--- url: /academy-handbook/foundation/week-1/part-8-the-user-journey.md --- # Week 1 · Part 8 — How it all connects: one user journey You now have seven pieces. This is where they become one picture. ::: important This page is a preview, not a lesson Roughly half the steps below are taught in Weeks 2 and 3. Each is marked and linked to where it is covered. You are **not** expected to understand them yet. You are expected to finish the week able to say *"I know what that step is for, and I know which week explains it."* ::: ::: warning You will not do this journey It involves real money and real risk, and nothing in this programme requires either. It is here to show how the pieces fit — nothing more. ::: ## Learning objectives * Trace one possible path from a bank account to an on-chain position and name each step * Identify which steps you already understand and which are still ahead * Explain, at each handover, what changes about who you are trusting * Point to the week that covers each step you have not met yet ## Core ### The journey This is one deliberately complex example, not the sequence every Web3 user follows. A bridge appears only when value needs to move between networks, and an explorer or dashboard is for observing activity rather than receiving assets. ```mermaid flowchart TD F["Fiat
money in a bank"] C["Centralised exchange
✅ Part 5"] U["USDC
stablecoin · ✅ Part 5"] W["Self-custody wallet
✅ Part 6"] E["Ethereum — L1
Base — Ethereum L2
→ Week 2"] B["Bridge
only if moving networks
→ Week 2"] D["DEX / protocol
→ Week 3"] P["DeFi application
→ Week 3"] E2["Another network
after bridging"] X["Explorer / Dune
observe activity
✅ Part 7 · → Week 4"] F --> C --> U --> W --> E E --> D --> P E --> B --> E2 --> P E -.-> X D -.-> X P -.-> X ``` ✅ means you have covered it. → means it is ahead of you. ### Step by step Watch the **"what you are trusting"** line at each handover. Read the rows as branches in the example, not as a mandatory queue. | Step | What happens | What you are trusting | |---|---|---| | **Fiat → exchange** | Money moves from a bank into an exchange account. A normal regulated relationship: KYC, an account, a company holding your funds | The exchange, **entirely**. You have a claim, not an asset | | **Exchange → USDC** | Fiat converted to a stablecoin. Dollar value that moves at blockchain speed | The exchange, **plus Circle** — the issuer holding reserves. A new assumption, quietly added | | **Exchange → wallet** | Withdrawn to an address you control. Custody moves from a company to a person | **You control custody.** The exchange no longer controls the wallet, but token-level controls may still exist — for example, a stablecoin issuer may be able to freeze its token | | **Wallet → chain** | Assets sit on Ethereum, or on **Base**, an Ethereum L2 that handles activity separately while relying on Ethereum for important settlement/security. Lower fees are a common benefit; the route does not require a bridge | The network, and the L2's operators → [Week 2 Part 5](../week-2/part-5-l1-l2-and-bridges.md) | | **Bridge, only when needed** | Moving value between networks. Chains cannot natively see each other | Source chain + destination chain + **the bridge mechanism** → [Week 2 Part 5](../week-2/part-5-l1-l2-and-bridges.md) | | **DEX** | Swapping assets through contracts, from your own wallet, no account | Your wallet + the DEX contracts + each token's contract → Week 3 | | **DeFi protocol** | Depositing into a lending market or pool — finance by programs, not institutions | All the above + this protocol's contracts + its **oracle** + its economic design → Week 3 | | **Explorer / Dune** | A block explorer or dashboard lets you observe and analyse on-chain activity; it is not the destination of the assets | The explorer's record; Dune's indexing and definitions if you use its dashboard → [Part 7](./part-7-your-first-transaction.md), Week 4 | ::: warning Bridges deserve early attention Bridges have historically been a major source of large crypto exploits — worth understanding even before you know how they work. ::: ### The thing to actually take from this Read the trust column downward and notice the shape. | Stage | Trusting | |---|---| | Exchange | The exchange | | USDC | Exchange + issuer | | Self-custody | **Yourself** + issuer | | Chain / L2 | The network; if using an L2, also its additional operators/controls | | Bridge | Two chains + bridge mechanism | | DEX | Wallet + several sets of contracts | | DeFi protocol | All of the above + oracle + economic design | \==**Trust assumptions change as you move through the stack.**== They can increase, decrease or shift depending on the path. In this example, each extra component adds another assumption. Moving to self-custody did not remove trust — it moved it onto you, and onto the software you interact with. Each additional protocol adds assumptions rather than removing them. ::: important The single most useful sentence in Week 1 **==Web3 does not eliminate trust. It changes and redistributes trust assumptions.==** [Week 2 Part 6](../week-2/part-6-trust-and-risk-map.md) turns this into a tool you can apply to anything. ::: ### Transaction lifecycle: how a blockchain actually runs The journey above followed one user's choices. Now follow the machine underneath those choices. This is a generic model: different chains use different rules, but the same broad questions keep appearing. ```mermaid flowchart TD U["User creates an instruction
or transaction"] W["Wallet signs it"] P["Transaction is submitted
and propagated"] C["Nodes check basic validity"] S["Proposer / block producer
selects valid transactions"] B["A block is proposed"] V["Other participants verify
the block and resulting state"] K["Consensus determines
the accepted history"] Q["Shared state is updated"] R["Wallets, explorers and applications
read the new state"] U --> W --> P --> C --> S --> B --> V --> K --> Q --> R ``` | Stage | What happens in this generic model | Week 1 connection | |---|---|---| | ==**Create and sign**== | A user describes an action, and a wallet authorises it with the account's key | [Part 6](./part-6-wallets-and-accounts.md) | | **Propagate and check** | The request travels to network participants, which reject requests that do not follow the chain's basic rules | [Part 7](./part-7-your-first-transaction.md) | | **Propose a block** | A chain-specific proposer or block producer chooses valid transactions for a candidate block | [Part 3](./part-3-consensus.md) | | ==**Verify and agree**== | Other participants check the block and its result; consensus determines which valid history the network follows | [Part 2](./part-2-how-shared-state-works.md) · [Part 3](./part-3-consensus.md) | | **Update and read** | Once accepted, the shared state includes the result. Wallets, explorers and applications can query it | [Part 2](./part-2-how-shared-state-works.md) | ::: important Week 1 pieces now connected Part 2 explains the shared record. Part 3 explains how participants choose the accepted history. Part 4 explains why some participants do the work. Part 6 explains who can authorise an action, and Part 7 lets you watch one transaction make the journey. ::: ### A separate question: who is paid? Depending on the chain's design, miners, validators or other block producers may receive protocol rewards and/or transaction fees. The amount and mechanism are chain-specific; payment is an incentive for participating, not part of the definition of every block. \==This is the system-level view to keep: an instruction is authorised, carried through the network, checked, included under the chain's rules, and reflected in shared state.== The details of how a chain selects and finalises blocks are what [Part 3](./part-3-consensus.md) examines. ## Landscape * **On-ramp / off-ramp** — converting between fiat and crypto in either direction. The service handling the conversion adds its own fees, limits and custody risk * **Layer 2** — a network such as Base that handles activity separately while relying on a base chain such as Ethereum for important settlement or security (Week 2). It adds another system and therefore another set of trust assumptions * **Wrapped asset** — a token representing an asset from elsewhere ([Part 5](./part-5-crypto-asset-map.md)). Its value depends on the mechanism that links it to the underlying asset * **Slippage** — the gap between the price you expected on a swap and the one you got. Thin liquidity or a large trade can make the gap wider * **Liquidity pool** — pooled assets a DEX trades against (Week 3). More liquidity usually makes larger trades easier to execute without moving the price as much * **Oracle** — a service supplying external data to contracts (Week 3). If the data is wrong or manipulated, the contract can make a wrong decision * **Yield** — return from lending or providing liquidity. It is compensation for a risk; the useful question is which risk pays it ## Worked example The same journey as a decision rather than a diagram. A student in Singapore wants to send S$500 to a family member abroad and has heard stablecoins are faster. | They do | They gain | They take on | |---|---|---| | Buy USDC on a licensed exchange | A dollar value that can move quickly | Exchange custody; issuer reserves | | Withdraw to their own wallet | They control custody; token-level issuer controls may remain | Full responsibility for keys | | Send to the recipient's address | Can settle quickly, with low on-chain fees on some networks | Wrong address means it is gone. No reversal | | Recipient converts to local currency | Done | Their local exchange, their local rules | It can be faster or cheaper than four correspondent banks, depending on the network, on/off ramps and conversion route. It also has no error correction anywhere in the chain, several new counterparties, and two jurisdictions' regulations — [Week 0 Part 5](../../getting-started/regulatory-awareness.md). ::: important Whether that trade is worth making depends entirely on the situation Noticing that it **is a trade** — rather than a straightforward upgrade — is what this week was for. ::: ::: details Further exploration — optional, not assessed * [ethereum.org — Layer 2](https://ethereum.org/layer-2/) — a preview of Week 2 * [ethereum.org — Decentralized finance](https://ethereum.org/defi/) — a preview of Week 3 * [ethereum.org — Bridges](https://ethereum.org/developers/docs/bridges/) — including a frank treatment of the risks ::: ::: details Sources and attribution * [ethereum.org — Stablecoins](https://ethereum.org/stablecoins/) — Reuse (CC BY 4.0), adapted * [ethereum.org — Decentralized finance (DeFi)](https://ethereum.org/defi/) — Reuse (CC BY 4.0), adapted * [ethereum.org — Bridges](https://ethereum.org/developers/docs/bridges/) — Reuse (CC BY 4.0), adapted * [ethereum.org — Layer 2](https://ethereum.org/layer-2/) — Reuse (CC BY 4.0), adapted * [Web3 Internship Handbook](https://web3intern.xyz/zh/blockchain-basic/) — Reuse (permission granted); lifecycle structure used as inspiration and rewritten for this handbook * [Base documentation](https://docs.base.org/) — Link, referenced for the L2 example *Named products are illustrative, not recommendations. Nothing here is financial advice.* :::