% branch coverage

Quality Gates

Run the normal validation suite:

make check

Run the CI-equivalent validation pipeline:

make ci

Before preparing a release:

make release-check

The release check validates:

formatting
linting
mypy
100% branch coverage
distribution build
distribution metadata
typed wheel contents
clean-wheel installation

Build

Build the source distribution and wheel:

make build

Validate distributions:

make check-dist

Inspect wheel contents:

make wheel-contents

Install the built wheel into a clean environment:

make install-wheel

The distributed wheel includes:

banking_statements/py.typed

so type information is available to downstream type checkers.

Dependency Management

The project uses uv.

Synchronize the development environment:

make sync

Refresh the lockfile:

make lock

Upgrade dependencies:

make upgrade

uv.lock is committed so CI and local release validation can use reproducible locked environments.

After changing package metadata or dependencies, refresh the lockfile before committing when required:

uv lock

Python Support

Supported Python versions:

Python 3.11
Python 3.12
Python 3.13
Python 3.14

CI validates the full supported version matrix.

Typing

banking-statements is a typed package.

The project uses strict mypy checking during development:

make typecheck

The wheel includes the PEP 561 marker:

banking_statements/py.typed

Scope

The package is intentionally narrow.

It aims to provide:

bank statement parsing
statement normalization
source evidence
processor selection
strict statement validation
optional reconciliation
typed Python domain objects

It does not aim to provide:

online banking access
bank API integrations
budgeting
merchant categorization
tax accounting
bookkeeping rules
ledger rendering
Beancount-specific output
Django integration
database models
REST APIs
background jobs
web interfaces

Those concerns can consume the normalized statement objects produced by this package without becoming responsibilities of the statement parser itself.

Roadmap

Current milestone:

0.2.0
    Chase credit-card statement support
    historical format compatibility
    account identity
    opening and closing balances
    normalized transactions
    statement reconciliation

Current development milestone:

Chase checking
    chase.checking.v1
    account identity
    statement periods
    beginning and ending balances
    multi-page transaction parsing
    wrapped description reconstruction
    debit/credit normalization
    account-type-aware reconciliation
    182 / 182 private statements PASS

Expected next phases:

Chase savings
additional institutions
additional statement grammars
additional reconciliation capabilities when supported by evidence

The roadmap is evidence-driven.

Modules and abstractions should be added because real statement formats require them, not because they appear theoretically useful.

Contributing

Contributions are welcome.

Please read CONTRIBUTING.md before submitting changes.

The most important contribution rule is:

New evidence should extend the system at the smallest correct boundary without destabilizing previously proven processors.

Never include real private financial statements or personally identifiable financial information in issues, pull requests, tests, or commits.

Security

Please report security issues according to SECURITY.md.

Do not disclose private financial information or credentials in public security reports.

License

banking-statements is released under the MIT License.

See LICENSE for details.