Show HN: SQL-tap – Real-time SQL traffic viewer for PostgreSQL and MySQL

Hacker News · Feb 14, 2026 · Collected from RSS

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sql-tap Real-time SQL traffic viewer — proxy daemon + TUI client. sql-tap sits between your application and your database (PostgreSQL or MySQL), capturing every query and displaying it in an interactive terminal UI. Inspect queries, view transactions, and run EXPLAIN — all without changing your application code. Installation Homebrew brew install --cask mickamy/tap/sql-tap Go go install github.com/mickamy/sql-tap@latest go install github.com/mickamy/sql-tap/cmd/sql-tapd@latest Build from source git clone https://github.com/mickamy/sql-tap.git cd sql-tap make install Docker PostgreSQL FROM postgres:18-alpine ARG SQL_TAP_VERSION=0.0.1 ARG TARGETARCH ADD https://github.com/mickamy/sql-tap/releases/download/v${SQL_TAP_VERSION}/sql-tap_${SQL_TAP_VERSION}_linux_${TARGETARCH}.tar.gz /tmp/sql-tap.tar.gz RUN tar -xzf /tmp/sql-tap.tar.gz -C /usr/local/bin sql-tapd && rm /tmp/sql-tap.tar.gz ENTRYPOINT ["sql-tapd", "--driver=postgres", "--listen=:5433", "--upstream=localhost:5432", "--grpc=:9091"] MySQL FROM mysql:8 ARG SQL_TAP_VERSION=0.0.1 ARG TARGETARCH ADD https://github.com/mickamy/sql-tap/releases/download/v${SQL_TAP_VERSION}/sql-tap_${SQL_TAP_VERSION}_linux_${TARGETARCH}.tar.gz /tmp/sql-tap.tar.gz RUN tar -xzf /tmp/sql-tap.tar.gz -C /usr/local/bin sql-tapd && rm /tmp/sql-tap.tar.gz ENTRYPOINT ["sql-tapd", "--driver=mysql", "--listen=:3307", "--upstream=localhost:3306", "--grpc=:9091"] Quick start 1. Start the proxy daemon # PostgreSQL: proxy listens on :5433, forwards to PostgreSQL on :5432 DATABASE_URL="postgres://user:pass@localhost:5432/db?sslmode=disable" \ sql-tapd --driver=postgres --listen=:5433 --upstream=localhost:5432 # MySQL: proxy listens on :3307, forwards to MySQL on :3306 DATABASE_URL="user:pass@tcp(localhost:3306)/db" \ sql-tapd --driver=mysql --listen=:3307 --upstream=localhost:3306 2. Point your application at the proxy Connect your app to the proxy port instead of the database port. No code changes needed — sql-tapd speaks the native wire protocol. 3. Launch the TUI sql-tap localhost:9091 All queries flowing through the proxy appear in real-time. Usage sql-tapd sql-tapd — SQL proxy daemon for sql-tap Usage: sql-tapd [flags] Flags: -driver database driver: postgres, mysql (required) -listen client listen address (required) -upstream upstream database address (required) -grpc gRPC server address for TUI (default: ":9091") -dsn-env env var holding DSN for EXPLAIN (default: "DATABASE_URL") -version show version and exit Set DATABASE_URL (or the env var specified by -dsn-env) to enable EXPLAIN support. Without it, the proxy still captures queries but EXPLAIN is disabled. sql-tap sql-tap — Watch SQL traffic in real-time Usage: sql-tap [flags] <addr> Flags: -version Show version and exit <addr> is the gRPC address of sql-tapd (e.g. localhost:9091). Keybindings List view Key Action j / ↓ Move down k / ↑ Move up Ctrl+d / PgDn Half-page down Ctrl+u / PgUp Half-page up / Incremental search s Toggle sort (chronological/duration) Enter Inspect query / transaction Space Toggle transaction expand / collapse Esc Clear search filter x EXPLAIN X EXPLAIN ANALYZE e Edit query, then EXPLAIN E Edit query, then EXPLAIN ANALYZE a Analytics view c Copy query C Copy query with bound args q Quit Inspector view Key Action j / ↓ Scroll down k / ↑ Scroll up x EXPLAIN X EXPLAIN ANALYZE e / E Edit and EXPLAIN / ANALYZE c Copy query C Copy query with bound args q Back to list Analytics view Key Action j / ↓ Move down k / ↑ Move up Ctrl+d Half-page down Ctrl+u Half-page up h / ← Scroll left l / → Scroll right s Cycle sort (total/count/avg) c Copy query q Back to list Explain view Key Action j / ↓ Scroll down k / ↑ Scroll up h / ← Scroll left l / → Scroll right c Copy explain plan e / E Edit and re-explain / re-analyze q Back to list How it works ┌─────────────┐ ┌───────────────────────┐ ┌────────────────────┐ │ Application │─────▶│ sql-tapd (proxy) │─────▶│ PostgreSQL / MySQL │ └─────────────┘ │ │ └────────────────────┘ │ captures queries │ │ via wire protocol │ └───────────┬───────────┘ │ gRPC stream ┌───────────▼───────────┐ │ sql-tap (TUI) │ └───────────────────────┘ sql-tapd parses the database wire protocol (PostgreSQL or MySQL) to intercept queries transparently. It tracks prepared statements, parameter bindings, transactions, execution time, rows affected, and errors. Events are streamed to connected TUI clients via gRPC. License MIT