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Maric Run Test
Maric Run Test

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Why Testing in Web3 Is Not Like Traditional QA?

When I first switched from Web2 to Web3, I thought,

“It’s just UI and API testing, right?”

But, I realized I had stepped into a completely different world.
Here are the biggest differences that every QA needs to understand before testing blockchain apps.

🔐 1. Immutable Data
In Web2, we can roll back, reset test data, or fix mistakes easily.
In Web3? Not possible.

  • Every transaction is permanent on the blockchain.
  • One small bug in a smart contract can cause real money loss.
  • No "admin" to change data.

💡 Lesson: Be extra careful when testing anything that writes to the blockchain.

🌐 2. Decentralized Architecture
No more single backend with easy logs or debugging.
Web3 systems have many parts:

  • UI: runs in browser
  • Wallet: signs & sends transactions (e.g., MetaMask)
  • Smart Contract: runs on-chain logic
  • Node/Provider: connects to blockchain (Infura, Alchemy...)
  • Subgraph/Indexer: stores & queries blockchain data

💡Lesson: Bugs can happen anywhere in this stack. As a QA, you need to understand the full picture.

3. Gas fee
Every on-chain action costs gas (real crypto, even on testnet).

  • Need ETH (testnet) to run tests
  • Spamming tests = run out of gas = testing stops
  • Performance testing must consider gas cost

💡 Lesson: Plan your tests carefully to avoid wasting resources. And check gas usage in your test cases.

4. Smart Contracts ≠ Normal Backend
Smart contracts cannot be modified after deployment (unless a proxy is used). The logic handling is also very different from the backend API:

💡 Lesson: Don't just check the result. Understand the contract logic too. Sometimes it “works” but is badly designed.

🔄 5. On-chain vs Off-chain Testing
Not all data is on the blockchain.

  • On-chain: balances, transactions, smart contract state

→ Test using explorers, Hardhat, JSON-RPC

  • Off-chain: UI state, indexers, caches

→ Test using Postman, browser tools, etc.

💡 Lesson: UI testing is not enough. Use blockchain tools to see the full picture.

🧩 Final Thought
Testing in Web3 is more than just checking UI or APIs.
It’s about understanding a decentralized system—where bugs can affect real assets, real users, and can’t be undone.

The first step to becoming a good Web3 QA isn’t learning tools — it’s fixing the mindset bug.

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