Three different things people mix up
Employer salary advance: your employer lets you take part of wages already earned, often with little or no charge, under its own policy.
Earned-wage access or salary-advance apps: a third party pays a portion of accrued wages, sometimes for a fee or subscription, usually with employer or payroll integration.
High-cost short-term credit: a loan that must be repaid from future income. It is credit, not an early payday, and can be expensive.
Not all advances are credit
An employer paying you for days already worked is not the same as a payday loan. A third-party app may still charge, and repeated use can leave you short on payday. Read the contract.
What to compare
Fee or subscription, whether usage is reported as credit, what happens if you leave the job, and whether you are borrowing against next month rather than unlocking wages already earned.