This page is the technical reference for Monero in Payfim: the two verification modes, what each field expects, and where setups tend to fail. For the broader question of whether Monero suits your business and how to present it to customers, read accepting Monero payments as a merchant.
Why does Monero need a view key when other coins do not?
On Bitcoin or Ethereum anyone can look up an address and see what arrived. Monero is built so that outsiders cannot. Amounts are hidden, and each payment goes to a one-time output that cannot be linked to your address by an observer. To detect a payment, software must scan the chain with your private view key.
Monero's own documentation describes what that key does: sharing a view key allows access to view every incoming transaction for that address. It cannot move funds. Spending requires the separate spend key, which Payfim never asks for.
Explorer mode or RPC mode?
| Explorer + private view key | Your monero-wallet-rpc | |
|---|---|---|
| Admin label | Block explorer + private view key - easiest | My monero-wallet-rpc (view-only wallet) - most private |
| What you run | Nothing extra | A view-only wallet RPC reachable by the gateway |
| Where payments go | Your primary address, with a unique amount per invoice | A fresh subaddress per invoice |
| Who sees your view key | The explorer instance you choose | Only your own server |
| Detection window | The last 5 blocks (about 10 minutes) plus the mempool | Your wallet's history of incoming transfers, including the mempool |
Explorer mode is quicker to set up. RPC mode is the better choice if you want your view key to stay on infrastructure you control, and because each invoice gets its own subaddress, the amount does not need a unique fraction to match the order.
Explorer mode: step by step
- In your Monero wallet, find your primary address (starts with
4, 95 characters) and the private view key (64 hexadecimal characters). - In Payfim, open Wallets & coins and paste the address into the Monero row.
- Under Blockchain APIs → Monero (XMR), set Verification method to the explorer option, paste the private view key, and set the Explorer URL to an onion-monero-blockchain-explorer instance you trust (the field suggests
https://xmrchain.net). - Save both forms, switch Monero on, and press Test.
Payfim rejects a view key that is not exactly 64 hex characters, which catches the most common copy-and-paste slip.
RPC mode: step by step
- Create a view-only wallet from your primary address and private view key, and run
monero-wallet-rpcwith it on a server you control, connected to a Monero node. - Protect the RPC with a username and password (Payfim uses HTTP digest authentication) and, ideally, HTTPS.
- In Blockchain APIs → Monero (XMR), choose the wallet RPC method and fill in Wallet RPC URL (for example
https://your-node:18083/json_rpc), RPC user and RPC password. - Paste your primary address in the Monero row, switch it on, save, and test.
From then on, every invoice that selects XMR gets its own subaddress, starting with 8, created in your wallet.
Fees, timing and confirmations
Monero targets a block every 2 minutes. Payfim's default is 2 confirmations, so most payments move to paid within several minutes. Fees depend on transaction size and the priority the sender picks; OpenChainBench measured a median transfer fee of a few US cents in late September 2026.
Separately, Monero wallets usually keep newly received funds locked for about 10 blocks (roughly 20 minutes) before they can be spent. That affects when you can move the coins, not when Payfim confirms the order.
On the checkout page, the QR code uses a monero: payment link that includes the amount, so most Monero wallets fill in both fields when the customer scans.
Where Monero setups go wrong
- Cron not running (explorer mode). The explorer check only looks at the last 5 blocks and the mempool, roughly 10 minutes of history. If the gateway's cron stops for longer than that while an invoice is open, the payment can fall outside the window and needs to be matched by hand. Keep the cron on its every-minute schedule; see the cron guide.
- Self-signed certificate on the RPC. Payfim verifies TLS certificates when it calls an HTTPS wallet RPC URL. Use a valid certificate.
- Address and view key from different wallets. The connection can look healthy while no payments are ever found. Copy both from the same wallet.
- Subaddress pasted as the main address. In explorer mode, use the primary address that begins with
4. - Refunds. You cannot see where a payment came from. If you need to refund, ask the customer for an address.
Rules on privacy coins differ by country and by the exchanges you use. If this matters for your business, speak with a qualified professional.
Whichever mode you pick, run a test payment from a separate wallet before going live and confirm the invoice reaches paid.
Related
How Payfim protects keys and the admin area is covered on the security page. Monero works in every module, including FOSSBilling and Paymenter.
Sources
Third-party facts were checked on the date shown above. Prices and features of other services change - always confirm on their official pages.