Payment Application Processor
Overview
Process construction payment applications from creation through approval. Validate against schedule of values, calculate retainage, generate AIA G702/G703 forms, and track payment status.
Payment Application Flow
┌─────────────────────────────────────────────────────────────────┐
│ PAYMENT APPLICATION FLOW │
├─────────────────────────────────────────────────────────────────┤
│ │
│ Schedule of → Draft → Review → Approve │
│ Values Pay App & Verify & Pay │
│ ────────── ─────── ──────── ──────── │
│ 📋 SOV items 📝 Enter % ✓ Verify ✅ Approve │
│ 💰 Line values 📊 Calculate 📸 Field 💵 Release │
│ 📅 Billing plan 📄 G702/703 📧 Submit 📄 Record │
│ │
└─────────────────────────────────────────────────────────────────┘Technical Implementation
from dataclasses import dataclass, field
from typing import List, Dict, Optional
from datetime import datetime, timedelta
from enum import Enum
class PayAppStatus(Enum):
DRAFT = "draft"
SUBMITTED = "submitted"
UNDER_REVIEW = "under_review"
APPROVED = "approved"
REJECTED = "rejected"
PAID = "paid"
PARTIAL_PAID = "partial_paid"
class LineItemStatus(Enum):
NOT_STARTED = "not_started"
IN_PROGRESS = "in_progress"
COMPLETE = "complete"
@dataclass
class SOVLineItem:
number: str
description: str
scheduled_value: float
previous_completed: float = 0.0
current_completed: float = 0.0
materials_stored: float = 0.0
percent_complete: float = 0.0
balance_to_finish: float = 0.0
retainage: float = 0.0
def calculate(self, retainage_rate: float = 0.10):
"""Calculate line item values."""
self.percent_complete = (
(self.previous_completed + self.current_completed + self.materials_stored)
/ self.scheduled_value * 100
if self.scheduled_value > 0 else 0
)
self.balance_to_finish = (
self.scheduled_value - self.previous_completed -
self.current_completed - self.materials_stored
)
total_completed = self.previous_completed + self.current_completed + self.materials_stored
self.retainage = total_completed * retainage_rate
@dataclass
class PaymentApplication:
application_number: int
project_name: str
contractor: str
period_from: datetime
period_to: datetime
# Contract info
original_contract: float
change_orders: float = 0.0
contract_sum: float = 0.0
# Line items
line_items: List[SOVLineItem] = field(default_factory=list)
# Totals
total_scheduled: float = 0.0
previous_completed: float = 0.0
current_completed: float = 0.0
materials_stored: float = 0.0
total_completed: float = 0.0
percent_complete: float = 0.0
balance_to_finish: float = 0.0
retainage: float = 0.0
net_amount_due: float = 0.0
# Status
status: PayAppStatus = PayAppStatus.DRAFT
submitted_date: Optional[datetime] = None
approved_date: Optional[datetime] = None
approved_amount: float = 0.0
paid_date: Optional[datetime] = None
paid_amount: float = 0.0
# Retainage rates
work_retainage_rate: float = 0.10
stored_retainage_rate: float = 0.10
@dataclass
class G702Data:
"""AIA G702 Application and Certificate for Payment data."""
application_number: int
period_to: datetime
project_name: str
owner: str
contractor: str
architect: str
original_contract_sum: float
net_change_orders: float
contract_sum_to_date: float
total_completed_stored: float
retainage: float
total_earned_less_retainage: float
less_previous_certificates: float
current_payment_due: float
balance_to_finish: float
class PaymentApplicationProcessor:
"""Process construction payment applications."""
def __init__(self, project_name: str, contractor: str,
original_contract: float):
self.project_name = project_name
self.contractor = contractor
self.original_contract = original_contract
self.change_orders_total = 0.0
self.schedule_of_values: List[SOVLineItem] = []
self.pay_apps: Dict[int, PaymentApplication] = {}
self.next_app_number = 1
self.work_retainage_rate = 0.10
self.stored_retainage_rate = 0.10
def set_retainage_rates(self, work_rate: float, stored_rate: float = None):
"""Set retainage rates."""
self.work_retainage_rate = work_rate
self.stored_retainage_rate = stored_rate if stored_rate else work_rate
def add_sov_item(self, number: str, description: str,
scheduled_value: float) -> SOVLineItem:
"""Add line item to schedule of values."""
item = SOVLineItem(
number=number,
description=description,
scheduled_value=scheduled_value
)
self.schedule_of_values.append(item)
return item
def import_sov(self, items: List[Dict]) -> int:
"""Import schedule of values from list."""
count = 0
for item in items:
self.add_sov_item(
item['number'],
item['description'],
item['value']
)
count += 1
return count
def add_change_order(self, amount: float, description: str = ""):
"""Add approved change order to contract."""
self.change_orders_total += amount
# Add as new SOV item
co_number = f"CO-{len([i for i in self.schedule_of_values if 'CO-' in i.number])+1:03d}"
self.add_sov_item(co_number, description or f"Change Order", amount)
def create_pay_app(self, period_from: datetime,
period_to: datetime) -> PaymentApplication:
"""Create new payment application."""
app_number = self.next_app_number
# Copy SOV with previous values
line_items = []
for sov_item in self.schedule_of_values:
# Get previous completed from last pay app
prev_completed = 0.0
if app_number > 1:
prev_app = self.pay_apps.get(app_number - 1)
if prev_app:
prev_item = next(
(i for i in prev_app.line_items if i.number == sov_item.number),
None
)
if prev_item:
prev_completed = (prev_item.previous_completed +
prev_item.current_completed +
prev_item.materials_stored)
line_items.append(SOVLineItem(
number=sov_item.number,
description=sov_item.description,
scheduled_value=sov_item.scheduled_value,
previous_completed=prev_completed
))
pay_app = PaymentApplication(
application_number=app_number,
project_name=self.project_name,
contractor=self.contractor,
period_from=period_from,
period_to=period_to,
original_contract=self.original_contract,
change_orders=self.change_orders_total,
contract_sum=self.original_contract + self.change_orders_total,
line_items=line_items,
work_retainage_rate=self.work_retainage_rate,
stored_retainage_rate=self.stored_retainage_rate
)
self.pay_apps[app_number] = pay_app
self.next_app_number += 1
return pay_app
def update_line_item(self, app_number: int, line_number: str,
current_completed: float = None,
materials_stored: float = None) -> SOVLineItem:
"""Update line item progress."""
if app_number not in self.pay_apps:
raise ValueError(f"Pay app {app_number} not found")
pay_app = self.pay_apps[app_number]
item = next((i for i in pay_app.line_items if i.number == line_number), None)
if not item:
raise ValueError(f"Line item {line_number} not found")
if current_completed is not None:
item.current_completed = current_completed
if materials_stored is not None:
item.materials_stored = materials_stored
item.calculate(pay_app.work_retainage_rate)
# Recalculate pay app totals
self._calculate_totals(pay_app)
return item
def update_by_percentage(self, app_number: int, line_number: str,
percent_complete: float) -> SOVLineItem:
"""Update line item by percentage complete."""
if app_number not in self.pay_apps:
raise ValueError(f"Pay app {app_number} not found")
pay_app = self.pay_apps[app_number]
item = next((i for i in pay_app.line_items if i.number == line_number), None)
if not item:
raise ValueError(f"Line item {line_number} not found")
# Calculate current completed from percentage
total_earned = item.scheduled_value * (percent_complete / 100)
item.current_completed = total_earned - item.previous_completed - item.materials_stored
if item.current_completed < 0:
item.current_completed = 0
item.calculate(pay_app.work_retainage_rate)
self._calculate_totals(pay_app)
return item
def _calculate_totals(self, pay_app: PaymentApplication):
"""Calculate pay app totals."""
pay_app.total_scheduled = sum(i.scheduled_value for i in pay_app.line_items)
pay_app.previous_completed = sum(i.previous_completed for i in pay_app.line_items)
pay_app.current_completed = sum(i.current_completed for i in pay_app.line_items)
pay_app.materials_stored = sum(i.materials_stored for i in pay_app.line_items)
pay_app.total_completed = (
pay_app.previous_completed +
pay_app.current_completed +
pay_app.materials_stored
)
pay_app.percent_complete = (
pay_app.total_completed / pay_app.total_scheduled * 100
if pay_app.total_scheduled > 0 else 0
)
pay_app.balance_to_finish = pay_app.contract_sum - pay_app.total_completed
# Calculate retainage
work_retainage = (pay_app.previous_completed + pay_app.current_completed) * pay_app.work_retainage_rate
stored_retainage = pay_app.materials_stored * pay_app.stored_retainage_rate
pay_app.retainage = work_retainage + stored_retainage
# Previous certificates
previous_certs = 0
if pay_app.application_number > 1:
prev_app = self.pay_apps.get(pay_app.application_number - 1)
if prev_app:
previous_certs = prev_app.total_completed - prev_app.retainage
# Net amount due
pay_app.net_amount_due = (
pay_app.total_completed - pay_app.retainage - previous_certs
)
def submit_pay_app(self, app_number: int) -> PaymentApplication:
"""Submit pay app for review."""
if app_number not in self.pay_apps:
raise ValueError(f"Pay app {app_number} not found")
pay_app = self.pay_apps[app_number]
pay_app.status = PayAppStatus.SUBMITTED
pay_app.submitted_date = datetime.now()
return pay_app
def approve_pay_app(self, app_number: int,
approved_amount: float = None) -> PaymentApplication:
"""Approve pay app."""
if app_number not in self.pay_apps:
raise ValueError(f"Pay app {app_number} not found")
pay_app = self.pay_apps[app_number]
pay_app.status = PayAppStatus.APPROVED
pay_app.approved_date = datetime.now()
pay_app.approved_amount = approved_amount if approved_amount else pay_app.net_amount_due
return pay_app
def record_payment(self, app_number: int, paid_amount: float,
paid_date: datetime = None) -> PaymentApplication:
"""Record payment received."""
if app_number not in self.pay_apps:
raise ValueError(f"Pay app {app_number} not found")
pay_app = self.pay_apps[app_number]
pay_app.paid_date = paid_date or datetime.now()
pay_app.paid_amount = paid_amount
if paid_amount >= pay_app.approved_amount:
pay_app.status = PayAppStatus.PAID
else:
pay_app.status = PayAppStatus.PARTIAL_PAID
return pay_app
def generate_g702(self, app_number: int, owner: str,
architect: str) -> G702Data:
"""Generate AIA G702 data."""
if app_number not in self.pay_apps:
raise ValueError(f"Pay app {app_number} not found")
pay_app = self.pay_apps[app_number]
# Previous certificates
previous_certs = 0
if app_number > 1:
prev_app = self.pay_apps.get(app_number - 1)
if prev_app:
previous_certs = prev_app.total_completed - prev_app.retainage
return G702Data(
application_number=pay_app.application_number,
period_to=pay_app.period_to,
project_name=pay_app.project_name,
owner=owner,
contractor=pay_app.contractor,
architect=architect,
original_contract_sum=pay_app.original_contract,
net_change_orders=pay_app.change_orders,
contract_sum_to_date=pay_app.contract_sum,
total_completed_stored=pay_app.total_completed,
retainage=pay_app.retainage,
total_earned_less_retainage=pay_app.total_completed - pay_app.retainage,
less_previous_certificates=previous_certs,
current_payment_due=pay_app.net_amount_due,
balance_to_finish=pay_app.balance_to_finish
)
def generate_g703(self, app_number: int) -> str:
"""Generate AIA G703 continuation sheet."""
if app_number not in self.pay_apps:
return "Pay app not found"
pay_app = self.pay_apps[app_number]
lines = [
"# AIA G703 - Continuation Sheet",
"",
f"**Application Number:** {pay_app.application_number}",
f"**Period To:** {pay_app.period_to.strftime('%Y-%m-%d')}",
"",
"| Item | Description | Scheduled | Previous | This Period | Stored | Total | % | Balance | Retainage |",
"|------|-------------|-----------|----------|-------------|--------|-------|---|---------|-----------|"
]
for item in pay_app.line_items:
lines.append(
f"| {item.number} | {item.description[:20]} | "
f"${item.scheduled_value:,.0f} | ${item.previous_completed:,.0f} | "
f"${item.current_completed:,.0f} | ${item.materials_stored:,.0f} | "
f"${item.previous_completed + item.current_completed + item.materials_stored:,.0f} | "
f"{item.percent_complete:.0f}% | ${item.balance_to_finish:,.0f} | "
f"${item.retainage:,.0f} |"
)
lines.extend([
"",
f"| **TOTALS** | | ${pay_app.total_scheduled:,.0f} | "
f"${pay_app.previous_completed:,.0f} | ${pay_app.current_completed:,.0f} | "
f"${pay_app.materials_stored:,.0f} | ${pay_app.total_completed:,.0f} | "
f"{pay_app.percent_complete:.0f}% | ${pay_app.balance_to_finish:,.0f} | "
f"${pay_app.retainage:,.0f} |"
])
return "\n".join(lines)
def get_billing_summary(self) -> Dict:
"""Get billing summary across all pay apps."""
total_billed = sum(pa.total_completed for pa in self.pay_apps.values())
total_paid = sum(pa.paid_amount for pa in self.pay_apps.values())
total_retainage = sum(pa.retainage for pa in self.pay_apps.values())
pending = [pa for pa in self.pay_apps.values()
if pa.status in [PayAppStatus.SUBMITTED, PayAppStatus.UNDER_REVIEW, PayAppStatus.APPROVED]]
return {
"contract_sum": self.original_contract + self.change_orders_total,
"total_billed": total_billed,
"total_paid": total_paid,
"total_retainage": total_retainage,
"outstanding": total_billed - total_paid - total_retainage,
"pending_apps": len(pending),
"pending_amount": sum(pa.net_amount_due for pa in pending),
"percent_billed": total_billed / (self.original_contract + self.change_orders_total) * 100
}Quick Start
from datetime import datetime
# Initialize processor
processor = PaymentApplicationProcessor(
project_name="Office Tower",
contractor="ABC Construction",
original_contract=5000000
)
# Import schedule of values
processor.import_sov([
{"number": "01", "description": "General Conditions", "value": 250000},
{"number": "02", "description": "Sitework", "value": 300000},
{"number": "03", "description": "Concrete", "value": 800000},
{"number": "04", "description": "Structural Steel", "value": 1200000},
{"number": "05", "description": "MEP", "value": 1500000},
{"number": "06", "description": "Finishes", "value": 950000},
])
# Create pay application
pay_app = processor.create_pay_app(
period_from=datetime(2024, 1, 1),
period_to=datetime(2024, 1, 31)
)
# Update progress
processor.update_by_percentage(pay_app.application_number, "01", 100) # GC 100%
processor.update_by_percentage(pay_app.application_number, "02", 75) # Site 75%
processor.update_by_percentage(pay_app.application_number, "03", 50) # Concrete 50%
processor.update_line_item(pay_app.application_number, "04",
current_completed=200000, materials_stored=300000)
# Submit and approve
processor.submit_pay_app(pay_app.application_number)
processor.approve_pay_app(pay_app.application_number)
# Generate G703
print(processor.generate_g703(pay_app.application_number))
# Get summary
summary = processor.get_billing_summary()
print(f"Percent Billed: {summary['percent_billed']:.1f}%")Requirements
pip install (no external dependencies)