Best Mobile Card Readers & Tap-to-Pay Processors
Mobile card acceptance has changed twice in the last five years: first when Square turned smartphones into terminals, again when Apple and Android added native Tap-to-Pay so the phone itself becomes the reader with no hardware required. The right pick depends on volume and integration needs. Below ~$5K/month, simplicity and zero monthly fee win. Above that, the per-percentage cost matters and a flat-rate processor with an interchange-plus upgrade path makes sense.
- 1Square7.7/10
Free POS plus flat-rate processing — popular but rarely the cheapest.
Pricing: 2.6% + 10¢ (in-person)Contract: month-to-month✓ Free POS, free reader, no monthly fee, no contract✗ Flat-rate is expensive past ~$10–15K/mo in card volume - 2Stripe8/10
Developer-first online payments with transparent flat-rate pricing.
Pricing: 2.9% + 30¢ (online)Contract: month-to-month✓ Best-in-class developer documentation and APIs✗ Flat-rate is expensive once you cross ~$15K/mo in volume - 3SumUp7/10
European-rooted mobile card reader competing with Square in micro-merchant segment.
Pricing: 2.6% + 10¢Contract: month-to-month✓ Cheap entry hardware ($39)✗ Smaller US ecosystem than Square - 4GoDaddy Payments7.2/10
Bundled payments for merchants already running a GoDaddy website or store.
Pricing: 2.3% (in-person) / 2.3% + 30¢ (online)Contract: month-to-month✓ Cheaper rate than Stripe / Square for most merchants✗ Locked into GoDaddy ecosystem - 5Helcim8.7/10
Interchange-plus pricing with no monthly fee — best-kept secret in SMB processing.
Pricing: Interchange + 0.4% + 8¢ (in-person)Contract: month-to-month✓ Interchange-plus pricing with PUBLIC rates — extremely rare✗ Smaller hardware lineup than Square or Clover - 6Shopify Payments7.2/10
Bundled with Shopify storefronts — penalty fees if you use anything else.
Pricing: 2.4%–2.9% + 30¢ (online, varies by plan)Contract: month-to-month✓ Native to Shopify — zero setup friction✗ Effectively forced — third-party processors get penalty surcharge - 7PayPal (Braintree)6.5/10
Ubiquitous checkout — convenience at a premium rate.
Pricing: 3.49% + 49¢ (PayPal Checkout)Contract: month-to-month✓ Trusted brand boosts checkout conversion✗ 3.49% + 49¢ standard rate is the highest among major processors
Bottom line
For a brand-new mobile operator, Square is the default — the reader is free, the app is best-in-class, and the rate is fair until you scale. SumUp and GoDaddy Payments are credible challengers with slightly lower rates for very low-volume operators. Helcim's mobile app is the only true interchange-plus mobile option and the right pick once volume crosses ~$10K/month. Apple Tap-to-Pay (iPhone) and Android Tap-to-Pay are now supported by Square, Stripe, and Helcim — no extra hardware needed.
Head-to-head comparisons
Direct comparisons between the top-ranked processors on this list.
Fees that affect this category
Definitions, typical ranges, and how to negotiate them.
- Effective Rate1.80% (best-case low-risk) to 4.00%+ (poorly-priced tiered)
- Monthly Fee$0 (Stripe/Square/Helcim) to $199 (high-tier subscription like Stax)
- Interchange Downgrades0.20%–0.80% extra cost per downgraded transaction
- Level 2 / Level 3 ProcessingSaves 50–100 basis points on commercial cards
- ACH vs Credit Card Processing$0.25 to $1.50 per ACH (or 0.5%–1% capped)