The doubt always comes the same way: you're applying for credit at BBVA, Santander or Banorte, they ask for proof of income, you don't have a payroll stub because you work for yourself, and the application stalls. Good news: there are several ways to prove income without formal payroll. You just need to assemble the right package.
What the bank really wants when asking for proof
The bank doesn't need a specific paper. What it needs is to prove three things: that you have recurring income, that it's the amount you declared, and that it comes from an identifiable source. Any document combination proving that usually works.
A payroll stub is the most comfortable option because it covers all three in one document. But it's not the only one.
If you're self-employed: the package the bank does accept
The three most recent months of bank statements, where consistent deposits are visible (not necessarily with the same wording, but of the same order of magnitude). It's the strongest document because it comes from a regulated entity and is hard to fake.
SAT constancia de situación fiscal (the complete version, not the summary). Shows your regime, obligations and registered economic activity. Free at sat.gob.mx with RFC and password.
Annual tax return from the last fiscal year. If you file under régimen de incorporación, RESICO or business activity, the annual return is strong proof of last year's income.
If you invoice recurring clients, CFDIs issued in the last three months show how much you billed and to whom. Good complement to the bank statement.
What does NOT work as proof
Self-made receipts in a Word template. Even if labeled as proof, they hold no validity before a bank. Simple rule: the document has to come from an entity other than yourself (bank, SAT, formal employer, client with CFDI).
Mercado Pago, PayPal or similar app screenshots alone. They can complement but not substitute formal bank statements.
Recommendation letters without fiscal formality. A client letter saying «I pay them X per month» is not proof. If that client invoices you, the CFDIs work; the letter doesn't.
How to assemble the package if your income is irregular
Project-based or seasonal income is hardest to prove because it varies month to month. What helps: present 6 months of bank statements instead of the standard 3, and average. The bank sees annual stability even with peaks.
Pair it with annual SAT return showing total yearly income divided by 12. That monthly average is what many banks use to calculate repayment capacity.
If you rent out property
Lease receipts with CFDI are direct proof. Plus SAT constancia where leasing regime appears as declared activity. If you lease to a company that withholds ISR and VAT, the withholdings appear in your SAT portal and reinforce the case.
If you receive dividends or interest
Annual withholding constancia from the paying institution. For dividends from your own company, shareholder meeting minutes plus the year's withholding constancia.
The trick few exploit
If your bureau is good but you lack formal proof, ask the bank for the «alternative proof» modality. Most large banks (BBVA, Banorte, Santander) have internal processes for non-payroll profiles that cross your bureau with last months' banking activity. They don't advertise it, but asking the advisor directly, the application is processed that way. Approved amount is typically 30-50% lower than with formal proof, but at least qualifies.
For small personal credit (under 30,000 pesos), some SOFIPOs like Kubo Financiero ask only for bank statement and SAT constancia, no payroll. Rate is higher than bank but lower than SOFOM.