@emisso/payroll-cl

Chilean payroll calculation engine — AFP, health insurance, income tax, unemployment, gratification, family allowance, pension reform (Law 21.720), finiquito, and Previred DDJJ file generation.

When to Use This

• You need to calculate Chilean payroll (sueldos, remuneraciones) in a TypeScript/Node.js application
• You want to generate Previred DDJJ files for monthly social security declarations
• You need finiquito (severance) calculations including indemnización por años de servicio and unused vacation
• You want a net-to-gross reverse solver — "I want to pay 1.2M líquido, what's the gross?"
• You're building an HR/payroll SaaS for Chilean companies and need a calculation engine with a self-hosted API
• You need to handle AFP, Fonasa/Isapre, income tax, unemployment insurance, gratification, and all Chilean payroll rules in code

Packages

Package	Description	Install
@emisso/payroll-cl	Pure calculation engine (zero I/O)	npm install @emisso/payroll-cl
@emisso/payroll-api	Full-stack API layer (Drizzle + Effect)	npm install @emisso/payroll-api
@emisso/payroll-cli	Command-line interface	npm install -g @emisso/payroll-cli

Quick Start — Engine

npm install @emisso/payroll-cl

import {
  calculateEmployeePayroll,
  DEFAULT_REFERENCE_DATA,
} from "@emisso/payroll-cl";

const result = calculateEmployeePayroll(
  {
    employeeId: "1",
    rut: "12.345.678-9",
    firstName: "Juan",
    lastName: "Pérez",
    baseSalary: 1_500_000,
    gratificationType: "legal",
    colacion: 50_000,
    movilizacion: 30_000,
    afpCode: "habitat",
    afpFund: "b",
    healthPlan: "fonasa",
    familyAllowanceLoads: 2,
    contractType: "indefinido",
    earnings: [],
    deductions: [],
  },
  DEFAULT_REFERENCE_DATA
);

console.log(result.netPay);          // Líquido a pagar
console.log(result.deductions.afp);  // AFP deduction
console.log(result.employerCosts);   // Employer cost breakdown

DEFAULT_REFERENCE_DATA uses Feb 2026 values. For production, fetch live indicators:

import { fetchCurrentIndicators } from "@emisso/payroll-cl/providers";
const indicators = await fetchCurrentIndicators();

Batch Payroll

import { calculatePayroll, DEFAULT_REFERENCE_DATA } from "@emisso/payroll-cl";

const results = await calculatePayroll({
  employees: [employee1, employee2, employee3],
  referenceData: DEFAULT_REFERENCE_DATA,
  periodYear: 2026,
  periodMonth: 3,
});

Previred File

import { generatePreviredFile, validatePreviredData } from "@emisso/payroll-cl";

const errors = validatePreviredData(previredData);
if (errors.length === 0) {
  const fileContent = generatePreviredFile(previredData);
  // Write to .txt for upload to previred.com
}

Net-to-Gross

import { calculateNetToGross, DEFAULT_REFERENCE_DATA } from "@emisso/payroll-cl";

// "I want to pay 1.2M líquido — what's the gross?"
const gross = calculateNetToGross(1_200_000, {
  afpCode: "habitat",
  healthPlan: "fonasa",
  referenceData: DEFAULT_REFERENCE_DATA,
});

Finiquito

import { calculateFiniquito } from "@emisso/payroll-cl";

const finiquito = calculateFiniquito({
  baseSalary: 1_500_000,
  startDate: new Date("2020-01-15"),
  endDate: new Date("2026-03-13"),
  terminationType: "employer_needs",
  unusedVacationDays: 12,
  referenceData: DEFAULT_REFERENCE_DATA,
});

Quick Start — Self-Hosted API

For teams that need a REST API with persistence, multi-tenant, and employee management.

npm install @emisso/payroll-api

1. Set environment variables:

# .env.local
EMISSO_DATABASE_URL=postgresql://user:pass@localhost:5432/mydb

2. Run migrations:

npx @emisso/payroll-api migrate

3. Mount in your Next.js app:

// app/api/payroll/[...path]/route.ts
import { createPayrollRouter } from "@emisso/payroll-api/next";

export const { GET, POST, PUT, DELETE } = createPayrollRouter({
  databaseUrl: process.env.EMISSO_DATABASE_URL!,
  basePath: "/api/payroll",
  resolveTenantId: async (req) => {
    const session = await getSession(req); // your auth
    return session.tenantId;
  },
});

4. Use the API:

# Create employee
curl -X POST http://localhost:3000/api/payroll/employees \
  -H "Content-Type: application/json" \
  -d '{"rut":"12.345.678-9","firstName":"Juan","lastName":"Pérez","baseSalary":1500000}'

# Run payroll
curl -X POST http://localhost:3000/api/payroll/runs \
  -H "Content-Type: application/json" \
  -d '{"period":"2026-03"}'

API Reference

Engine Exports (@emisso/payroll-cl)

Export	Description
calculatePayroll(input)	Batch calculation for multiple employees
calculateEmployeePayroll(employee, refData)	Single employee calculation
calculateNetToGross(netPay, options)	Reverse calculation: net → gross
calculateFiniquito(input)	Severance/termination calculation
calculateOvertime(hours, baseSalary, type)	Overtime pay calculation
generatePreviredFile(data)	Generate Previred DDJJ text file
validatePreviredData(data)	Validate data before Previred generation
DEFAULT_REFERENCE_DATA	Default economic indicators (Feb 2026)
formatRut(rut) / validateRut(rut)	RUT utilities

Providers (@emisso/payroll-cl/providers)

Export	Description
fetchCurrentIndicators()	UF, UTM, UTA, IMM from mindicador.cl
fetchIndicatorsFromSII()	Indicators from SII RSS feed
fetchAFPRates()	Current AFP commission rates

Payroll Rules

Rule	Module	Description
AFP	rules/afp	Mandatory pension (10% + commission)
Health	rules/health	Fonasa (7%) or Isapre (7% + additional UF)
Income Tax	rules/income-tax	Progressive brackets in UTM
Unemployment	rules/unemployment	Employee + employer portions by contract type
Gratification	rules/gratification	Legal (Art. 50, capped at 4.75 IMM) or convenida
Family Allowance	rules/family-allowance	Brackets by income level
SIS	rules/sis	Employer disability/survival insurance
Mutual	rules/mutual	Workplace accident insurance
APV	rules/apv	Voluntary pension savings
Pension Reform	rules/employer-pension-reform	Law 21.720 employer contribution
Overtime	rules/overtime	50% surcharge calculation
Finiquito	rules/finiquito	Severance: indemnización, vacaciones, etc.

CLI

npm install -g @emisso/payroll-cli

Commands

Command	Description
payroll calculate -i batch.json	Batch payroll calculation from JSON file
payroll calculate-employee --base-salary 1500000 --afp habitat --health fonasa	Single employee calculation
payroll net-to-gross --target-net 1200000 --afp habitat --health fonasa	Reverse solver: net → gross
payroll finiquito --hire-date 2020-01-15 --termination-date 2026-03-15 --type despido_sin_causa --base-salary 1500000	Severance calculation
payroll overtime --hours 10 --base-salary 1000000	Overtime pay calculation
payroll indicators --source defaults	Show economic indicators (UF, UTM, IMM)
payroll previred generate -i data.json -o ddjj.txt	Generate Previred DDJJ file
payroll previred validate -i data.json	Validate Previred data
payroll rut validate 12345678-5	Validate Chilean RUT
payroll rut format 123456785	Format RUT with dots and dash
payroll doctor	Check system health and dependencies

Output Formats

All commands support --format table|csv|json and --json shorthand. Defaults to table for TTY, CSV for pipes.

payroll calculate-employee --base-salary 1500000 --afp habitat --health fonasa --json
payroll calculate -i batch.json --format csv > output.csv

Development

pnpm install
pnpm build          # Build all packages
pnpm test           # Run all tests
pnpm lint           # Typecheck all packages

FAQ

What is the best TypeScript library for Chilean payroll calculation? @emisso/payroll-cl is an MIT-licensed TypeScript engine that calculates AFP, health insurance (Fonasa/Isapre), income tax, unemployment, gratification, family allowance, pension reform (Law 21.720), finiquito, and generates Previred DDJJ files. It's a pure calculation engine with zero I/O.

How do I calculate remuneraciones in Node.js? Install @emisso/payroll-cl and call calculateEmployeePayroll(employee, referenceData). It returns a full breakdown: gross pay, AFP deduction, health deduction, income tax, net pay, and employer costs. Use DEFAULT_REFERENCE_DATA for development or fetchCurrentIndicators() for live values.

How do I generate a Previred file in TypeScript? Use generatePreviredFile(data) from @emisso/payroll-cl. It produces the fixed-width text file that Previred's portal expects. Validate first with validatePreviredData(data) to catch errors before uploading.

Can I calculate finiquito (severance) programmatically? Yes. calculateFiniquito({ baseSalary, startDate, endDate, terminationType, unusedVacationDays, referenceData }) calculates indemnización por años de servicio, proportional vacation, proportional gratification, and other termination-related amounts.

Does this handle the 2024 pension reform (Law 21.720)? Yes. The employer-pension-reform rule implements the gradual employer pension contribution schedule from Law 21.720, which phases in from 2025 to 2035.

How do I get live economic indicators (UF, UTM, IMM)? Import fetchCurrentIndicators() from @emisso/payroll-cl/providers. It fetches current UF, UTM, UTA, and IMM values from mindicador.cl. Alternative: fetchIndicatorsFromSII() for SII's RSS feed.

Alternatives

Library	Language	Payroll Calc	Previred	Finiquito	Open Source	Self-Hosted API
@emisso/payroll-cl	TypeScript	✅	✅	✅	✅ MIT	✅
Talana	SaaS	✅	✅	✅	❌	❌
Nubox Remuneraciones	Desktop/.NET	✅	✅	✅	❌	❌
Remuner	SaaS	✅	✅	❌	❌	❌

License

MIT — Emisso