When a client pays you in USDC

The situation

Nikola is a backend developer in Varna. A new client, a small software company that already runs its finances in stablecoins, wants him for a three-month project at 2,500 USDC a month. The contract is fine. Then the client's operations lead sends a short message: "We pay in USDC. Send us your address. Which network?"

Nikola has used crypto a little, but has not received a business payment this way. He has heard stories of coins sent to the wrong network and lost. He also knows the money has to end up in euros in his Bulgarian account, and that his accountant will want to see paperwork. The first payment is due in two weeks.

Where the cost or risk really comes from

Receiving USDC is cheap. The risks are almost all about mistakes and missing records:

• Network mismatch. USDC exists on many blockchains. Ethereum, Base, Arbitrum, Polygon and Optimism share one address format, so an address that looks right can still be on a network the recipient did not expect. Solana uses a different format. A payment on the wrong network can be lost or hard to recover.
• Address errors and tampering. A mistyped address, or malware that replaces the copied address for a lookalike, sends money to someone else. Blockchain transfers cannot be reversed.
• Fake tokens. Anyone can create a token called USDC. Only the contracts published by Circle are real USDC.
• The wrong asset. A client may send a different stablecoin than agreed. It may not be what you can pay out.
• Records. A blockchain payment does not come with an invoice number. Without your own record linking the transaction to the invoice and its euro value, your accountant and the NRA see a transfer without context.
• The cash-out step. Turning USDC into euros has a cost, and selling a crypto-asset has tax consequences under Bulgarian law.

How to handle it

1. Put token and network in the invoice. Write "USDC on Solana" (or another network both sides support) and your wallet address in the invoice and the contract. The xChange.bg wallet supports Solana, Ethereum, Base, Arbitrum, Polygon and Optimism.
2. Copy your address from the app, not from an old message. Open the receive screen, select the agreed network and copy the address shown there.
3. Check it before you send it. Paste it into the crypto address checker to confirm the format and checksum, and compare the first and last characters with what you are about to send.
4. Ask for a test payment. A small amount, for example 5 USDC, on the agreed network. Confirm it arrived before the client sends the rest.
5. Check the token contract. Compare the token's contract address with the list Circle publishes for that network. If it does not match, it is not USDC.
6. Convert what you need. Use send to bank to pay out euros to your own IBAN at 1.25%. The rate and fee are shown before you confirm. Keep the rest as USDC if you prefer.
7. Keep a record for each payment. Invoice number, date, amount in USDC, transaction hash, network, the euro value on the day of receipt (for example at the ECB reference rate) and the payout statement. The crypto tax guide explains the rules for selling crypto-assets. This is not tax advice.

Setup checklist

• xChange.bg account opened and verified
• Network agreed with the client in writing
• Address copied from the app, checked with the address checker
• Invoice template with token, network and address
• Test payment received and confirmed
• Official USDC contract address for your network saved from Circle's list
• Your Bulgarian IBAN saved for payouts
• A simple spreadsheet: invoice, date, USDC, hash, euro value, payout

Worked example

Nikola's first invoice: 2,500 USDC on Solana. The client sends a 5 USDC test, then 2,495 USDC. The client pays the network fees. Nikola pays out 2,000 USDC to his Bulgarian bank and keeps 500. The example uses an illustrative rate of USD 1.15 per euro.

His record for the month: invoice 2026-014, received 2,500 USDC on Solana with two transaction hashes, euro value on the day of receipt at that day's ECB rate, and a payout of 2,000 USDC with its statement. How the fee income is taxed depends on how Nikola works, and whether the sale of the USDC produced a gain or loss depends on the acquisition value his accountant uses. Both questions go to the accountant with this record in hand.

Compared with a bank route, there is no incoming wire fee and no 1.5% on-ramp fee, because the money arrived on-chain. The only xChange.bg fee is the 1.25% on the part he converted.

What this is based on

Circle's developer documentation lists the official USDC contract addresses on each supported network, which is the reference for spotting fake tokens. Solana's documentation and ethereum.org explain how network fees work and why they differ between networks. The National Revenue Agency's crypto-assets page and the Personal Income Tax Act, Article 33, paragraph 3, set out how sales of crypto-assets are taxed and declared, and the NRA page covers record keeping. Fees come from the xChange.bg pricing page: network fee only for receiving on-chain, 1.25% for bank payouts. Nikola, his client and the numbers are illustrative.