Choosing the Best Business Bank for SaaS & Software Publishers: Mercury, Brex, Relay
For SaaS companies and software publishers, your business bank account is more than a safe spot for funds. It's the central hub for your recurring revenue, developer payroll, and cloud hosting spend. Mercury, Brex Cash, and Relay are the top three fintech banks chosen by software startups. They each have unique benefits for things like API access, team payment controls, and how your idle cash can earn money.
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The Quick Answer
Mercury is the go-to for most lean SaaS startups: easy to use, no fees, and a strong API for connecting to your billing (Stripe) or accounting (QuickBooks) software. Relay works best if your software company has many product lines, distinct dev teams, or needs to separate funds for R&D, marketing, and cloud hosting. Brex Cash is smart if you already use Brex cards for team spending on things like developer tools, ad campaigns, or SaaS subscriptions; it brings everything into one dashboard.
Side-by-Side Breakdown
Mercury: Zero monthly fees and no minimum balance. Your funds are FDIC insured up to $5M. Their Treasury product lets funded SaaS companies earn interest on idle cash, which is great for preserving runway between funding rounds. It has a strong API, useful for connecting your finances to subscription billing (Stripe), accounting (QuickBooks), or internal analytics tools. Handles common payments like ACH for payroll, wires for international contractors, and checks for suppliers.
Relay: No monthly fees for basic accounts (Relay Pro costs $30/month for advanced features). Offers up to 20 separate checking accounts and 50 debit cards, perfect for segmenting your SaaS finances. You can create accounts for your R&D budget, AWS or Google Cloud hosting, marketing spend (like Google Ads or LinkedIn Ads), developer payroll, and SaaS subscriptions (CRM, project management). Its strong team permission controls let you set strict spending limits for specific roles, ensuring your marketing manager only spends from the marketing budget, for instance.
Brex Cash: Free when you use the Brex corporate card. FDIC insured up to $6M. It offers a high yield on your operating balance, helping your SaaS company make more from its cash. It’s deeply linked with Brex expense management, giving you one view for spending on developer tools, cloud hosting, SaaS subscriptions, and marketing campaigns. Note: You need the Brex card product to get a Brex Cash account.
When to Choose Mercury
Choose Mercury if your SaaS company is lean, a solo founder project, or a small team needing a clean, free bank account that's ready fast. It's ideal if you need a strong API to integrate with your subscription billing (like Stripe), accounting software (Xero or QuickBooks for investor reports), or custom financial dashboards. It's also great if you want one main account for your operating cash and a separate Treasury option to earn on larger amounts from funding rounds, helping stretch your runway. Mercury is known for its quick approval, often within 24-48 hours, so you can start paying for domains, cloud hosting, and dev tools right away.
When to Choose Relay
Choose Relay when your software company has a growing team with multiple people handling expenses, and you need clear role-based spending controls. It’s perfect if you want to break down your budget into separate virtual accounts for different SaaS functions. For example, one account for your core development team's payroll, another for AWS or Azure hosting costs, a separate one for marketing spend (like ad platforms), and distinct accounts for subscriptions to tools like Figma, Jira, or Salesforce. Relay helps you clearly track spending for each product line or department, giving you tight control over your burn rate.
When to Choose Brex Cash
Choose Brex Cash if your SaaS company already uses the Brex corporate card for expenses like cloud hosting (AWS, Azure), SaaS tool subscriptions (HubSpot, Slack), developer licenses, or marketing campaigns. It gives you one platform for all your spend management, from employee reimbursements to tracking cash flow. You'll get yield on your operating balance, which can help stretch your runway without having to move funds to a separate treasury account. It's great for seeing your corporate card spending and bank balance side-by-side on a single dashboard, simplifying financial oversight for your fast-growing software business.
The Verdict
For most SaaS startups, Mercury is the best place to begin, especially if you're focused on product development and lean operations. It offers strong support for the software startup ecosystem, a clean interface, and no hidden fees. Consider upgrading to Relay if your SaaS company grows to have multiple products, distinct development teams, or complex marketing budgets that need strict account segmentation and team spending controls. Opt for Brex Cash if you're fully committed to the Brex corporate card for all your cloud, subscription, and team expenses, and want a single platform for all your financial tracking.
How to Get Started
Mercury: Apply quickly at mercury.com. You'll need your EIN, business formation papers (like your Certificate of Incorporation), and a personal ID. Approval is often same-day or within 48 hours, letting your SaaS company start paying for critical subscriptions and cloud services almost immediately.
Relay: Apply at relayfi.com. Before you open, plan out your separate accounts for different SaaS budgets—think distinct buckets for R&D, cloud hosting, marketing spend, and developer payroll. Setting this up early avoids reorganizing your financial structure later.
Brex Cash: You open this account when you apply for the Brex corporate card. Remember, you cannot get Brex Cash as a standalone bank account without also getting the Brex card.
RECOMMENDED TOOLS
Mercury
No-fee startup banking with API access
Relay
Multi-account business banking for teams
Brex
Banking + corporate cards in one platform
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FREQUENTLY ASKED QUESTIONS
Are Mercury and Relay real banks?
No. Both are financial technology companies that partner with FDIC-insured banks to hold deposits. Your deposits are FDIC insured, but Mercury and Relay themselves are not chartered banks.
Can I use Mercury or Relay for payroll?
Yes — both support ACH transfers needed for payroll. But most businesses use a dedicated payroll platform (Gusto, Rippling, ADP) and simply connect it to their Mercury or Relay account for the ACH pull.
Which account earns the most interest on cash?
Mercury Treasury earns a competitive yield on balances over $500K. For smaller balances, Brex Cash currently offers the highest yield on operating balances among the three. Rates change frequently, so compare current rates at account opening.