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A method of representing fractional numbers using integers with an implicit decimal point at a fixed position, avoiding floating-point imprecision. On Solana, all token amounts use fixed-point: SPL tokens have a configurable decimals field (e.g., USDC uses 6 decimals, so 1 USDC = 1,000,000 smallest units). DeFi protocols use basis points (1/10,000), scaled integers, or WAD/RAY notation (10^18/10^27) for precise rate calculations without floating-point types.

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Fixed-Point Arithmetic (fixed-point-arithmetic)
Category: Programming Fundamentals
Definition: A method of representing fractional numbers using integers with an implicit decimal point at a fixed position, avoiding floating-point imprecision. On Solana, all token amounts use fixed-point: SPL tokens have a configurable decimals field (e.g., USDC uses 6 decimals, so 1 USDC = 1,000,000 smallest units). DeFi protocols use basis points (1/10,000), scaled integers, or WAD/RAY notation (10^18/10^27) for precise rate calculations without floating-point types.
Related: Precision Loss / Rounding Errors, Checked Math, SPL Token Program

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Precision Loss / Rounding Errors

A class of numerical vulnerability where integer division discards fractional remainders, causing systematic under-accounting of fees, interest, or token amounts that an attacker can exploit through repeated small transactions to drain protocol funds or receive more than entitled. Because Solana programs use integer arithmetic exclusively (no native floating point in on-chain code), division operations like amount / price always truncate toward zero, and protocols must decide whether to round in favor of the protocol (ceiling division for fees collected, floor division for tokens distributed) using formulas such as (numerator + denominator - 1) / denominator. Precision errors can also compound across fixed-point representations, so high-precision intermediate scaling (e.g., multiplying by 10^9 before dividing) is a common mitigation.

Integer Overflow / Underflow

Open term

Branch

Checked Math

A family of Rust arithmetic methods — including checked_add, checked_sub, checked_mul, checked_div, and their saturating_* counterparts — that return an Option<T> (None on overflow/underflow) instead of silently wrapping, allowing Solana programs to propagate an error rather than continue with corrupted values. Because Rust's default integer arithmetic panics on overflow only in debug builds and wraps silently in release builds (the mode used for on-chain deployments), all financial and security-sensitive arithmetic in Solana programs should use these methods. Anchor's declare_program! macro and many audit checklists explicitly require checked math on all token amount calculations.

Open term

Branch

SPL Token Program

The original Solana Program Library token program (TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA) that implements fungible and non-fungible token operations. It manages mints (token definitions) and token accounts (balances). Core instructions include InitializeMint, MintTo, Transfer, Burn, Approve (delegation), and Revoke. All SPL tokens on mainnet before Token-2022 use this program.

Mint Token Account

Open term

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Security

Precision Loss / Rounding Errors

A class of numerical vulnerability where integer division discards fractional remainders, causing systematic under-accounting of fees, interest, or token amounts that an attacker can exploit through repeated small transactions to drain protocol funds or receive more than entitled. Because Solana programs use integer arithmetic exclusively (no native floating point in on-chain code), division operations like amount / price always truncate toward zero, and protocols must decide whether to round in favor of the protocol (ceiling division for fees collected, floor division for tokens distributed) using formulas such as (numerator + denominator - 1) / denominator. Precision errors can also compound across fixed-point representations, so high-precision intermediate scaling (e.g., multiplying by 10^9 before dividing) is a common mitigation.

Open term

Security

Checked Math

A family of Rust arithmetic methods — including checked_add, checked_sub, checked_mul, checked_div, and their saturating_* counterparts — that return an Option<T> (None on overflow/underflow) instead of silently wrapping, allowing Solana programs to propagate an error rather than continue with corrupted values. Because Rust's default integer arithmetic panics on overflow only in debug builds and wraps silently in release builds (the mode used for on-chain deployments), all financial and security-sensitive arithmetic in Solana programs should use these methods. Anchor's declare_program! macro and many audit checklists explicitly require checked math on all token amount calculations.

Open term

Token Ecosystem

SPL Token Program

The original Solana Program Library token program (TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA) that implements fungible and non-fungible token operations. It manages mints (token definitions) and token accounts (balances). Core instructions include InitializeMint, MintTo, Transfer, Burn, Approve (delegation), and Revoke. All SPL tokens on mainnet before Token-2022 use this program.

Open term

Programming Fundamentals

Git

A distributed version control system for tracking code changes across development teams. Essential for Solana development workflows: feature branches for program changes, pull requests for code review, tags for release versions. Solana Verify uses git repos to verify on-chain programs match public source. GitHub hosts most Solana ecosystem repositories.

Open term

Related terms

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Securityprecision-loss

Precision Loss / Rounding Errors

A class of numerical vulnerability where integer division discards fractional remainders, causing systematic under-accounting of fees, interest, or token amounts that an attacker can exploit through repeated small transactions to drain protocol funds or receive more than entitled. Because Solana programs use integer arithmetic exclusively (no native floating point in on-chain code), division operations like amount / price always truncate toward zero, and protocols must decide whether to round in favor of the protocol (ceiling division for fees collected, floor division for tokens distributed) using formulas such as (numerator + denominator - 1) / denominator. Precision errors can also compound across fixed-point representations, so high-precision intermediate scaling (e.g., multiplying by 10^9 before dividing) is a common mitigation.

Open term

Securitychecked-math

Checked Math

A family of Rust arithmetic methods — including checked_add, checked_sub, checked_mul, checked_div, and their saturating_* counterparts — that return an Option<T> (None on overflow/underflow) instead of silently wrapping, allowing Solana programs to propagate an error rather than continue with corrupted values. Because Rust's default integer arithmetic panics on overflow only in debug builds and wraps silently in release builds (the mode used for on-chain deployments), all financial and security-sensitive arithmetic in Solana programs should use these methods. Anchor's declare_program! macro and many audit checklists explicitly require checked math on all token amount calculations.

Open term

Token Ecosystemspl-token

SPL Token Program

The original Solana Program Library token program (TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA) that implements fungible and non-fungible token operations. It manages mints (token definitions) and token accounts (balances). Core instructions include InitializeMint, MintTo, Transfer, Burn, Approve (delegation), and Revoke. All SPL tokens on mainnet before Token-2022 use this program.

Open term

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Programming Fundamentals

Rust

A systems programming language emphasizing memory safety, zero-cost abstractions, and concurrency without a garbage collector. Rust uses an ownership model with borrow checking at compile time to prevent data races and null pointer bugs. It is the primary language for Solana program development (via Anchor or native solana-program crate) and the Agave validator client.

Open term

Programming Fundamentals

TypeScript

A statically typed superset of JavaScript that compiles to plain JavaScript. TypeScript adds type annotations, interfaces, generics, and enums to catch errors at compile time. It is the standard language for Solana client-side development—wallet adapters, dApp frontends, test suites, and SDK interactions (web3.js, Anchor client) are typically written in TypeScript.

Open term

Programming Fundamentals

JavaScript

The ubiquitous scripting language for web development, running in browsers and Node.js. JavaScript is dynamically typed and event-driven. Most Solana dApp frontends and scripts use JavaScript/TypeScript with libraries like @solana/web3.js. Node.js enables server-side JS for backend services, indexers, and bot development.

Open term

Programming Fundamentals

Node.js

A JavaScript runtime built on Chrome's V8 engine that enables server-side JavaScript execution. Node.js uses an event-driven, non-blocking I/O model. In the Solana ecosystem, Node.js is used for: running Anchor tests (Mocha/Jest), backend services, transaction bots, indexers, and CLI tools. npm/yarn/pnpm manage JavaScript package dependencies.

Open term