Update README.md

README.md

@@ -14,3 +14,18 @@ Token transfers on EThereum are expensive and slow. Now if L2s comes to rescue,
 2. **Signature Exchanges**: Users exchange digitally signed messages or transactions that represent changes in their wallet balances. These messages are cryptographically secure and can be verified by the blockchain when needed.
 3. **Validation and Security**: The signatures ensure the security and authenticity of transactions without the need for immediate on-chain validation. This method speeds up transactions and reduces the load on the blockchain.
 4. **Transparency and Security**: While off-chain transactions are private between involved parties, the final settlement on the blockchain ensures transparency and immutability, providing a secure audit trail of transactions.
+
+## Useful links
+
+### Subgraph
+- Zkevm 1442 : https://thegraph.com/studio/subgraph/w3pay-1442/playground
+- Mumbai : https://thegraph.com/studio/subgraph/w3pay-80001/playground/
+- Celo : https://thegraph.com/studio/subgraph/w3pay-44787/playground
+
+
+### Contract
+- Scoll: https://sepolia-blockscout.scroll.io/address/0x8bEAaa641B1Da8190CB6731141fE3B8F9eb68a01
+- ZKevm: https://testnet-zkevm.polygonscan.com/address/0x626C1Ce3d2BE90D0FE8C48462A756D129A9A6393#code
+- Zeta: https://explorer.zetachain.com/address/0x8bEAaa641B1Da8190CB6731141fE3B8F9eb68a01
+- Mumbai : https://mumbai.polygonscan.com/address/0x21FC5cA746F39D93CFA8421B424696640f838716#code
+- Arbitrum : https://goerli.arbiscan.io/address/0x8bEAaa641B1Da8190CB6731141fE3B8F9eb68a01#code