The wrong card, every time.
Saturday's $84.20 grocery order went on the 1.5% card saved in your assistant. Your 4% grocery card sat in your wallet. That one order left $2.11 on the table.
1.5% → $1.264% → $3.37
One card for your AI. Every card you own behind it.
Put a Backstop card in the assistant you already use. When it buys something, we charge whichever of your cards earns the most on that purchase, hold it to limits you set, and keep the record until the return window closes.
Free during early access · Online purchases only · The card holds no balance
If your AI shops for you today, it pays with whichever card you typed in once.
It uses that card for everything. The card has no limits of its own. And the receipts end up in a chat.
No limits of its own.
A card can't tell a $24.99 phone case from a $1,100.00 phone. It approves whatever your assistant submits, up to your credit limit, and you find out on your statement.
$24.99 APPROVED$1,100.00 APPROVED
Receipts in a chat log.
When the order shows up cracked, the record of what was bought, from whom and on which card is in a conversation from three weeks ago.
Search chats: 'headphones' · 14 results
You spent years learning which card to use where. Your assistant is starting from zero.
So give it a card of its own.
Each assistant gets its own Backstop number. The number tells us who is paying, so everything follows the card: its limits, the stores it may use and its purchase history. Close a card, and that assistant is cut off everywhere at once.
Examples
backstopVIRTUAL · ONLINE ONLY•••• •••• •••• 4417CLAUDEGROCERIESVALID THRU 10/29
$150 a week. Grocery stores only.
backstopVIRTUAL · ONLINE ONLY•••• •••• •••• 4417CHATGPTHOUSEHOLDVALID THRU 10/29
$200 a purchase. $500 a month. No travel or gambling.
backstopVIRTUAL · ONLINE ONLY•••• •••• •••• 4417GEMINIONE TRIPVALID THRU 10/29
One purchase, up to $900. Closes after use.
Set up once, in three steps.
Add the cards you already carry.
Backstop charges them for you, so they live in your Backstop wallet, like any other wallet.
Write the rules in a sentence.
'ChatGPT can spend up to $200 a purchase and $500 a month, but not on travel.'
Put the card in your assistant.
Save it in the assistant's payment settings, or paste it at checkout. To your assistant, it is an ordinary card.
What happens in the two seconds after your AI taps Pay.
One grocery order, played at quarter speed.
00:00.00
Your AI taps Pay at Greenline Grocery.
Frame 1 of 6
EXAMPLE · CHECKOUT
Greenline Grocery
Order total $84.20
Pay with card ··4417
00:0000:3000:6001:1001:8002:40
00:00 · Frame 1 of 6
Your AI taps Pay at Greenline Grocery.
00:30 · Frame 2 of 6
The charge reaches Backstop. The card number tells us who is paying.
00:60 · Frame 3 of 6
Your rules check out.
01:10 · Frame 4 of 6
Your cards are scored for this purchase.
01:80 · Frame 5 of 6
Backstop charges your Grocery card. Your statement shows BKSTP*GREENLINE GROCERY.
02:40 · Frame 6 of 6
Approved. Your AI sees a normal payment. You get one line.
Example timings. The card network gives Backstop a few seconds to answer. If your first card declines, we try the next best card inside the same window.
A month of AI purchases, paid two ways.
Same seven purchases, same wallet. One column uses the card saved in the assistant. The other uses Backstop.
| Purchase | Amount | Saved card, 1.5% | Backstop's pick | Earned with Backstop |
|---|---|---|---|---|
| Groceries, Greenline | $84.20 | $1.26 | Grocery ··8812, 4% | $3.37 |
| Takeout, Harbor Thai | $62.75 | $0.94 | Grocery ··8812, 3% | $1.88 |
| Birthday gift | $48.00 | $0.72 | Online ··5530, 3% | $1.44 |
| Drugstore order | $18.50 | $0.28 | Everyday ··0921, 1.5% | $0.28 |
| Groceries, Greenline | $91.35 | $1.37 | Grocery ··8812, 4% | $3.65 |
| Train tickets | $126.00 | $1.89 | Travel ··3388, 3% | $3.78 |
| Phone case | $24.99 | $0.37 | Online ··5530, 3% | $0.75 |
| Total | $455.79 | $6.83 | $15.15 |
$8.32 more this month. About $100 a year.
When the card you already saved is the best one, like the drugstore order, Backstop uses it.
Example wallet: a 1.5% everyday card; a card earning 4% at grocery stores and 3% on dining; a 3% travel card; a 3% online-shopping card. Assumes each issuer posts the purchase under the store's category. Where it doesn't, that purchase earns base rate and its record says so. Points counted at 1¢.
Run it with your wallet
With the card it has now: $54.00 a year.
With Backstop: $111.60 a year.
$57.60 more a year
The card it has now is already your best for this mix. Backstop would still give your AI limits and a record.
Counts points at 1¢, assumes category posting and ignores bonus caps. Your real numbers depend on your issuers.
When it goes over your limit, you get asked first.
Your AI found the headphones you wanted: $320.00 at Northway Audio. Its limit is $200 a purchase.
Backstop first hears about a purchase at the moment the card is charged, so there is no room for a pop-up mid-checkout. Instead it declines, asks you, and lets the retry through if you say yes. Assistants already know what to do with a declined card: they tell you, or they try again.
BACKSTOP · PURCHASE HELD
Your AI tried to spend $320.00
Northway Audio · over your $200 limit · declined for now
APPROVED ONCE: $320.00 on Online ··5530 · Earned $9.60. Approve once opens a 15-minute window for the retry. Your $200 limit stays.
RAISE LIMIT: Limit per purchase $400.00. New limit: $400 a purchase.
DECLINED: Nothing was charged.
Rules you can put on any card
A cap per purchase, per week or per month
Stores and categories it may use, or may not
A second approver for anything over an amount you choose
A single-use card for one job
A ceiling on purchases per hour
Close the card, and its next charge is declined at the network
One record, from checkout to the end of the return window.
Every purchase your assistant makes gets one record: what it bought, which card paid, what it earned and what protections came with that card. We remind you before a return window closes. Refunds go back to the card that paid, so your rewards stay correct.
Northway Audio
Bought by Your AI · Oct 31 · Approved by you
- Paid with
- Online ··5530 (3% online shopping)
- Earned
- $9.60
- Statement
- On your statement: BKSTP*NORTHWAY AUDIO
- Returns
- Return window: closes Nov 30 (store policy)
- Protection
- Card protection: extended warranty, if your card offers one
- Oct 31 · Declined, then approved by you
- Nov 26 · Reminder: return window closes in 4 days
- Nov 27 · Returned. $320.00 refunded to Online ··5530. Your issuer takes back the $9.60. REFUNDED
Wrong card after all? Move a purchase to another card for up to 30 days.
The fine print, in large print.
Is this another credit card I have to pay off?
No. The Backstop card has no bill and holds no money. Every purchase lands on a card you already own and is paid with that card's statement.
Will my issuer treat it as a cash advance?
That's the right question, and we answer it with our own money. Before a card can be added, we charge one of ours from the same issuer and read the statement. Each card in the app is marked Confirmed, Testing or Not yet.
Do I still get my category bonuses?
When your issuer posts the charge under the store's category, yes. When it doesn't, or when the assistant's platform is the seller, that purchase earns your card's base rate, and its record tells you so.
Do you pick the card that pays you more?
No. We pick the card that earns you the most. If two cards earn exactly the same, a partner fee can break the tie, and every purchase shows why its card was picked.
How is it free?
Card issuers pay us when assistants send them spending. Some stores fund offers on the card. And if you keep buying in a category none of your cards rewards, we may suggest one, clearly labeled, and earn a referral fee if you open it.
Which assistants does it work with?
Ones that pay with a card you give them, saved in their settings or typed at checkout. That includes ChatGPT, Claude, Gemini, Perplexity and Copilot. Nothing changes on the assistant's side; to it, this is an ordinary card.
Can I use it in a store?
No. Backstop is only for purchases your assistant makes online. Keep your own cards for the register.
What does Backstop see?
For purchases on a Backstop card: the store, the amount, the category and the time. Not the rest of your spending, and not what was in the cart.
We tried it on our own cards first.
Before any of your cards can be added, we charge one of ours from the same issuer, wait for the statement and write down what happened: did it post as a purchase, under which category, and what did it earn?
First round in progress. Results go here as statements post.
Last updated 2026-10-29.
Two brothers. A credit desk and a rates desk.
Shaun Maher is a high-yield credit research analyst. Brandon Maher trades rates, where a swap has two legs that must settle together. Every Backstop purchase works the same way: the charge your assistant makes and the charge we place on your best card, tied to one record.
We studied math at [Princeton and Columbia]. We started Backstop when our own assistants began buying things and we didn't like how they were paying.
Write to us: founders@[domain]
Photo coming
Photo coming
Get a card for your AI.
Early access is free. Tell us which assistant you use and which cards you carry. We'll send your card once your issuers are confirmed.
You're on the list.
We'll write when your AI's card is ready. If you have a question a points person would ask, reply to the confirmation email.