What is a payment aggregator?
It exists so a shop selling twelve mugs a week does not have to negotiate with a bank.
Nine shops, one bank relationship. And the money passes through the middle, which is precisely why the middle needs a licence.
What it replaced
Historically, a business wanting to accept cards negotiated directly with an acquiring bank. That process involved credit checks, paperwork, and months. It worked adequately for large retailers and excluded everyone else.
The aggregator model inverted it. One regulated entity holds the banking relationships, and merchants onboard onto that entity in minutes rather than months. This is the reason a two-person business can accept online payments the same afternoon it decides to.
The crucial detail: the money passes through
An aggregator does not merely route instructions. Customer money genuinely lands in accounts the aggregator controls before being paid out to the merchant.
That single fact is what makes this a regulated activity rather than a software product. Holding other people's money at scale is banking-adjacent, and regulators treat it accordingly.
In India this is explicit: payment aggregators require authorisation from the Reserve Bank of India, must maintain a minimum net worth, and must hold customer funds in a designated escrow account with strict rules about what may be done with them. Payment gateways, by contrast, which only pass instructions and never touch funds, do not require the same licence. That distinction, PA versus PG, is the entire regulatory dividing line and it confuses nearly everyone.
A market organiser who collects payment from every shopper at the gate and settles with each stall at the end of the day is doing something quite different from the sign-maker who wrote the price boards. One of them needs a licence.
Where you meet it
Any small business accepting online payments almost certainly uses an aggregator. If you sell through a marketplace, an aggregator is likely handling the split between the platform's cut and yours.