A modern, lightweight, multi-engine database client — an open-source alternative in the spirit of Navicat.

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Squaero (Latin quaero, "I seek / I inquire") is a multi-engine database client with a C core (libdbcore) and a web UI running on the OS-native webview (WebView2 on Windows, WebKitGTK on Linux, WKWebView on macOS). A modern UI without the weight of Electron, and a native engine that talks directly to each database's client libraries.

Supported engines

Engine	Status
SQLite	✅ Complete (verified)
PostgreSQL	✅ Via libpq — SSL/TLS, SCRAM
MySQL / MariaDB	✅ Complete (verified) — SSL/TLS, SSH tunnel
Informix	✅ Over DRDA, no IBM client needed
MongoDB	✅ mongosh syntax — find/aggregate, writes (insert/update/replace/delete), indexes, runCommand; edit documents in the grid by _id; a collection's definition as a script; execution plan (.explain()), operations monitor (currentOp/killOp), profiler-backed slow queries, collection/view/index management from the tree, cancel (killOp), and transactions on a replica set or sharded cluster (a standalone server says so)
SQL Server	✅ Via FreeTDS — queries, types, schema, transactions, encryption, named instances, cancel. Not yet: editing rows in the grid, DDL
Oracle	⏳ Planned (M12)

Engines load as plugins (.dll/.so) implementing a C contract: adding an engine never touches the core. See how to write a driver.

Features

SQL editor

• CodeMirror editor that understands the query: contextual completion (aliases, CTEs, subqueries, joins along foreign keys, clause keywords), diagnostics (unknown names, ambiguous columns, risky writes), go to definition, find usages and rename within the script, multicursor and abbreviation templates.
• SQL formatting per engine dialect; run selection / statement / document.
• Query history with per-query duration and slow-query marks, and a local history of each tab's text, so overwritten or closed work can be restored.
• Snippets / favorites; command palette (Ctrl/Cmd+K).
• Visual execution plan (EXPLAIN) as a tree.

Safe execution

• Per-connection safe mode: read-only (writes are refused before they are sent) or confirm writes.
• Manual transactions with commit/rollback, or auto-commit.
• Cancel a running query on every engine; what an engine cannot do is shown disabled with the reason, never faked.
• Lost-connection recovery (reconnects, and retries a read only when it is safe) and an optional keep-alive.

Result grid

• Virtualized, per-column sort and filter, real pagination (offset).
• Inline transactional editing (insert/update/delete + SQL preview + commit/rollback); row detail (form view).
• Cell-range selection with a summary in the status bar (count, NULLs, sum, average, min, max), and a transposed view of wide results.
• Pin a result so the next run does not replace it, and compare two results.
• Export CSV / JSON / SQL / XML / HTML / XLSX; import CSV / JSON / XLSX.
• Charts (bar / line / pie).

Objects and design

• Lazy, virtualized object tree grouped by type (tables, views, procedures, functions, triggers, events), served from a schema cache while it is re-read in the background.
• Table designer (create and ALTER), index and constraint editor.
• Procedures / functions, triggers / events, users and privileges.
• Server monitor (process list + kill), slow queries.
• ER diagram (real foreign keys from the engine) and a visual query builder.
• Search a text across the tables of a schema.

Data across connections

• Schema diff with a reviewable, dependency-ordered migration script; data sync, table transfer between connections, and test data generation.
• Backup and restore, and the schema DDL to a folder, one .sql file per object, ready to version in git.

Connectivity and platform

• SSH tunnel (all engines), SSL/TLS (MySQL, PostgreSQL, MongoDB, Informix, SQL Server), and import/export of saved connections — including DBeaver's data-sources.json (with the credentials-config.json beside it) and Navicat's .ncx, passwords and all, so moving in does not start with retyping thirty servers.
• Four built-in styles — B · Nativo (the default), A · Quiet pro, C · Editorial and Rosa pastel, each light and dark — plus the earlier themes and your own, imported as a file. Configurable typography, interface zoom and grid style.
• Desktop behaviour: a native menu bar on Windows and Linux, the app's own icon set, remembered window state, editable keyboard shortcuts (list), adaptive context menus.
• Single executable (embedded UI) + drivers as plugins. No Electron.

Beyond the desktop

• quaero-mcp: a Model Context Protocol server that exposes the connections you opt in to MCP clients, read-only unless you allow writes.
• iPhone: the same core and drivers with a SwiftUI app — browse, query, edit with Face ID and a transaction, export — and, on devices with Apple's on-device model, filter a table by asking. Being prepared for the App Store.

Install

Windows: download the latest .msi installer from Releases and run it. Requires the WebView2 runtime (already bundled in Windows 11). Every release attaches a SHA256SUMS.txt to verify the download: sha256sum -c SHA256SUMS.txt (or CertUtil -hashfile squaero-*.msi SHA256). Releases from v0.26.0 on also carry a signed build-provenance attestation, which proves the MSI was built by this repository's release workflow: gh attestation verify squaero-X.Y.Z-x64.msi --repo danielnuld/squaero. The MSI is not Authenticode-signed yet, so Windows SmartScreen shows an unknown publisher.

Informix needs no IBM client: Squaero speaks DRDA to the server with libdrda. The server must have a DRDA listener (an sqlhosts entry of protocol drsoctcp, usually port 9089; check with onstat -g ntt). Saved connections from earlier versions move to port 9089 on their own, and ask you to check the port when theirs was not 9088.

Linux: from v0.29.0, releases attach a .deb for Ubuntu 24.04+ and Debian 13+ (x86_64), listed in the same SHA256SUMS.txt: sudo apt install ./squaero_X.Y.Z_amd64.deb. apt pulls in every driver's client library. On any distribution with snapd, install it from the Snap Store: sudo snap install squaero.

macOS: from v0.32.0, releases attach squaero-X.Y.Z-arm64.dmg for Apple Silicon on macOS 15 or later: open it and drag Squaero to Applications. It is signed ad hoc, not with an Apple Developer ID, so the first launch is blocked once: open System Settings → Privacy & Security and choose Open Anyway (or run xattr -dr com.apple.quarantine /Applications/Squaero.app).

AppImage/Flatpak and an Intel Mac build are not planned yet.

Build from source

Requirements: CMake ≥ 3.20, a C11 compiler (GCC/Clang/MSVC) and, recommended, Ninja; Node + pnpm for the UI.

# UI (produces frontend/dist/index.html, a single file that gets embedded)
pnpm --dir frontend install
pnpm --dir frontend build

# Core + app
cmake -S . -B build -G Ninja
cmake --build build
ctest --test-dir build --output-on-failure   # core tests

The binary lands in build/app/squaero (.exe on Windows). Webview dependencies: Linux libgtk-4-dev libwebkitgtk-6.0-dev; macOS system WebKit; Windows WebView2 (downloaded at build time). Core only: -DQUAERO_BUILD_APP=OFF.

PostgreSQL: the driver links libpq: a system libpq when there is one; the Windows release build compiles a static libpq from source with -DQUAERO_LIBPQ=ON.

MongoDB: the driver links libmongoc. Without a system copy, build it from source with -DQUAERO_MONGOC=ON (fetches and statically links mongo-c-driver; TLS via Secure Channel on Windows).

SQL Server: the driver links FreeTDS's db-lib, 1.4 or newer. Without one (Ubuntu 24.04's is older), -DQUAERO_FREETDS=ON fetches FreeTDS and links it statically, as the release builds do.

Windows MSI installer: see installer/build-msi.sh (WiX v5 via dotnet tool). Releases are cut automatically on a version tag — see docs/VERSIONING.md.

Per-engine smoke: scripts/smoke/run.sh <sqlite|mysql|mongodb> — see docs/QA-SMOKE.md.

Architecture

Frontend (OS webview)  ──JSON IPC──>  C core (libdbcore)  ──vtable──>  Drivers (plugins)
   SolidJS UI, virtual grid,           connection, queries,             sqlite, postgres,
   SQL editor, tools                   introspection, editing, tx       mysql, informix, mongodb, mssql

Details in docs/ARCHITECTURE.md.

Documentation

Most documents under docs/ are in Spanish; the MCP server, the MongoDB result model, the UI glossary and the trademark policy are in English.

• ROADMAP · Architecture · IPC protocol
• Driver contract · How to write a driver · MongoDB result model
• Keyboard shortcuts · UI glossary · MCP server
• Verification matrix · Per-engine smoke · Versioning and releases
• M14 design direction · Brand · Website
• Contributing · Code of conduct · Third-party inventory · Trademark policy

License

GPLv3, with an additional permission to ship through app stores such as Apple's App Store. The name and logos are covered by the trademark policy: forks are welcome under their own name. Proprietary-engine drivers ship as separate plugins, loaded at runtime, to respect their licenses. Full third-party inventory in THIRD-PARTY.md.