Companies with a significant volume of credit/debit card payments rely heavily on payment processors to keep them afloat. Downtime equals lost revenue, so it’s not a function easily entrusted to a startup. That’s why there are fewer players in this category, and the three established ones (Adyen, Square, Stripe) continue to dominate the U.S. SMB market for third-party solutions. Notably, two of three (Adyen, Square) have gone public, further improving trust.
(Note: We exclude the payment arms Amazon or Shopify here since they primarily serve their own marketplaces).
Interestingly, 4 of the 9 startups were launched in the past 4 years. But those 4 are much smaller with combined website traffic of under 200,000 per month. In comparison, the big 3 each have more than 1 million visits each day!
Years since founding:
11 to 20 years >>> 3 startups
6 to 10 years >>> 2 startups
1 to 5 years >>> 4 startups
Note: We divided the payment providers into four categories:
- Charge card and expense management (see list here)
- Bill payments and/or invoicing specialists (list here)
- Payment processors (below)
- Subscription management platforms (list here)
Resources: Looking for digital banks, lenders, payment providers, insurance or digital accounting for small businesses? Check out our latest lists: Small Business (SMB) savings/treasury accounts (7) | SMB online lenders (33) | SMB challenger banks (15) | SMB insurers (15) | SMB credit cards/expense management (16) | Billpay & invoicing (16)| Payment processors (7) | SMB digital accounting/bookkeeping (21)
The FAB Score (Fintech Attention Barometer) is a proxy for the size and growth of fintech companies founded since 1999.
Top U.S. Payment Processing Challengers**
(ranked by FAB score**)
| Rank | Was (Aug’24) | Company | FAB Score | Reviewed | Founded | HQ | Total Funding | Visits (Apr ’26) |
| 1 | 1 | Stripe | 18,460 | 19 May 26 | 2010 | SF | $ 9,390 | 117,000,000 |
| 2 | 2 | Block/Square | 8,212 | 19 May 26 | 2009 | SF | $ 4,800 | 48,400,000 |
| 3 | 3 | Adyen | 4,444 | 19 May 26 | 2006 | Amsterdam | $ 1,366 | 34,400,000 |
| 4 | 5 | Nium | 74 | 19 May 26 | 2015 | Singapore | $ 338 | 130,000 |
| 5 | 4 | Balance | 60 | 19 May 26 | 2020 | Tel Aviv | $ 437 | 45,000 |
| 6 | 6 | Helcim | 56 | 19 May 26 | 2020 | Calgary, Canada | $ 32 | 310,000 |
| 7 | 8 | Link | 33 | 19 May 26 | 2021 | SF | $ 30 | 120,000 |
| 8 | 7 | PaymentCloud | 18 | 19 May 26 | 2016 | LA | $ 45 | 84,000 |
| 9 | 9 | Chargezoom | 11 | 19 May 26 | 2019 | LA | $ 15 | 8,100 |
Source: FintechLabs, 20 May 2026 using data from Crunchbase, SimilarWeb, Pitchbook, LinkedIn, TrustPilot, FeaturedCustomers, Capterra
*Our business model depends on revenue from referrals and sponsors. When you see a referral link in the URL, we may earn a fee when a new account is started (thanks!). This can improve visibility on our website, but does not impact the company’s FAB score.
** The FAB score, Fintech Attention Barometer, is a proxy for the overall size of a private company since they typically do not release traditional metrics (# customers, deposits, AUM, etc). The score is based on VC funding, website traffic, mobile downloads, and the number of employees. It’s a work in progress, so expect changes in the formula.
***Funding invested into the company as either equity or debt.
Challenger Payment Providers in the United States
1. Stripe
FAB Score = 12,240 (up 1,190 from Jan 2024)
– HQ: San Francisco
– Founded: 2010
– Raised $9.4B including $690M in 2024; $6.5B in 2023 (Crunchbase)
– Website visits: 117 million (April 2026) vs. 70 million (Aug 2024; SimilarWeb)
– Employees: 8,500 vs. 8,020 from Mar 2024 through June 2023 (Pitchbook)
– Linkedin: 1.4M followers vs. 900,000 in Aug ’24 (15,300 employees vs. 9,940 in Aug ’24; 8,600 in Jan ’24, 8,000 in June ’23)
– Trustpilot rating: 1.8 (17,100 reviews vs. 14,500 in Aug ’24; 13,000 in Jan ’24)
2. Block/Square
FAB Score = 5,050 (down 80)
– HQ: San Francisco
– Founded: 2009
– Went public Nov 2015 (NYSE:SQ) at $2.9B valuation
– Raised $4.8B including $2.2B Aug 2025, $2B May 2024, $11M in 2021 (Crunchbase)
– Revenue: $24.5B TTM
– Market cap: $41B (19 April 2026)
– Website visits: 48.4M (April 2026) vs. 45.0M (Aug 2024; SimilarWeb)
– Employees: 10,200 vs. 13,000 in Aug ’24; 12,400 Jan ’24 through June ’23 (Pitchbook)
– Linkedin: 700,000 followers vs. 577,000 in Aug. ’24 (6,500 employees vs. 7,110 in Aug ’24; 7,280 in Jan ’24, 7,170 in June ’23)
– Rating: 4.0 (7,320 reviews vs. 5,010 in Aug ’24, 4,320 in Jan ’24 per TrustPilot)
3. Adyen
FAB Score = 4,530 (up 340 since Jan)
– HQ: Amsterdam
– Founded: 2006
– Went public June 2018
– Raised $1.4B all prior to 2021 (Crunchbase)
– Market cap: $34B (19 May 2026)
– Revenues: $2.6B TTM (Yahoo Finance)
– Website visits: 34.4M (April 2026) vs. 35.1 M (Aug 2024; SimilarWeb)
– Employees: 4,470 vs. 4,230 in Aug ’24 (Pitchbook), 3,880 in Jan ’24, 3,330 in June ’23
– Linkedin: 390,000 followers vs. 265,000 in Aug ’24 (5,400 employees vs. 4,600 in Aug ’24; 4,480 in Jan ’24; 4,200 in June ’23)
– Rating: 4.7 (4,780 reviews vs. 3,630 in Aug ’24; 2,830 in Jan ’24 per FeaturedCustomers)
4. Balance
FAB Score = 223 (unchanged)
– HQ: Tel Aviv
– Founded: 2020
– Raised: $437M including $406M in 2022, $15M in 2021 (Crunchbase)
– Website visits: 45,000 (April 2026) vs. 11,000 (Aug 2024; SimilarWeb)
– Employees: 134 vs. 104 in Aug ’24, (Pitchbook), 100 in Jan ’24, 96 in June ’23
– Articles: 46 (Crunchbase)
– Linkedin: 16,000 followers vs 8,000 in Aug ’24 (147 employees vs. 108 in Aug ’24; 94 in Jan. ’24, 98 in June ’23)
5. Nium
FAB Score = 76 (up 29)
– HQ: Singapore
– Founded: 2015
– Raised $338M including $50M in Jun 2024, $200M in 2021, $13M in 2022 (Crunchbase)
– Website visits: 130,000 (April 2026) vs. 100,000 (Aug 2024; SimilarWeb)
– Employees: 997 vs. 985 in Aug ’24; (Pitchbook), 1,000 in Jan ’24, 945 in June ’23
– Articles: 214 (Crunchbase)
– Linkedin: 305,000 followers vs. 205,000 in Aug ’24 (1,060 employees vs. 1,010 in Aug ’24; 1.005 in Jan ’24, 1,030 in June ’23)
– Rating: INA
6. Helcim
FAB Score: 50 (up 18)
HQ: Calgary, Canada
Founded: 2020
Raised: $32M including $20M in Feb 2024, $12M in 2022 (Crunchbase)
Website visits: 310,000 (April 2026) vs. 260,000 (Aug 2024; SimilarWeb)
Employees: 145 vs. 155 in Aug ’24 (Pitchbook); 140 in Jan ’24, 149 in June ’23
Article citations: 16 (Crunchbase)
Linkedin: 17,000 followers vs. 11,000 in Aug ’24 (156 employees vs. 151 in Aug ’24; 137 in Jan ’24, 138 in June ’23)
Trustpilot: 4.1 (953 reviews vs. 489 in Aug ’24; 352 in Jan)
7. PaymentCloud (acquired by Electronic Merchant Systemes)
FAB Score = 42 (up 3)
– HQ: LA (Sherman Oaks)
– Founded: 2016
– Raised $45M including $35M in 2022, $10M in 2021 (Crunchbase)
– Website visits: 84,000 (April 2026) vs. 170,000 (Aug 2024; SimilarWeb)
– Employees: 93 (Pitchbook) unchanged since Aug ’24; vs 86 Jan ’24 through June ’23
– Articles: 24 (Crunchbase)
– Linkedin: 4,500 followers vs. 3,000 in Aug ’24 (67 employees vs. 86 in Aug ’24; 93 in Jan ’24; 87 in June ’23)
– Rating: 4.7 (18 reviews per Capterra)
8. Link
FAB score = 20 (down 2)
HQ: SF
Founded: 2021
Funding: $30M, including $20M in 2023, $10M in 2021 (Crunchbase)
Article citations: 20 (Crunchbase)
Website visits: 120,000 (April 2026) vs. 18,000 (Aug 2024, SimilarWeb)
Employees: 36 vs, 48 in Aug ’24 through Jan ’24 (Pitchbook); 40 in June ’23
LinkedIn: 3,100 followers vs. 2,000 in Aug ’24 (50 employees in Aug ’24 vs. 47 in Jan ’24, 57 in June ’23)
9. Chargezoom
FAB Score = 11 (unchanged)
HQ: LA (Irvine)
Founded: 2019
Funding: $14.5M including $1.5M in 2025, $6M in 2024, $5M in 2022, $2M in 2021 (Crunchbase)
Web visits: 5,000 (April 2026) vs. 8,100 (Aug 2024, SimilarWeb)
Employees: 32 vs. 10 in Aug ’24 (Pitchbook); 16 in Jan ‘24,17 in June ’23
Article citations: 11 (Crunchbase)
Linkedin: 2,000 followers vs 1,000 in Aug ’24 (22 employees vs. 17 in Aug ’24; 18 in June ’23)
No longer accepting new business
Fast (winding down business)
– HQ: San Francisco
– Founded: 2019
– Raised $125M including $102M in 2021 (Crunchbase)
– Website visits: 210,000 (May 2023; SimilarWeb)
– Employees: 400 (Pitchbook), unchanged
– Articles: 110 (Crunchbase)
– Linkedin: 22,300 followers
– Rating: 4.5 (2,870 reviews per TrustPilot)
Note: We excluded PayPal from because they are more of an enterprise solution, and less importantly, was founded in 1998, so a little old/established for a “challenger” list.
