CFDI supplier registration guide

Introduction

Before a supplier can issue CFDI (Comprobante Fiscal Digital por Internet) documents in Mexico, they must be registered with Invopop’s local PAC (Proveedor Autorizado de Certificación), SW Sapien, who signs and submits invoices to the country’s tax authority, the SAT (Servicio de Administración Tributaria). In this guide you’ll learn how to register a supplier using the SAT Mexico app, and how to unregister them when they should no longer issue invoices from your workspace. Once a supplier is registered, continue with the companion guide: Mexico: Issuing invoices.

Prerequisites

To register a supplier with the SAT, you will need:

Supplier Information:
- Name
- Taxpayer ID (RFC - Registro Federal de Contribuyentes)
- Address
- Fiscal regime code (as defined by SAT)
Two certificates required by the SAT:
1. e.firma (FIEL): Confirms your identity before SAT. Required to obtain the CSD below and to authorize the PAC to issue on your behalf as explained in step 3 of the Register a supplier section below.
2. CSD (Certificado de Sello Digital): Required to sign electronic invoices and prove they were issued by you.

-	Sandbox	Live
Supplier	Register a test supplier using one of SW Sapien’s published test CSDs, or register your own	Real RFC and CSD certificate required

Setup

Configure your Invopop workspace for supplier registration by following these steps in the Invopop Console:

These instructions apply to both the sandbox and live environments, with a few exceptions related to supplier data and registration details when real information is not available.

Set up the Supplier Post-Registration Workflow

Template
Code
Build from scratch

SAT supplier post-registration workflow

This workflow marks Suppliers as Registered. You will select this workflow in the SAT (Mexico) app configuration later.

Copy and paste into a new Empty Party workflow code view.

Example SAT supplier post-registration workflow

{
  "name": "SAT supplier post-registration",
  "description": "Mark a SAT supplier as registered",
  "schema": "org/party",
  "steps": [
    {
      "id": "7e8d8070-3870-11ef-af29-4533d56cea03",
      "name": "Set state",
      "config": {
        "state": "registered"
      },
      "summary": "Set state to `registered`{.state .registered}",
      "provider": "silo.state"
    }
  ],
  "rescue": []
}

Before starting, review the workflows guide to understand the general setup process.In Console, create a new workflow and choose Empty Party workflow as the base. Then name the workflow with a descriptive label such as “SAT Post-registration flow”.This workflow is composed of a single step:

Set state - To Registered.

Though you can customize it to suit your needs (adding a webhook, or an email notification after a supplier has been registered.)

Set up the Supplier Registration Workflow

Template
Code
Build from scratch

SAT register supplier workflow

Issues a registration request for a supplier to complete in order to issue invoices through SAT.

Copy and paste into a new Empty Party workflow code view.

Example SAT register supplier workflow

{
  "name": "SAT register supplier",
  "description": "Register a supplier with SAT",
  "schema": "org/party",
  "steps": [
    {
      "id": "1a9bcde0-a816-11ef-87b2-fd751e6d3b88",
      "name": "Sign envelope",
      "provider": "silo.close"
    },
    {
      "id": "2061c540-a816-11ef-87b2-fd751e6d3b88",
      "name": "Register supplier with SAT",
      "provider": "sat-mx.register"
    },
    {
      "id": "6f9282a0-3870-11ef-af29-4533d56cea03",
      "name": "Set state",
      "config": {
        "state": "processing"
      },
      "summary": "Set state to `processing`{.state .processing}",
      "provider": "silo.state"
    }
  ],
  "rescue": [
    {
      "id": "9a7b3d50-1358-11ef-af96-a18cfb3774fa",
      "name": "Set state",
      "config": {
        "state": "error"
      },
      "provider": "silo.state",
      "summary": "Set state to `error`{.state .error}"
    }
  ]
}

Before starting, review the workflows guide to understand the general setup process.In Console, create a new workflow and choose Empty Party workflow as the base. Then name the workflow with a descriptive label such as “SAT Register Supplier”.The new workflow will need to perform these steps:

Sign envelope
Register supplier with SAT
Set state - with configuration set to Processing.

Add any additional steps you may need, and save the new workflow.

Connect the SAT Mexico App

In the left sidebar, under the Configuration section, click Apps. This will display all available apps.Search for SAT Mexico and click Connect. The app will move to the “Enabled Apps” section.Next, click Configure. This will open a dialog on the right with two fields:

Environment: Sandbox / Live
Post-registration workflow: SAT supplier post-registration

Register a supplier

Registering a business entity requires uploading the CSD to our local provider, SW Sapien, via a form (see Step 2: Complete Supplier Registration). This upload goes to either the sandbox or live environment, depending on your SAT Mexico App configuration. Each CSD is tied to an RFC. When you submit an e-invoice, including the supplier’s RFC, SW Sapien checks for a valid CSD linked to it, as SAT requires a valid certificate to issue invoices.

You can complete this process through the Invopop Console or the API. We’ll walk through it using the Console, but don’t worry, the steps are nearly identical for the API. We’ll add notes along the way to clarify any differences.

Registration is required even in the sandbox now. When following the steps below in that environment, you don’t need a real CSD: you can register either your own company and certificate, or any of the test companies published on the SW Sapien test page, where you can download each test company’s certificate, private key, and password. Either way, make sure the supplier’s name and RFC matches its certificate.

Run the Supplier Registration Workflow

In the left sidebar, go to the Parties section and click Suppliers.Then click +New Supplier and enter the supplier’s data manually using the console, or switch to developer mode (</> icon) to paste the data directly.Here is an example supplier for reference:

Mexico supplier example

{
    "$schema": "https://gobl.org/draft-0/org/party",
    "name": "ESCUELA KEMPER URGATE",
    "tax_id": {
        "country": "MX",
        "code": "EKU9003173C9"
    },
    "addresses": [
        {
            "code": "26015",
            "country": "MX"
        }
    ],
    "ext": {
        "mx-cfdi-fiscal-regime": "601"
    }
}

Click Build, make sure there are no errors, then click Save.Next, click Select Workflow and execute the Supplier Registration Workflow.

Complete Supplier Registration

After it completes, open the Details window and click on Meta. You should see a section called Registration Link with a URL:

You can access the registration link via the API by fetching the silo entry and locating the meta entry where the key is registration-link.

Visit that URL to access the form for registering the supplier.

Note that this form can be shared directly with the supplier if required.

Fill out the form with the following information: Issuer RFC, CSD certificate file (.crt), private key (.key), and the private key password.Follow this guide to generate the CSD certificate and key if you need to.When you click Save, the form details are securely sent to the PAC (Proveedor Autorizado de Certificación), who will handle invoice signing and submission to the SAT.

You can fill the form via API by sending a PUT request to the registration link. The payload should be a JSON object with the following fields:

csd_file (string): The CSD certificate file (.crt).
key_file (string): The private key (.key).
password (string): The private key password.

The response will be a JSON object with the following fields:

rfc (string): The RFC of the supplier.
active_cert (boolean): Whether the certificate is active.

Authorize PAC to Issue Invoices

Since we are using a local PAC, you must authorize the PAC to sign, stamp, and send CFDIs to the SAT on your behalf.To do this, visit the following page and sign the manifesto using your e.firma (FIEL).

At this point, you’re ready to start sending invoices on behalf of the supplier. Head over to the CFDI issuing invoices guide to continue.

Unregister a supplier

Unregistering a supplier revokes their invoice issuing privileges from your workspace. You might need to unregister an entity because the supplier is no longer your client or because of a change in their Tax ID. To do so, use the following workflow template:

Template
Code
Build from scratch

SAT unregister supplier

This workflow will revoke invoice issuing privileges for a SAT supplier.

Copy and paste into a new Empty Party workflow code view.

Example SAT unregister supplier workflow

{
    "name": "SAT unregister supplier",
    "description": "Unregister a supplier from SAT",
    "schema": "org/party",
    "steps": [
        {
            "id": "23affb5e-c15f-4b7b-9517-eaaf4ebd37c1",
            "name": "Unregister supplier from SAT",
            "provider": "sat-mx.unregister"
        },
        {
            "id": "45280ede-ab86-4e76-b55e-7ee744460748",
            "name": "Set state",
            "provider": "silo.state",
            "summary": "Set state to `void`{.state .void}",
            "config": {
                "state": "void"
            }
        }
    ],
    "rescue": [
        {
            "id": "47816a6b-fa58-4b89-ae73-a8eee8e43b0a",
            "name": "Set state",
            "provider": "silo.state",
            "summary": "Set state to `error`{.state .error}",
            "config": {
                "state": "error"
            }
        }
    ]
}

In Console create a new workflow and select Empty Party workflow in the template selector, then add the following steps:

Unregister supplier from SAT - Removes the supplier’s registration so it can no longer issue invoices from this workspace.
Set state - Select void to label the supplier accordingly.

In the Error Handling section, add the Set state action and select Error.

FAQ

Which PAC (Proveedor Autorizado de Certificación) does Invopop use?

Invopop uses SW Sapien, an Authorised Certification Provider (PAC), to sign and stamp CFDI documents for the Mexican tax authority.

What happens if my CSD certificate is revoked?

Without a valid CSD, the issuer cannot stamp any CFDI through any PAC. SAT can administratively revoke a CSD when it suspects fraudulent activity, repeated non-compliance, or tax debts. Operations halt until the supplier resolves the underlying cause and obtains a new CSD. CSDs also expire every four years. Suppliers should monitor CSD validity proactively; Invopop relies on the CSD uploaded during supplier registration and does not manage its lifecycle.

How do I onboard a new supplier in Mexico?

Generate a registration link via the SAT Mexico Register Supplier workflow. The supplier uploads their CSD certificate (.cer + .key + password) and authorizes the PAC. Once validated, the supplier is ready to issue CFDIs.

What certificates does SAT/CFDI require to authenticate a supplier?

A CSD (Certificado de Sello Digital) issued by SAT specifically for invoicing — distinct from the FIEL (e.firma) used for portal login. The CSD comprises a .cer (X.509) and .key (encrypted private key) with a password set at generation. Validity: 4 years.

How are supplier credentials stored in Invopop for Mexico?

The CSD certificate (.cer), private key (.key), and key password are stored encrypted at rest. Invopop uses them only to seal CFDIs before transmission to the PAC; the password and key are never returned in API responses.

More available in our Mexico FAQ section

🇲🇽 Invopop resources for Mexico


Compliance	Invoicing compliance in Mexico Compliance timeline
Apps	SAT Mexico SW Sapien Cron
Guides	Supplier registration Issuing invoices Receiving invoices
FAQ	Mexico FAQ
GOBL	Mexico Tax Regime Mexican SAT CFDI Addon
GitHub	gobl.cfdi

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