slack-volt

A Bolt-style framework for building Slack apps in Rust. Provides declarative handler registration, middleware, Block Kit builders, and first-class AWS Lambda support.

Built on top of slack-morphism for Slack API types.

Quick Start

use slack_volt::{AckResponse, App, CommandContext};
use slack_volt_lambda::LambdaAdapter;

async fn handle_hello(mut ctx: CommandContext) -> Result<AckResponse, slack_volt::Error> {
    Ok(ctx.ack(format!("Hello, <@{}>!", ctx.command.user_id)))
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
    let app = App::new()
        .bot_token(std::env::var("SLACK_BOT_TOKEN")?)
        .signing_secret(std::env::var("SLACK_SIGNING_SECRET")?)
        .command("/hello", handle_hello)
        .build();

    LambdaAdapter::run(app).await?;
    Ok(())
}

Features

• Slash commands — app.command("/name", handler)
• Events — app.event("app_mention", handler)
• Actions — app.action("button_click", handler)
• Modal submissions — app.view_submission("callback_id", handler)
• Block Kit DSL — blocks::section(), blocks::modal(), blocks::button(), etc.
• Signature verification — HMAC-SHA256 middleware, enabled automatically when signing secret is set
• AWS Lambda — slack-volt-lambda crate wraps your app as a Lambda handler via API Gateway

Crates

Installation

Add to your Cargo.toml:

[dependencies]
slack-volt = { git = "https://github.com/rajbot/slack-volt-rs" }
slack-volt-lambda = { git = "https://github.com/rajbot/slack-volt-rs" }
tokio = { version = "1", features = ["full"] }

Local Development

# Install cargo-lambda
brew install cargo-lambda

# Run locally (simulates API Gateway)
cargo lambda watch

# Test with curl
curl -X POST http://localhost:9000/lambda-url/hello_command \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "command=%2Fhello&text=world&user_id=U1&channel_id=C1&team_id=T1&trigger_id=tr1&user_name=test&channel_name=dev&response_url=http://example.com"

License

Apache-2.0