Quick Verdict
Mercury is the better choice for tech founders and startups who need API access, higher FDIC coverage, and a clean interface. Relay wins for cash-flow-heavy businesses (agencies, service businesses, e-commerce) that want multiple sub-accounts to separate money by purpose - Relay's 20 sub-account limit is unmatched in the space.
Overview
Mercury and Relay are both neobank alternatives to traditional business banking, but they serve different primary audiences. Mercury is built for startups and tech companies - it has a developer API, higher FDIC protection, and a UI that prioritizes speed. Relay is built for small businesses that need to manage cash flow intentionally - multiple sub-accounts for taxes, payroll, and operating expenses are its signature feature.
Mercury: For Tech Startups
Mercury's developer API makes it the go-to for startups that want to automate finance workflows - reading balances, initiating payments, and integrating bank data into internal dashboards. Mercury also offers Vault, which sweeps idle cash into money market funds for yield while maintaining FDIC coverage up to $5M. For startups holding significant post-raise cash, this coverage advantage is meaningful.
Relay: For Cash-Flow Management
Relay's sub-account system is designed around the Profit First methodology - separating your business money into buckets (operating, taxes, owner pay, profit). You can create up to 20 checking and 2 savings sub-accounts, all under one login, with separate debit cards for each. This structure forces financial discipline and makes cash flow management visual and concrete.
Mercury Pros
- Up to $5M FDIC via sweep
- Full developer API
- Clean, fast interface
- Mercury Vault for yield
- Better for VC-funded startups
Mercury Cons
- International wires cost $20
- Limited sub-account structure
- Less focus on cash flow methodology
Relay Pros
- Up to 20 sub-accounts (Profit First ready)
- Per-account team permissions
- Dedicated bookkeeper role
- Great for agencies and service businesses
- Free tier is genuinely full-featured
Relay Cons
- Standard FDIC only ($250K)
- Limited API access
- Lower savings yield
- Less tech-startup focused
Frequently Asked Questions
What is the main difference between Mercury and Relay?
Mercury is built for tech startups with developer APIs, higher FDIC coverage, and integrations with startup tooling. Relay is built for cash-flow management with up to 20 sub-accounts, granular team permissions, and a structure that supports the Profit First methodology.
Is Relay good for agencies?
Yes. Relay is particularly popular among agencies, consultants, and service businesses because the sub-account structure maps well to how these businesses need to manage cash - separating operating funds from tax reserves, owner pay, and project-specific accounts.
Does Mercury have an API?
Yes. Mercury offers a full developer API that lets you read account balances, transaction history, and initiate payments programmatically. This makes it popular among technical founders who want to automate financial workflows. Relay's API is more limited.
Which is better for Profit First?
Relay is specifically designed around multi-account structures like Profit First. You can create dedicated accounts for income, operating expenses, taxes, and owner pay, each with its own debit card and team access controls. Mercury can be used for Profit First but requires workarounds.
How do wire fees compare?
Mercury charges $20 per domestic or international wire. Relay charges $10 for domestic wires (free for ACH) and $25 for international wires on the free plan. On Relay Pro ($30/month), wires are included free.