Upload FIEL credentials

Upload your FIEL (Firma Electrónica Avanzada) credentials to enable SAT bulk downloads.

This is the main setup endpoint. It accepts your .cer and .key files, validates them, and — if sync_start_date and phone are provided — automatically registers your business with the SAT in the same request. No separate /register call needed.

What it does:

Validates the certificate format, extracts your RFC, and checks it matches your gigstack team RFC

Verifies the certificate is not expired

Securely encrypts and stores your credentials

If sync_start_date + phone are provided → registers your business with the SAT immediately and enables sync (registered: true in the response)

Request format: multipart/form-data

Field	Type	Required	Description
`cert`	file	Yes	`.cer` file (DER-encoded certificate from SAT)
`key`	file	Yes	`.key` file (DER-encoded encrypted private key from SAT)
`password`	string	Yes	Password for the `.key` file
`sync_start_date`	string	Recommended	Start date for SAT sync (`YYYY-MM-DD`, up to 71 months back)
`phone`	string	Recommended	Contact phone in international format (e.g. `+5215512345678`)

Note: The FIEL is different from the CSD (Certificado de Sello Digital). The CSD is used to stamp CFDI invoices. The FIEL is used to authenticate with the SAT for bulk downloads.

curl --location --request POST 'https://api.gigstack.io/v2/invoices/download/fiel?team' \ --header 'Authorization: <api-key>' \ --form 'cert=@""' \ --form 'key=@""' \ --form 'password=""' \ --form 'sync_start_date="2023-01-01"' \ --form 'phone="+5215512345678"'

{ "success": true, "message": "FIEL credentials stored successfully. Business registered with SAT sync enabled.", "data": { "rfc": "XAXX010101000", "expires_at": 1893456000000, "expires_at_readable": "2029-12-31T00:00:00.000Z", "serial_number": "00001000000504465028", "sync_start_date": "2023-01-01", "phone": "+5215512345678", "registered": true, "registered_at": 0 } }

Upload FIEL credentials

Request

Responses