Interact with QR Coin auctions on Base. Use when the user wants to participate in qrcoin.fun QR code auctions — check auction status, view current bids, create new bids, or contribute to existing bids. QR Coin lets you bid to display URLs on QR codes; the highest bidder's URL gets encoded.
Participate in QR Coin auctions on Base blockchain. QR Coin lets you bid to display URLs on QR codes — the highest bidder's URL gets encoded when the auction ends.
| Contract | Address |
|---|---|
| QR Auction | 0x7309779122069EFa06ef71a45AE0DB55A259A176 |
| USDC | 0x833589fCD6eDb6E08f4c7c32D4f71b54bdA02913 |
Note: The examples below use
https://mainnet.base.org(public RPC). You can substitute your own RPC endpoint if preferred.
Always query this first to get the active auction ID before bidding.
curl -s -X POST https://mainnet.base.org \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","method":"eth_call","params":[{"to":"0x7309779122069EFa06ef71a45AE0DB55A259A176","data":"0x7d9f6db5"},"latest"],"id":1}' \
| jq -r '.result' | xargs printf "%d\n"
# First get the current token ID, then use it here
TOKEN_ID=329 # Replace with result from currentTokenId()
TOKEN_ID_HEX=$(printf '%064x' $TOKEN_ID)
curl -s -X POST https://mainnet.base.org \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","method":"eth_call","params":[{"to":"0x7309779122069EFa06ef71a45AE0DB55A259A176","data":"0xa4d0a17e'"$TOKEN_ID_HEX"'"},"latest"],"id":1}' \
| jq -r '.result' | xargs printf "%d\n"
# Create bid reserve (~11.11 USDC)
curl -s -X POST https://mainnet.base.org \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","method":"eth_call","params":[{"to":"0x7309779122069EFa06ef71a45AE0DB55A259A176","data":"0x5b3bec22"},"latest"],"id":1}' \
| jq -r '.result' | xargs printf "%d\n" | awk '{print $1/1000000 " USDC"}'
# Contribute reserve (~1.00 USDC)
curl -s -X POST https://mainnet.base.org \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","method":"eth_call","params":[{"to":"0x7309779122069EFa06ef71a45AE0DB55A259A176","data":"0xda5a5cf3"},"latest"],"id":1}' \
| jq -r '.result' | xargs printf "%d\n" | awk '{print $1/1000000 " USDC"}'
QR Coin auctions require USDC transactions on Base. Use Bankr to execute these — Bankr handles:
Before bidding, approve the auction contract to spend USDC:
Approve 50 USDC to 0x7309779122069EFa06ef71a45AE0DB55A259A176 on Base
To start a new bid for your URL:
Function: createBid(uint256 tokenId, string url, string name)
Contract: 0x7309779122069EFa06ef71a45AE0DB55A259A176
Cost: ~11.11 USDC
Important: Always query
currentTokenId()first to get the active auction ID.
Example prompt for Bankr:
Send transaction to 0x7309779122069EFa06ef71a45AE0DB55A259A176 on Base
calling createBid(329, "https://example.com", "MyName")
To add funds to an existing URL's bid:
Function: contributeToBid(uint256 tokenId, string url, string name)
Contract: 0x7309779122069EFa06ef71a45AE0DB55A259A176
Cost: ~1.00 USDC per contribution
Example prompt for Bankr:
Send transaction to 0x7309779122069EFa06ef71a45AE0DB55A259A176 on Base
calling contributeToBid(329, "https://grokipedia.com/page/debtreliefbot", "MerkleMoltBot")
| Function | Selector | Parameters |
|---|---|---|
currentTokenId() | 0x7d9f6db5 | — |
auctionEndTime(uint256) | 0xa4d0a17e | tokenId |
createBidReserve() | 0x5b3bec22 | — |
contributeReserve() | 0xda5a5cf3 | — |
createBid(uint256,string,string) | 0xf7842286 | tokenId, url, name |
contributeToBid(uint256,string,string) | 0x7ce28d02 | tokenId, url, name |
approve(address,uint256) | 0x095ea7b3 | spender, amount |
| Error | Meaning | Solution |
|---|---|---|
RESERVE_PRICE_NOT_MET | Bid amount below minimum | Check reserve prices |
URL_ALREADY_HAS_BID | URL already has a bid | Use contributeToBid instead |
BID_NOT_FOUND | URL doesn't have existing bid | Use createBid instead |
AUCTION_OVER | Current auction has ended | Wait for next auction |
AUCTION_NOT_STARTED | Auction hasn't begun | Wait for auction to start |
INSUFFICIENT_ALLOWANCE | USDC not approved | Approve USDC first |
currentTokenId() — Get the active auction IDcreateBid (~11.11 USDC)contributeToBid (~1.00 USDC)💡 Pro Tip: Contributing to an existing bid is cheaper than creating a new one. Check if someone already bid for your URL before creating a new bid.