Because the service was checking that the card is real. When you add a Blomo card to a service, the service usually sends a check for zero, sometimes for one dollar, and often asks for a 3-D Secure confirmation at the same moment. The check asks the card’s issuer one question — is this card valid? — and is not a purchase. If the service does not count that amount towards a payment, it is returned to your Blomo balance. Blomo does not publish a time for that return.
Two kinds of check, one purpose
A service that stores your card — a subscription, an ad account, a marketplace, a phone wallet — wants to know the card works before it relies on it. There are two common ways to ask.
A zero-amount check. Visa calls this Account Verification and describes it, in its own developer documentation, as “Account Verification (also known as a $0 authorization)”, used to “determine if a particular cardholder’s account is valid and in good standing” (Visa Developer, Payment Account Validation, read on 26 September 2026). The same page gives the typical occasions: “validating an account before loading it into a digital wallet or card-on-file repository” — which is exactly what adding a card to a service is. It also states: “All Visa issuers support Account Verification requests.”
A small-amount check. Some services use a real amount instead, usually a dollar or its equivalent. Google Ads describes its own version plainly: “In some cases, Google Ads may test a small charge on your card to make sure it’s valid. You won’t actually pay that test amount, but the amount of your payment will be reduced by it.” Its example is a $300 payment that becomes a $1 test charge and $299 for ads (Google Ads Help, read on 26 September 2026). In that case the dollar is part of what you meant to pay anyway, so there is nothing to return. That is one merchant’s method; other services do not count the check towards any payment.
Which of the two a service uses is the service’s choice. Blomo does not choose it and cannot tell you in advance which one a given service runs.
What happens on a Blomo card
| What you see | What it is | What happens to the money |
|---|---|---|
| A check for 0 | Validity check, no amount | Nothing leaves the balance |
| A check for 1 dollar or its equivalent | Validity check with a small amount | Returned to the Blomo balance, unless the service counts it towards a payment |
| A 3-D Secure request | The service asking you to confirm it is you | No money involved |
Blomo’s own description of card linking is the table above: most often the check is for zero, sometimes for one dollar; it is a check that the card is valid, often together with a request to confirm 3-D Secure; and an amount the service does not count towards a payment is returned to the balance. Blomo does not state a time for that, and this article does not invent one.
One more thing about a one-dollar check on a card that is not in dollars. No Blomo card is issued in USD, and the balance itself is in USDT. The amount taken off the balance for a dollar check on a euro, zloty, pound or rupiah card follows the rate of that currency, so the figure you see may not be a round number.
The 3-D Secure request
A service adding your card may ask for 3-D Secure confirmation at the same time as the check. Blomo cards support 3-D Secure, and the confirmation request appears in the Blomo app and in the Blomo Telegram bot. Keep the service’s page open, confirm in Blomo, and the service gets its answer.
Only confirm a request you started. A 3-D Secure prompt for a card you are not adding right now, or for an amount you do not recognise, is a reason to stop and check what the card is being used for — someone has your password: what to do now covers the order of steps.
When the check itself fails
A zero check asks whether the card is valid. A one-dollar check also needs that dollar to be available at the moment it arrives. Two Blomo-specific situations make it unavailable:
- An empty or near-empty balance. The balance is in USDT, and the card spends from it.
- An open card order. From the moment you order a new card until it is activated, your whole available balance is held and cannot be spent (ordering a second card holds your balance). Adding an existing card to a service during that window can fail a one-dollar check for the same reason any payment would fail. A top-up made after the order is not held.
And a check can fail before any of that: some services refuse a card from its leading digits alone, without asking the issuer anything. That is a merchant rule rather than a check result, and a bigger balance does not change it — what a BIN is and why a shop declines your card explains the difference.
What this is not
A card check is not the same thing as a pre-authorisation for a whole booking. A hotel or booking site can place a temporary hold for roughly the cost of the stay, which is a different size of problem for a card funded from a balance. That is covered separately in booking a stay: pay now or at the property?
Questions people actually ask
Why was I charged $1 when adding my card?
The service was checking that the card is valid. Some services check with a zero amount, some with a small amount such as one dollar. On a Blomo card, if the service does not count that amount towards a payment, it is returned to the Blomo balance.
What is a $0 authorization?
A validity check with no amount. Visa’s developer documentation describes Account Verification as “also known as a $0 authorization”, used to determine whether an account is valid and in good standing, for example before a card is stored for later payments.
How long until the dollar comes back?
Blomo does not publish a time for it. What Blomo states is that a check amount the service does not count towards a payment is returned to the balance.
Why did I get a 3-D Secure request when I only added the card?
Services often ask for 3-D Secure confirmation when a card is stored. Blomo cards support 3-D Secure; the request appears in the Blomo app and in the Blomo Telegram bot.
Why did the check fail when the card works elsewhere?
Either the balance could not cover a one-dollar check at that moment — an open card order holds the whole balance until the new card is activated — or the service refused the card from its number before asking the issuer anything.
Read on
- Fees, in full — Every fee Blomo charges, card by card.
- Why does Google Ads refuse a prepaid card? — One merchant’s card check, and how each Blomo card is registered.
- Ordering a second card holds your balance — Why a check can fail while a card order is open.
- Account security — Two-factor, card data and what Blomo stores.