Tokens and digital ownership
Begin with “Tokens, NFTs and allowances” and work toward “Token interface practice set”. Each available lesson includes a visual explanation and a quick knowledge check.
Read in order or choose a topic below. Completion marks stay in this browser. All 20 lessons in this track are available.
- 01
Tokens, NFTs and allowances
Contracts keep ownership records; standards make them easier to use.
6 MIN READ - 02
How ERC-20 balances are recorded
A token contract defines how an account’s quantity is represented.
3 MIN READ - 03
Understand transfer and transferFrom
Moving your own tokens and spending with permission use different interfaces.
3 MIN READ - 04
Read an allowance
Identify the owner, spender, token and network behind the number.
3 MIN READ - 05
Approve zero and allowance changes
Changing a standing permission requires attention to ordering.
3 MIN READ - 06
The ERC-20 decimals convention
A metadata method helps applications format a raw token integer.
3 MIN READ - 07
What makes an NFT unique?
A token ID distinguishes an item within its contract’s collection.
3 MIN READ - 08
ERC-721 ownership and token IDs
A standard ownership query names one individually tracked token.
3 MIN READ - 09
ERC-1155 multiple token types
One contract can manage balances for several item IDs.
3 MIN READ - 10
Metadata and token ownership differ
A token’s owner record and its descriptive data are separate claims.
3 MIN READ - 11
Where NFT images can live
The token may point to media hosted somewhere else.
3 MIN READ - 12
Onchain versus offchain metadata
Find which parts of a description depend on the chain and which depend on another service.
3 MIN READ - 13
What does a token standard guarantee?
An interface specification supports interoperability, not universal safety.
3 MIN READ - 14
Why token names are not identities
Names and symbols can be reused by unrelated contracts.
3 MIN READ - 15
Wrapped ETH explained
A contract representation can make ETH usable through a token-style interface.
3 MIN READ - 16
Stablecoin mechanisms at a glance
A target price depends on a design, not on the word stable.
3 MIN READ - 17
Rebasing tokens explained
A balance can change through a supply-adjustment mechanism rather than an ordinary transfer.
3 MIN READ - 18
Fee-on-transfer tokens explained
The requested amount and the recipient’s net increase can differ.
3 MIN READ - 19
Events versus actual token behavior
A log is a record emitted by code, not a universal guarantee of balance movement.
3 MIN READ - 20
Token interface practice set
Distinguish identity, amounts, permissions and event layouts.
3 MIN READ