Ask most merchants and they'll tell you that payment processing, from integrating services to understanding costs, can be more than a bit opaque. Add in mobile and online channels and things only get worse.

Enter online payment processor Braintree.

Braintree has been making a name for itself lately by catering to developers with tools that make payments simpler. The strategy has been working and the company is now processing more than $5 billion on an annualized basis, working with hot startups like LivingSocial and Uber.

Now Braintree is introducing a product called Braintree Instant that lets online and mobile merchants begin accepting payments almost immediately, without the hassle of obtaining a merchant account or paying the sometimes high rates charged by payment aggregators such as PayPal.

Using Braintree Instant, online and mobile merchants can accept credit and debit payments immediately and gain access to tools that simplify the integration of payments into online and mobile payment flows.

Normally, an SMB could set up an account with a company like PayPal or its competitors to accept electronic payments. But those accounts usually come at a premium and can take days to deposit funds into a merchant's bank account.

The other option, usually open only to larger merchants, is a merchant account through an acquiring bank. Those accounts are cheaper, but merchants have to be approved and there's still a delay in funding to protect the bank against fraud and chargebacks.

Braintree Instant offers another alternative to online merchants, especially those that are hoping to scale over time.

Braintree also takes a page from the Square playbook, making pricing for payments drop-dead simple. With Braintree Instant, there are no monthly minimums and transactions are billed at 2.9 percent, plus $.30 per transaction.

What's more, funds are usually available within two business days, a significant improvement over the three to five days it can take.

"Braintree started with the principle of making payments easily accessible for developers and start-ups, and we've helped thousands of businesses through rapid growth," said Bill Ready, Braintree's CEO, in a statement.

"Now, developers and start-ups can begin accepting payments in a matter of minutes, with the confidence that Braintree has them covered with everything they'll need as they grow their business into the next Uber, Airbnb, LivingSocial or AngryBirds," Ready said.

For more stories like this, visit the mobile In-App Payments research center.