Free Software Collection
Free API Testing and Database Clients
API clients moved to the cloud collectively a few years ago: collections sync to a vendor server by default, nothing works signed out, collaboration is billed per seat, and free tiers cap how many collections you may keep. Yet request definitions belong in Git next to the code, and environment variables frequently hold production secrets — neither belongs on someone else's server. Everything here keeps data local. The list sorts three ways — sending requests, inspecting requests, and connecting to databases.
12 curated recommendations
Selection Criteria
- Every core feature works without signing in.
- Collections and connection settings live locally, exportable and versionable.
- No pricing by seat, collection count or request volume.
- Request contents and database credentials are not uploaded to a vendor.
Recommended Tools
Bruno
An offline-first, Git-native open-source API client
- Open Source
- No Ads
- No Tracking
- Offline
Hoppscotch
An open-source API tool you use straight from the browser
- Open Source
- No Ads
- Cross-platform
- Self-hostable
mitmproxy
See exactly what requests an app or page is really making
- Open Source
- No Ads
- No Tracking
- Offline
DBeaver Community
One open-source SQL client for every database
- Open Source
- No Ads
- No Sign-up
- Offline
Beekeeper Studio
A SQL client that connects and queries immediately — no JDBC setup
- Open Source
- No Ads
- No Tracking
- No Sign-up
DB Browser for SQLite
Open a SQLite file and edit it like a spreadsheet
- Open Source
- No Ads
- No Tracking
- Offline
Recommended Skills & MCP
MCP Toolbox for Databases
Google's open-source MCP server for many databases
Works with: Claude Code · Cursor · Gemini CLI
- Open Source
- No Ads
- No Sign-up
DuckDB MCP
Let AI analyze local CSV and Parquet with DuckDB
Works with: Claude · Claude Code · Cursor
- Open Source
- No Ads
- No Tracking
ClickHouse MCP
ClickHouse's official MCP for AI-driven analytics
Works with: Claude · Claude Code · Cursor
- Open Source
- No Ads
- No Tracking
Qdrant MCP
Qdrant's official MCP — a semantic memory for AI
Works with: Claude · Claude Code · Cursor
- Open Source
- No Ads
- No Tracking
Neo4j MCP
Query Neo4j in plain language or use it as graph memory
Works with: Claude · Claude Code · Cursor
- Open Source
- No Ads
- No Tracking
MCP Inspector
The official visual debugger for MCP servers
Works with: Any MCP server
- Open Source
- No Ads
- No Tracking
FAQ
- What replaces Postman?
- Bruno. It stores collections as plain text files that go straight into the Git repository beside the code, so changes show up in a diff and merge conflicts resolve normally. No sign-in and no cloud sync layer. If you want something instantly usable in a browser, Hoppscotch does that and can also be self-hosted.
- How do I see what an app is actually sending?
- mitmproxy. It is a man-in-the-middle proxy — point a device's traffic at it and every HTTPS request is visible, editable and replayable. It is how you debug your own mobile app or find out what a third-party SDK reports. It requires installing a trusted certificate on the device, and recent Android versions add restrictions there for ordinary apps, which is worth knowing in advance.
- DBeaver or Beekeeper for databases?
- DBeaver is the most complete, connecting to nearly everything and handling ER diagrams, data migration and stored procedure debugging, at the cost of a slow Java start, a dense interface and a driver download on first connection. Beekeeper Studio's community edition opens fast and stays clean, which suits everyday lookups, small edits and CSV exports. For SQLite files alone, DB Browser for SQLite is the most direct — edit data like a spreadsheet.
- What is limited in the free Beekeeper Studio?
- The community edition is GPL-3.0 and covers everyday querying and editing. The commercial edition adds more database types, shared team queries and encrypted connection management. The download page offers the commercial trial by default, and the open-source build is under Community Edition — easy to miss.