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Personal Finance · head to head

Affirm vs Mercury

Affirm logo

Affirm

Personal Finance

Buy now pay later app offering short interest-free plans and longer plans that charge real APR interest

From
Free
Rated
-
Full reviewWebsite
Mercury logo

Mercury

Accounting

Banking for startups

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Affirm longer instalment plans carry real interest, up to roughly 36 percent APR depending on the retailer, item and applicant, which is a genuine borrowing cost that the buy now pay later framing can obscure for shoppers who do not read the terms shown before accepting.; Mercury treasury access requires a $250,000 balance held with Mercury
  • They diverge on capability: Affirm covers Pay in 4, Mercury covers Business checking.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Affirm and Mercury actually diverge.

Attributes where Affirm and Mercury differ
AttributeAffirmMercury
Pricing modelFree for short Pay in 4 plans; longer plans carry a disclosed APR up to roughly 36 percent, merchant pays a transaction feefreemium
PlatformsiOS, Android, WebWeb, Ios, Android
CategoryPersonal FinanceAccounting
FoundedUnknown2019

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Affirm

  • Pay in 4
  • Monthly instalment loans
  • Soft credit check
  • No late fees
  • Affirm Card
  • Pre-purchase terms disclosure

Only in Mercury

  • Business checking
  • Savings accounts
  • Virtual cards
  • Team management
  • API access
  • QuickBooks
  • Xero
  • Stripe

What people use each for

The jobs each tool is most often brought in to do.

Affirm

  • A shopper financing a large purchase such as furniture or electronics who wants disclosed APR terms compared directly against a credit card before committingnot Mercury
  • Someone using the short Pay in 4 plan for a smaller purchase who intends to pay it off within six weeks with no interestnot Mercury
  • A borrower who has missed a payment before and specifically wants a lender that does not charge late feesnot Mercury
  • A retailer offering point-of-sale financing to reduce cart abandonment on higher-ticket items, in exchange for paying Affirm a transaction feenot Mercury

Mercury

  • Business banking and payments for startupsnot Affirm
  • Managing treasury, invoicing and corporate cards from one accountnot Affirm

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Affirm

  • Longer instalment plans carry real interest, up to roughly 36 percent APR depending on the retailer, item and applicant, which is a genuine borrowing cost that the buy now pay later framing can obscure for shoppers who do not read the terms shown before accepting.
  • Even with no late fees, Affirm reports many loans to credit bureaus, so a missed or late payment on a longer plan can affect a credit score in a way the marketing around interest-free short plans does not prepare shoppers for.
  • Approval and APR both vary by individual loan, so the same shopper can be offered interest-free terms on one purchase and a high APR on another, making the cost unpredictable until checkout.
  • Merchants pay a transaction fee to offer Affirm at checkout, a cost typically built into retail pricing, so shoppers who pay by other means still indirectly subsidise the option even if they never use it.
  • The Affirm Card blurs the line between buy now pay later and a general-purpose credit card, and using it for everyday spending on interest-bearing terms can compound borrowing cost in a way a single point-of-sale purchase would not.

Mercury

  • Treasury access requires a $250,000 balance held with Mercury
  • Non USD international wires carry a 1% conversion fee
  • Choosing OUR wire coding, which covers intermediary bank charges, costs $15 per wire
  • ACH invoicing is $1 per transaction on Mercury Plus and only free on the $299 a month Pro plan
  • Advanced and recurring invoicing require Mercury Plus at $29.90 a month

Pricing, plan by plan

Affirm

Free
  • Pay in 4Free
    • No interest if paid on time over six weeks
    • No late fees for a missed payment
    • Soft credit check at application
  • Monthly instalmentsFree
    • APR disclosed before the loan is accepted, up to roughly 36 percent depending on retailer and applicant
    • Terms from three to 36 months depending on purchase amount
    • Payment history can be reported to credit bureaus

Mercury

Free
  • Mercury (Free)Free
    • ACH payments
    • Domestic wires
    • Real-time payments
  • Mercury Plus$29.9/month
    • Invoice ACH debits
    • Recurring invoices
    • Invoicing API (500/month)
  • Mercury Pro$299/month
    • All Plus features
    • Relationship manager
    • Free ACH invoice debits

Which should you pick?

Choose Affirm if

  • You need pay in 4.
  • You want to start without paying.
  • You work on iOS, Android, Web.
  • You also want monthly instalment loans.
Affirm review

Choose Mercury if

  • You need business checking.
  • You want to start without paying.
  • You work on Web, Ios, Android.
  • You also want savings accounts.
Mercury review

Questions people ask

Is Affirm or Mercury better?
Neither clearly leads. Affirm starts at Free and Mercury at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Affirm or Mercury?
Affirm starts at Free and Mercury at Free.
Does Affirm or Mercury run on more platforms?
Affirm runs on iOS, Android, Web. Mercury runs on Web, Ios, Android.
Can I use Affirm for free?
Both have a free tier, so you can try either at no cost before committing.
What is Affirm best used for?
Affirm is most often used for a shopper financing a large purchase such as furniture or electronics who wants disclosed apr terms compared directly against a credit card before committing, someone using the short pay in 4 plan for a smaller purchase who intends to pay it off within six weeks with no interest, a borrower who has missed a payment before and specifically wants a lender that does not charge late fees, a retailer offering point-of-sale financing to reduce cart abandonment on higher-ticket items, in exchange for paying affirm a transaction fee. Of those, a shopper financing a large purchase such as furniture or electronics who wants disclosed apr terms compared directly against a credit card before committing and someone using the short pay in 4 plan for a smaller purchase who intends to pay it off within six weeks with no interest are not what Mercury is typically brought in for.
What can Affirm do that Mercury cannot?
Affirm covers Pay in 4, Monthly instalment loans, Soft credit check, No late fees. Mercury covers Business checking, Savings accounts, Virtual cards, Team management.

Answered from the vendors’ own pages

Affirm: Does Affirm always charge interest?

No, short Pay in 4 plans over six weeks are typically interest-free if paid on time; longer instalment plans of three to 36 months can carry a disclosed APR up to roughly 36 percent.

Mercury: Is Mercury business banking free?

Mercury's base banking tier is free and includes ACH payments, domestic wire transfers, real-time payments, Bill Pay, and QuickBooks/Xero automations at no monthly cost.

Source
Affirm: Does Affirm charge late fees?

No, Affirm does not charge late fees for a missed payment, unlike some buy now pay later competitors, but missed payments can still be reported to credit bureaus.

Mercury: What does Mercury Plus add beyond the free tier?

Mercury Plus costs $29.90 per month and adds invoice ACH debits, recurring invoice capabilities, invoicing API with 500 calls per month, unlimited 1099 filings, and access to partner benefits.

Source
Affirm: Will using Affirm affect my credit score?

The initial application uses a soft credit check that does not affect your score, but Affirm reports many resulting loans to credit bureaus, so payment history on the loan itself can affect your score.

Mercury: Does Mercury charge monthly account fees?

No, Mercury states there are no minimum account balance requirements, overdraft fees, required monthly fees, or account opening fees. The free tier includes essential business banking, with paid tiers available for additional features.

Source
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