Anchor's event system using the `emit!()` macro. Events are defined with `#[event]` on structs and emitted as base64-encoded data in program logs (prefixed with a discriminator). Clients subscribe via `program.addEventListener('EventName', callback)`. Events cost compute units for logging and are limited by the 10KB log size.
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Anchor's event system using the `emit!()` macro. Events are defined with `#[event]` on structs and emitted as base64-encoded data in program logs (prefixed with a discriminator). Clients subscribe via `program.addEventListener('EventName', callback)`. Events cost compute units for logging and are limited by the 10KB log size.
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Anchor, local validators, explorers, SDKs, and testing workflows.
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Anchor Events (emit!) (anchor-events)
Category: Developer Tools
Definition: Anchor's event system using the `emit!()` macro. Events are defined with `#[event]` on structs and emitted as base64-encoded data in program logs (prefixed with a discriminator). Clients subscribe via `program.addEventListener('EventName', callback)`. Events cost compute units for logging and are limited by the 10KB log size.
Related: Anchor Framework, Program Log (msg! / sol_log)Use glossary context, relationships, mental models, and builder paths to get structured answers instead of generic chat output.
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The most popular framework for building Solana programs in Rust. Anchor provides macros (#[program], #[account], #[derive(Accounts)]) that auto-generate boilerplate for account validation, serialization, discriminators, and error handling. It includes a CLI (anchor init/build/test/deploy), IDL generation, and TypeScript client generation. Reduces program code by ~80% compared to native development.
Diagnostic output from programs using `msg!()` (Anchor) or `sol_log()` (native). Logs appear in transaction metadata and explorer UIs. Each log call costs compute units (~100 CU base + data length). Logs are limited to 10KB per transaction. Anchor events also emit as base64-encoded log messages.
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Anchor CLI commands for project lifecycle. `anchor init <name>` scaffolds a new project (program, tests, Anchor.toml). `anchor build` compiles to SBF and generates the IDL. `anchor test` builds, starts a local validator, deploys, and runs Mocha/Jest tests. `anchor deploy` deploys to the configured cluster. `anchor verify` checks deployed bytecode.
The most popular framework for building Solana programs in Rust. Anchor provides macros (#[program], #[account], #[derive(Accounts)]) that auto-generate boilerplate for account validation, serialization, discriminators, and error handling. It includes a CLI (anchor init/build/test/deploy), IDL generation, and TypeScript client generation. Reduces program code by ~80% compared to native development.
A major release (March 2025) of the Anchor framework introducing custom discriminators (overriding the default 8-byte discriminator to save transaction space), LazyAccount for on-demand deserialization to reduce compute costs, and stack memory optimizations for init constraints. Positioned as a major milestone on the roadmap toward v1.0.
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The most popular framework for building Solana programs in Rust. Anchor provides macros (#[program], #[account], #[derive(Accounts)]) that auto-generate boilerplate for account validation, serialization, discriminators, and error handling. It includes a CLI (anchor init/build/test/deploy), IDL generation, and TypeScript client generation. Reduces program code by ~80% compared to native development.
Diagnostic output from programs using `msg!()` (Anchor) or `sol_log()` (native). Logs appear in transaction metadata and explorer UIs. Each log call costs compute units (~100 CU base + data length). Logs are limited to 10KB per transaction. Anchor events also emit as base64-encoded log messages.
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The most popular framework for building Solana programs in Rust. Anchor provides macros (#[program], #[account], #[derive(Accounts)]) that auto-generate boilerplate for account validation, serialization, discriminators, and error handling. It includes a CLI (anchor init/build/test/deploy), IDL generation, and TypeScript client generation. Reduces program code by ~80% compared to native development.
The Anchor macro applied to structs to define on-chain account data layouts. `#[account]` auto-derives Borsh serialization, adds an 8-byte discriminator prefix (SHA-256 of 'account:<Name>'), and implements space calculation. Optional attributes: `#[account(zero_copy)]` for zero-copy deserialization of large accounts.
The Anchor macro that defines the accounts struct for an instruction. Each field specifies an account with validation constraints. Account types include: `Account<'info, T>` (deserialized), `Signer<'info>` (must sign), `Program<'info, T>` (program reference), `SystemAccount<'info>`, and `UncheckedAccount<'info>` (no validation, use carefully).
Declarative validation rules on Anchor account fields. Key constraints: `#[account(mut)]` (writable), `#[account(init, payer=x, space=n)]` (create), `#[account(seeds=[...], bump)]` (PDA validation), `#[account(has_one=field)]` (field equality), `#[account(constraint = expr)]` (custom boolean), `#[account(close=target)]` (close and reclaim rent).