The short version
Scale: why RedotPay leads
Independent researcher tracking puts RedotPay at $537.9M topped up in September 2026, up from $304.8M a year earlier, which is nearly half of the $1.22B market total that month. Among the challengers, ether.fi is the largest self-custodial program at $128.8M spent, KAST did $213.4M topped up, and Plasma did $25.6M spent. Two honesty notes: the RedotPay and KAST figures are top-up volume (money loaded onto the card), not card spend, so they are not directly comparable to spend figures; and the numbers come from a researcher's tracking, since the industry data provider has no public API.
Custody: the real dividing line
This is the most important table on the page. It decides what happens to your money if the company behind the card has a bad day.
| Card | Custody model | What it means |
|---|---|---|
| RedotPay | Custodial (Fireblocks) | Your crypto sits with RedotPay. PCI DSS 4.0 certified, about $42M insurance cited by reviewers. Convenient, but it is counterparty risk. |
| ether.fi Cash | Non-custodial vault | Assets stay in your own vault on Optimism. Only you authorize transactions; the issuer has no custody or control over wallet contents. |
| Plasma One | Self-custodial smart wallet | You hold your own keys; only you authorize transactions on the Plasma chain. |
| KAST | Company-held balances | Balances sit with KAST's program structure rather than in a wallet you control. Independent researchers describe it as a custodial model; confirm the current terms before loading large amounts. |
Cashback: advertised vs capped reality
RedotPay's standard card pays no cashback at all. Cashback only exists on RedotPay Pro ($12.90/month or $129/year): 3% on Apple Pay and Google Pay purchases, credited in USDs for future spending. Everyone else pays something on the free tier, but every headline rate sits inside a monthly cap.
| Card (entry tier) | Headline rate | Cap | Real earnings on $1,000/mo |
|---|---|---|---|
| RedotPay Standard | 0% | No cashback offered | $0 |
| RedotPay Pro | 3% (Apple/Google Pay only) | Mobile wallets only | $30, minus $12.90/mo fee |
| ether.fi Cash Core | 3% | First $2,000/mo | $30 |
| KAST Standard | 1.5% | First $2,000/mo | $15 |
| Plasma One Lite | 2% | First $500/mo, then 0.1% | $10.50 |
The math favors ether.fi at normal spending: $30 on $1,000 with no annual fee and no mobile-wallet restriction. RedotPay Pro matches the $30 only if all your spending goes through Apple Pay or Google Pay, and the subscription eats nearly half of it at this spend level. KAST's paid tiers go higher (2% on Premium, 3% on Private) but cost $1,000 and $10,000 a year respectively, so they only make sense at very high spend.
Fees compared
| Fee | RedotPay | KAST | ether.fi | Plasma One |
|---|---|---|---|---|
| Card issuance | $10 virtual / $100 physical | Free virtual / $40 physical | $10 virtual / $50 physical (Core) | Free Lite (virtual only) |
| FX markup | 1% default-currency conversion + 1.2% non-default | Check app (not published in our data) | 0.5% Core, 0.25% Luxe, 0% Pinnacle/VIP | 1% Lite, 0.5% Core, 0% Platinum |
| Top-ups | On-chain free; bank card 3%; Binance Pay 1% | USDT on Solana primary path | Bank transfers in 162 countries; crypto deposits | Stablecoin deposits; bank rails vary by tier |
| ATM | Tiered; 3% above $10,000/mo on USD cards | Check app (not published in our data) | $5,000/tx, 5 per 24h, $25,000 daily | Up to $1,000/tx, 3 per 24h, physical only |
Availability
- RedotPay: around 40 unsupported countries including the US, Mainland China, Russia, Iran, and North Korea. If you are in a restricted area you cannot open the app at all. Singapore cards issued by Xfers (StraitsX); Hong Kong cards by Reap.
- KAST: advertised in 190+ countries; ID requirements vary by country. Issued by Third National, a Rain group company.
- ether.fi Cash: bank transfers in 162 countries; physical card ships to 31 US states (no delivery to Belgium or Ireland). Issued by Third National, a Rain group company.
- Plasma One: the provider does not publish a specific country list. Issued via Rain infrastructure with account services by Bridge.
What you give up for RedotPay's convenience
RedotPay earned its scale by being the simplest on-ramp: top up from the app, spend anywhere Visa works, no vaults or keys to think about. Here is the honest price of that simplicity.
Your money is theirs until you spend it
Custodial balances mean you are trusting RedotPay's solvency, security, and compliance. With ether.fi or Plasma One, a company failure does not trap funds that were never in company hands.
No rewards without a subscription
The standard card pays 0% cashback. Every challenger here pays something on its free tier. RedotPay Pro's 3% only applies to Apple Pay and Google Pay purchases, so physical card swipes earn nothing extra.
No DeFi upside
ether.fi offers borrow mode against your vault from 1.43% and KAST pays boosted USD Reserve rates until mid-2027. RedotPay is a spending tool, not a yield venue.
Geographic blind spots
US residents are fully excluded, along with about 39 other countries. If you move to the US, your card stops being an option.
Beyond the card: what else each app does
RedotPay
- P2P payments in 100+ countries
- RedotPay Pro subscription with mobile-wallet cashback and ATM allowances
- In-app crypto purchases and swaps
KAST
- USD Reserve account with boosted rates (8-12%) until mid-2027, then 4%
- Self-custodial earn vaults including USDKY and Gauntlet-curated options
- Tiered Visa lineup from Platinum to Infinite
ether.fi Cash
- Borrow mode: spend against crypto collateral from 1.43% without selling
- 5% cashback on ether.fi Travel bookings plus hotel and flight discounts
- Lounge access, Visa concierge, and global eSIM on higher tiers
Plasma One
- Yield on stablecoin balances through DeFi protocols in the Plasma ecosystem
- AI cashback and airline cashback perks on higher tiers (as shown in the app)
- Free transfers between Plasma One users
The verdict
The beginner who wants simplicity
RedotPay, if your country is supported. Nothing here is easier: top up, tap, done. Just go in knowing the standard card pays no cashback and your balance is custodial, so keep only spending money on it. If you are in the US, RedotPay is not an option at all, which makes KAST or ether.fi the default pick.
The self-custody believer
ether.fi Cash or Plasma One. ether.fi gives you a non-custodial vault plus 3% on up to $2,000 of monthly spend with no annual fee, which is the strongest free-tier package in this comparison. Plasma One Lite is the simplest free entry at 2% on the first $500, with a cleaner upgrade path if you later want zero FX fees.
The rewards maximizer
Do the math on your actual monthly spend. At $1,000 a month, ether.fi Core's $30 beats everything here. At very high spend, KAST Private's 3% with higher caps or ether.fi Pinnacle's $50,000 monthly cap take over, but weigh the $10,000 KAST Private membership against what you will actually earn back. RedotPay Pro only makes sense if nearly all your spending already flows through Apple Pay or Google Pay.
Affiliate disclosure
The links below are referral links. Using them is optional and does not change the price you pay; it may earn us a commission that supports our independent reviews.
Frequently asked questions
Is RedotPay really the biggest crypto card?
By volume, yes. Independent researcher tracking puts RedotPay at $537.9M topped up in September 2026, nearly half of the $1.22B market total that month, up from $304.8M a year earlier. Note the figure is top-up volume (money loaded), not card spend, and it comes from the researcher's tracking since the industry data provider has no public API.
Is RedotPay custodial?
Yes. RedotPay is custodial: your crypto sits with them under Fireblocks custody, not in your own wallet. They cite PCI DSS 4.0 certification and about $42M in insurance coverage in third-party reviews. That makes it convenient but means you carry counterparty risk. Keep spending money there, not savings.
Which card pays the most cashback on $1,000 a month?
Of these four, ether.fi Cash on the free Core tier pays the most at that spend: 3% on the first $2,000 of monthly spend, which is $30 on $1,000. KAST Standard pays 1.5% ($15), Plasma One Lite pays 2% on the first $500 then 0.1% (about $10.50), and RedotPay's standard card pays nothing; only the $12.90/month Pro plan pays 3%, and only on Apple Pay and Google Pay purchases.
Can US residents get RedotPay?
No. RedotPay's help center lists around 40 unsupported countries and regions, including the United States, Mainland China, Russia, Iran, and North Korea. If you are physically in a restricted area you cannot access the app at all. KAST advertises 190+ countries and ether.fi supports bank transfers in 162 countries, so check each card's list for your country.
What do I give up by choosing RedotPay over a self-custodial card?
Custody. With RedotPay your balance is held by the company under Fireblocks custody; with ether.fi or Plasma One your assets stay in wallets or vaults you control, so a company failure does not trap your funds. You also give up cashback unless you pay for Pro, and you give up the DeFi features (borrow mode, yield vaults) the challengers bundle in.
Do any of these cards require KYC?
Yes, all of them. Every card here runs on regulated Visa or Mastercard rails and requires identity verification. Self-custody describes where your assets sit, not whether you verify your identity. No legitimate card issuer skips KYC on the card itself.