Top Online Banks for SaaS Businesses in 2025: A Detailed Guide

Picking the right online bank for your SaaS company is important, especially when most of your revenue comes from recurring payments. Online banks save you money with lower fees, offer higher interest rates, and automate many financial tasks, making them especially useful for tech startups like yours.

Let’s closely compare four popular online banking options designed to help SaaS companies manage their finances: Mercury, Bluevine, First Internet Bank, and Brex. We’ll discuss interest rates, eligibility requirements, API capabilities, customer service, international support, and account specifics to help you clearly see your options and pick what’s right for your business.

What Are Online Banks, Exactly?

Online banks don’t have physical branches. You do your banking using their website or app. They’re often cheaper, have better interest rates on deposits, and come with integrations or automations to save you time—really helpful for businesses that manage recurring payments, invoices, and a lot of online transactions.

Common features of good online banks include:

• Digital-only accounts, accessible anytime
• FDIC insurance (so your money is safe)
• Easy integration with accounting tools (QuickBooks, Xero)
• Automation through API capabilities for customized banking workflows

1. Mercury

Mercury is geared specifically toward startups and tech companies. If you’ve got larger cash reserves and love automation, Mercury stands out.

Interest Rate Details:

Mercury savings accounts have interest rates based on account balances:

Balance	Interest Rate (APY)
Under $25,000	0.01%
$25,000–$99,999	0.10%
$100,000–$249,999	0.25%
$250,000–$499,999	1.00%
$500,000 or greater	4.50%

Checking accounts do not earn interest. So, while the top rate of 4.50% APY is attractive, it’s only for savings accounts with at least $500,000. Smaller balances earn much less.

APIs & Integration:

Mercury’s API lets you automate:

• Custom payment workflows (ACH and wire payments)
• Sync banking activity directly into your own tools or dashboards (e.g., integrate with CRMs or custom software)
• Automate financial reporting and reconciliation, linked up with platforms like QuickBooks or Xero

Great if you have developers who want custom solutions for your payment processes.

Customer Support:

Mercury provides online support, and if you opt for their premium plan (starting from around $35 per month), you get a dedicated account manager—likely offering faster and more personalized help.

International Features:

Mercury handles international wire transfers, but they’ll charge fees when handling currencies besides USD. For SaaS companies with global clients, it’s worth checking their specific fees, as they may not offer multi-currency accounts or lower-cost international transfers. Given their tech focus, they might be better equipped for global operations, but confirm details directly.

FDIC Insurance:

Mercury partners with multiple FDIC-insured banks to cover your money up to $5 million. They use a network called Insured Cash Sweep, which spreads your deposits across several banks to boost coverage beyond the standard $250,000.

Pros & Cons Recap:

Pros:

• Very high interest (with a large balance)
• Robust, customizable APIs great for SaaS
• Strong reputation among startups (Y Combinator partner)
• High FDIC coverage ($5 million)

Cons:

• Lower balances earn very little interest
• Fees possible on some international transfers and banking activities
• More suitable for companies with higher cash reserves and integration needs

2. Bluevine

Bluevine provides straightforward banking, competitive interest rates, and simple automation good for smaller or mid-sized SaaS companies.

Interest Rate Details:

Bluevine keeps it simple: 1.5% APY on all checking account balances, with no cap and no minimum balance requirement. This makes it appealing for businesses of any size.

APIs & Integration:

Bluevine’s built-in automations mainly cover basic accounts payable—automated bill pay, invoice tracking, and reminders. Unlike Mercury, there’s no extensive developer-facing API for custom workflows. It’s simpler, good if you don’t need deep financial integration.

Customer Support:

Bluevine offers live customer support over phone, online chat, and email during standard business hours. Users report quick responses, but support isn’t available on weekends or outside business hours.

International Features:

Bluevine supports international wire transfers but charges fees outside the U.S., similar to other banks. They don’t offer multi-currency accounts, so expect standard fees for foreign transactions—verify specifics if this is a priority.

FDIC Insurance:

Standard FDIC insurance here—$250,000 per account. No extra partnerships or expanded coverage.

Pros & Cons Recap:

Pros:

• Easy-to-understand rate (1.5%, any amount)
• Useful basic automations, good for smaller teams without a dedicated financial tech person
• Reliable live customer support during business hours

Cons:

• Limited APIs, less suited to heavy custom automation needs
• FDIC coverage capped at standard $250,000
• Less appealing to large businesses holding big cash reserves

3. First Internet Bank

First Internet Bank is traditional online banking—solid and dependable. If you don’t want flashy features, you might like their straightforward approach.

Interest Rate Details:

Its checking account earns:

• 0.50% APY for balances of $10,000 or more
• No interest earned below $10,000

APIs & Integration:

Basic integration with popular accounting software (QuickBooks), but no custom APIs or automation tools. Standard ACH and wire transfer services.

Customer Support:

Available beyond standard hours—including weekends—which can help businesses operating around the clock. However, there’s no dedicated account manager option.

International Features:

International wires supported, like others, but anticipate standard fees for foreign currency transactions. No multi-currency accounts or specialized international features—check fees if you operate globally.

FDIC Insurance:

Standard FDIC protection—up to $250,000 per account owner.

Pros & Cons Recap:

Pros:

• Stable interest for reasonable balance amounts
• Extended customer support hours
• Simple, reliable, traditional online banking

Cons:

• Very limited APY (0.50% only above $10k)
• Not great for SaaS needing automation or integrations
• Standard FDIC coverage only

4. Brex

Brex isn’t exactly a traditional bank—it’s a fintech company offering a cash management account mainly for startups with venture funding or healthy revenue streams.

Interest Rate Details:

• 3.94% APY for its flexible cash management account (no minimum balance)
• This isn’t a checking or savings account; it’s a cash management tool, so some traditional banking features may differ.

APIs & Integration:

Brex connects well to payment processors (Stripe, PayPal, etc.) and accounting tools, but it’s more about spending and expense management than custom transaction automation. No extensive developer APIs for custom payment processing—mostly focused on expense tracking.

Customer Support:

Email and phone-based support, typically with slower response times than Mercury or Bluevine’s live chat. No dedicated account manager.

International Features:

Brex does international wires, like others, but charges standard fees when transferring foreign currencies. They don’t offer multi-currency accounts, so global businesses should verify fees. Their tech focus might suit international needs slightly better, but confirm specifics.

FDIC Insurance:

Up to $6 million through partner banks, dispersing your balance into multiple insured institutions—highly secure for large cash reserves.

Eligibility Requirements:

Brex mostly targets venture-backed startups (typically with Series A funding or higher), companies with established funding rounds, or startups with solid revenue streams. Not open to businesses without significant investment or clear funding status.

Pros & Cons Recap:

Pros:

• Strong APY of 3.94%, no minimum balance
• Great tools for expense management and financial visibility
• High FDIC coverage ($6 million)

Cons:

• Not a real checking/savings bank account (cash management only)—some traditional features may be missing
• Limited eligibility (VC-backed startups or higher cash flow businesses)
• Limited API & automation capabilities focused mostly on expenses

Quick Summary Table:

Bank Name	Max Interest Rate	Account Type	Custom APIs & Automation?	FDIC Insurance	International Transfers	Ideal Customer
Mercury	4.50% (savings, $500K+)	Checking + Savings	Excellent APIs	$5M (multiple banks)	Good (fees apply)	Tech startups with large cash & dev team
Bluevine	1.5% (checking, all)	Checking	Limited automations	$250K standard	Good (fees apply)	Smaller to mid-sized SaaS companies
First Internet	0.50% ($10K+ checking)	Traditional Checking	Accounting integration	$250K standard	Fair (fees apply)	Traditional businesses wanting stability
Brex	3.94% (cash management)	Cash Management Account	Expense integrations only	$6M (multiple banks)	Good (fees apply)	Venture-funded startups, cost management

How to Decide?

• API & Automation Important? Consider Mercury for custom workflows.
• Simple Bank with solid rate and customer support? Bluevine works great.
• Traditional-style banking, less innovation required? First Internet Bank.
• Got a venture-backed startup needing expense & cash management? Brex might be ideal.

Be sure to check individual bank sites (Mercury, Bluevine, First Internet Bank, Brex) for current details before making your final decision. Choose based on your exact needs—cash reserves, integration requirements, international business, and eligibility factors. Hope this helps!