Invoice Submission

Overview

The CompraVenta service handles electronic invoice operations:

Build invoice documents with header and line items
Generate CUF (Código Único de Factura)
Sign XML documents
Compress and hash invoice data
Submit invoices to SIAT
Cancel invoices

Invoice submission requires valid CUIS, CUFD, and a registered point of sale. Complete the setup guides first.

Initialize the Service

import (
    "bytes"
    "compress/gzip"
    "crypto/sha256"
    "encoding/base64"
    "encoding/hex"
    "encoding/xml"
    "time"

    "github.com/ron86i/go-siat"
    "github.com/ron86i/go-siat/internal/core/domain/datatype"
    "github.com/ron86i/go-siat/pkg/config"
    "github.com/ron86i/go-siat/pkg/models"
)

s, err := siat.New("https://pilotosiatservicios.impuestos.gob.bo/v2", nil)
if err != nil {
    log.Fatalf("Error: %v", err)
}

cvService := s.CompraVenta

cfg := config.Config{Token: "YOUR_API_TOKEN"}
ctx := context.Background()

Generate CUF

The CUF is a unique invoice identifier. Generate it before building the invoice:

nit := int64(123456789)
fechaEmision := time.Now()
codigoControl := "XYZ789"  // From CUFD response

cuf, err := models.CompraVenta.GenerarCUF(
    nit,              // Taxpayer NIT
    fechaEmision,     // Invoice date/time
    0,                // Branch code (sucursal)
    1,                // Modality (1=Electronic)
    1,                // Emission type (1=Online)
    1,                // Invoice type (1=With VAT)
    1,                // Document sector (1=Sale/Purchase)
    1,                // Invoice number
    0,                // Point of sale code
    codigoControl,    // CUFD control code
)
if err != nil {
    log.Fatalf("Error generating CUF: %v", err)
}

fmt.Printf("CUF: %s\n", cuf)

The CUF helper uses the Mod 11 algorithm and Base16 encoding as specified by SIAT regulations.

Build Invoice Structure

Build Invoice Header

The header contains seller and buyer information plus totals:

cabeceraReq := models.CompraVenta.NewCabecera().
    // Seller information
    WithNitEmisor(nit).
    WithRazonSocialEmisor("Mi Empresa S.A.").
    WithMunicipio("La Paz").
    WithDireccion("Av. Principal 123").
    
    // Invoice identifiers
    WithNumeroFactura(1).
    WithCuf(cuf).
    WithCufd("CODIGO_CUFD_EJEMPLO").
    WithCodigoSucursal(0).
    WithCodigoPuntoVenta(0).
    WithFechaEmision(fechaEmision.Format("2006-01-02T15:04:05.000")).
    
    // Buyer information
    WithNombreRazonSocial("JUAN PEREZ").
    WithCodigoTipoDocumentoIdentidad(1).  // 1=CI
    WithNumeroDocumento("5544332").
    WithCodigoCliente("CLI-001").
    
    // Payment and amounts
    WithCodigoMetodoPago(1).         // 1=Cash
    WithMontoTotal(100.0).
    WithMontoTotalSujetoIva(100.0).
    WithCodigoMoneda(1).             // 1=BOB
    WithTipoCambio(1.0).
    WithMontoTotalMoneda(100.0).
    
    // Legal requirements
    WithLeyenda("Ley N° 453: El proveedor deberá suministrar el servicio...").
    WithUsuario("admin").
    WithCodigoDocumentoSector(1).    // 1=Sale/Purchase
    Build()

All monetary amounts should be calculated accurately. SIAT validates totals against line items.

Build Line Items (Detalle)

Add one or more line items to the invoice:

detalleReq := models.CompraVenta.NewDetalle().
    WithActividadEconomica("461000").
    WithCodigoProductoSin("12345").      // SIN product code
    WithCodigoProducto("PROD-001").      // Your internal code
    WithDescripcion("Producto de prueba").
    WithCantidad(1.0).
    WithUnidadMedida(57).                // Unit code from catalog
    WithPrecioUnitario(100.0).
    WithSubTotal(100.0).
    Build()

// For multiple items, create additional detalle objects
detalleReq2 := models.CompraVenta.NewDetalle().
    WithActividadEconomica("461000").
    WithCodigoProductoSin("67890").
    WithCodigoProducto("PROD-002").
    WithDescripcion("Servicio de consultoría").
    WithCantidad(2.0).
    WithUnidadMedida(58).
    WithPrecioUnitario(50.0).
    WithSubTotal(100.0).
    Build()

Assemble Complete Invoice

Combine header and line items:

facturaReq := models.CompraVenta.NewFactura().
    WithCabecera(cabeceraReq).
    AddDetalle(detalleReq).
    AddDetalle(detalleReq2).  // Add multiple items
    Build()

Sign and Compress Invoice

Serialize to XML

xmlData, err := xml.Marshal(facturaReq)
if err != nil {
    log.Fatalf("Error serializing XML: %v", err)
}

Sign the XML

Use your digital certificate to sign the invoice:

signedXML, err := models.CompraVenta.SignXML(
    xmlData, 
    "key.pem",   // Path to private key
    "cert.crt",  // Path to certificate
)
if err != nil {
    // In development, you might skip signing
    fmt.Println("Warning: Skipping signature (no certificates)")
    signedXML = xmlData
}

In production, digital signatures are mandatory. Obtain valid certificates from Agencia de Gobierno Electrónico (AGETIC).

Compress with Gzip

var buf bytes.Buffer
zw := gzip.NewWriter(&buf)
if _, err := zw.Write(signedXML); err != nil {
    log.Fatalf("Error compressing XML: %v", err)
}
zw.Close()
compressedBytes := buf.Bytes()

Calculate Hash and Encode

// SHA256 hash of compressed data
hash := sha256.Sum256(compressedBytes)
hashString := hex.EncodeToString(hash[:])

// Base64 encode for transmission
encodedArchivo := base64.StdEncoding.EncodeToString(compressedBytes)

Submit Invoice to SIAT

Build Submission Request

recepcionReq := models.CompraVenta.NewRecepcionFacturaRequest().
    WithCodigoAmbiente(2).               // 2=Pilot
    WithCodigoDocumentoSector(1).
    WithCodigoEmision(1).
    WithCodigoModalidad(1).
    WithCodigoPuntoVenta(0).
    WithCodigoSistema("ABC123DEF").
    WithCodigoSucursal(0).
    WithCufd("CODIGO_CUFD_EJEMPLO").
    WithCuis("C2FC682B").
    WithNit(nit).
    WithTipoFacturaDocumento(1).
    WithArchivo([]byte(encodedArchivo)).    // Base64 encoded
    WithFechaEnvio(datatype.TimeSiat(fechaEmision)).
    WithHashArchivo(hashString).            // SHA256 hash
    Build()

Submit and Validate Response

resp, err := cvService.RecepcionFactura(ctx, cfg, recepcionReq)
if err != nil {
    log.Fatalf("Error submitting invoice: %v", err)
}

if resp != nil && resp.Body.Content.RespuestaServicioFacturacion.Transaccion {
    codigoRecepcion := resp.Body.Content.RespuestaServicioFacturacion.CodigoRecepcion
    fmt.Printf("Success! Reception Code: %s\n", codigoRecepcion)
    
    // Store the reception code for future reference
} else {
    fmt.Printf("Submission failed: %v\n", 
        resp.Body.Content.RespuestaServicioFacturacion.Mensajes)
}

Cancel Invoice

Cancel a previously submitted invoice:

anulacionReq := models.CompraVenta.NewAnulacionFacturaRequest().
    WithCodigoAmbiente(2).
    WithCodigoDocumentoSector(1).
    WithCodigoEmision(1).
    WithCodigoModalidad(1).
    WithCodigoPuntoVenta(0).
    WithCodigoSistema("ABC123DEF").
    WithCodigoSucursal(0).
    WithCufd("CODIGO_CUFD_EJEMPLO").
    WithCuf(cuf).                  // CUF of invoice to cancel
    WithCuis("C2FC682B").
    WithNit(nit).
    WithTipoFacturaDocumento(1).
    WithCodigoMotivo(1).           // Cancellation reason code
    Build()

anulResp, err := cvService.AnulacionFactura(ctx, cfg, anulacionReq)
if err != nil {
    log.Fatalf("Error canceling invoice: %v", err)
}

if anulResp.Body.Content.RespuestaServicioFacturacion.Transaccion {
    fmt.Println("Invoice canceled successfully")
}

Consult the SincronizarParametricaMotivoAnulacion catalog for valid cancellation reason codes.

Complete Example

package main

import (
    "bytes"
    "compress/gzip"
    "context"
    "crypto/sha256"
    "encoding/base64"
    "encoding/hex"
    "encoding/xml"
    "fmt"
    "log"
    "time"

    "github.com/ron86i/go-siat"
    "github.com/ron86i/go-siat/internal/core/domain/datatype"
    "github.com/ron86i/go-siat/pkg/config"
    "github.com/ron86i/go-siat/pkg/models"
)

func main() {
    s, err := siat.New("https://pilotosiatservicios.impuestos.gob.bo/v2", nil)
    if err != nil {
        log.Fatalf("Error: %v", err)
    }

    cvService := s.CompraVenta
    ctx := context.Background()
    cfg := config.Config{Token: "YOUR_API_TOKEN"}

    nit := int64(123456789)
    fechaEmision := time.Now()
    codigoControl := "XYZ789"

    // Generate CUF
    cuf, err := models.CompraVenta.GenerarCUF(
        nit, fechaEmision, 0, 1, 1, 1, 1, 1, 0, codigoControl)
    if err != nil {
        log.Fatalf("Error generating CUF: %v", err)
    }

    // Build invoice
    cabeceraReq := models.CompraVenta.NewCabecera().
        WithNitEmisor(nit).
        WithRazonSocialEmisor("Mi Empresa S.A.").
        WithMunicipio("La Paz").
        WithNumeroFactura(1).
        WithCuf(cuf).
        WithCufd("CODIGO_CUFD_EJEMPLO").
        WithCodigoSucursal(0).
        WithDireccion("Av. Principal 123").
        WithCodigoPuntoVenta(0).
        WithFechaEmision(fechaEmision.Format("2006-01-02T15:04:05.000")).
        WithNombreRazonSocial("JUAN PEREZ").
        WithCodigoTipoDocumentoIdentidad(1).
        WithNumeroDocumento("5544332").
        WithCodigoCliente("CLI-001").
        WithCodigoMetodoPago(1).
        WithMontoTotal(100.0).
        WithMontoTotalSujetoIva(100.0).
        WithCodigoMoneda(1).
        WithTipoCambio(1.0).
        WithMontoTotalMoneda(100.0).
        WithLeyenda("Ley N° 453: El proveedor deberá suministrar el servicio...").
        WithUsuario("admin").
        WithCodigoDocumentoSector(1).
        Build()

    detalleReq := models.CompraVenta.NewDetalle().
        WithActividadEconomica("461000").
        WithCodigoProductoSin("12345").
        WithCodigoProducto("PROD-001").
        WithDescripcion("Producto de prueba").
        WithCantidad(1.0).
        WithUnidadMedida(57).
        WithPrecioUnitario(100.0).
        WithSubTotal(100.0).
        Build()

    facturaReq := models.CompraVenta.NewFactura().
        WithCabecera(cabeceraReq).
        AddDetalle(detalleReq).
        Build()

    // Serialize to XML
    xmlData, err := xml.Marshal(facturaReq)
    if err != nil {
        log.Fatalf("Error serializing XML: %v", err)
    }

    // Sign XML (skip in development if no certificates)
    signedXML, err := models.CompraVenta.SignXML(xmlData, "key.pem", "cert.crt")
    if err != nil {
        fmt.Println("Skipping signature (no certificates available)")
        signedXML = xmlData
    }

    // Compress
    var buf bytes.Buffer
    zw := gzip.NewWriter(&buf)
    if _, err := zw.Write(signedXML); err != nil {
        log.Fatalf("Error compressing: %v", err)
    }
    zw.Close()
    compressedBytes := buf.Bytes()

    // Hash and encode
    hash := sha256.Sum256(compressedBytes)
    hashString := hex.EncodeToString(hash[:])
    encodedArchivo := base64.StdEncoding.EncodeToString(compressedBytes)

    // Submit
    recepcionReq := models.CompraVenta.NewRecepcionFacturaRequest().
        WithCodigoAmbiente(2).
        WithCodigoDocumentoSector(1).
        WithCodigoEmision(1).
        WithCodigoModalidad(1).
        WithCodigoPuntoVenta(0).
        WithCodigoSistema("ABC123DEF").
        WithCodigoSucursal(0).
        WithCufd("CODIGO_CUFD_EJEMPLO").
        WithCuis("C2FC682B").
        WithNit(nit).
        WithTipoFacturaDocumento(1).
        WithArchivo([]byte(encodedArchivo)).
        WithFechaEnvio(datatype.TimeSiat(fechaEmision)).
        WithHashArchivo(hashString).
        Build()

    resp, err := cvService.RecepcionFactura(ctx, cfg, recepcionReq)
    if err != nil {
        log.Fatalf("Error submitting: %v", err)
    }

    if resp != nil && resp.Body.Content.RespuestaServicioFacturacion.Transaccion {
        fmt.Printf("✓ Success! Code: %s\n", 
            resp.Body.Content.RespuestaServicioFacturacion.CodigoRecepcion)
    } else {
        fmt.Printf("✗ Failed: %v\n", 
            resp.Body.Content.RespuestaServicioFacturacion)
    }
}

Builder Pattern Reference

Cabecera (Header) Builder

Method	Description	Required
`WithNitEmisor()`	Seller’s NIT	Yes
`WithRazonSocialEmisor()`	Seller’s business name	Yes
`WithNumeroFactura()`	Sequential invoice number	Yes
`WithCuf()`	Unique invoice code	Yes
`WithCufd()`	Daily billing code	Yes
`WithFechaEmision()`	Emission date (ISO format)	Yes
`WithMontoTotal()`	Total amount	Yes
`WithCodigoMetodoPago()`	Payment method code	Yes
`WithNombreRazonSocial()`	Buyer’s name	Yes
`WithNumeroDocumento()`	Buyer’s document number	Yes

Detalle (Line Item) Builder

Method	Description	Required
`WithActividadEconomica()`	Economic activity code	Yes
`WithCodigoProductoSin()`	SIN product code	Yes
`WithDescripcion()`	Item description	Yes
`WithCantidad()`	Quantity	Yes
`WithUnidadMedida()`	Unit of measure code	Yes
`WithPrecioUnitario()`	Unit price	Yes
`WithSubTotal()`	Line total	Yes

Best Practices

Invoice Numbering

Use sequential numbering per point of sale
Never reuse invoice numbers
Store the last used number in your database
Validate uniqueness before submission

Data Validation

Validate NITs before creating invoices
Verify product codes exist in synced catalogs
Calculate totals accurately (sum of line items)
Format dates in ISO 8601 format

Error Recovery

Store invoice data before submission
Implement retry logic for network failures
Log all submission attempts and responses
Handle duplicate submission errors gracefully

Digital Signatures

Store certificates securely
Monitor certificate expiration dates
Test signature validation regularly
Maintain backup certificates

Next Steps

XML Signing

Learn about digital signature requirements

Error Handling

Handle submission errors and validations

Get Started

Core Concepts

Guides

Invoice Submission

Overview

Initialize the Service

Generate CUF

Build Invoice Structure

Sign and Compress Invoice

Submit Invoice to SIAT

Cancel Invoice

Complete Example

Builder Pattern Reference

Cabecera (Header) Builder

Detalle (Line Item) Builder

Best Practices

Next Steps

XML Signing

Error Handling

Build docs developers (and LLMs) love

Get Started

Core Concepts

Guides

​Overview

​Initialize the Service

​Generate CUF

​Build Invoice Structure

​Sign and Compress Invoice

​Submit Invoice to SIAT

​Cancel Invoice

​Complete Example

​Builder Pattern Reference

​Cabecera (Header) Builder

​Detalle (Line Item) Builder

​Best Practices

​Next Steps

XML Signing

Error Handling

Build docs developers (and LLMs) love

Overview

Initialize the Service

Generate CUF

Build Invoice Structure

Sign and Compress Invoice

Submit Invoice to SIAT

Cancel Invoice

Complete Example

Builder Pattern Reference

Cabecera (Header) Builder

Detalle (Line Item) Builder

Best Practices

Next Steps