FlosForge Caller for macOS, Windows and Linux
Free, private HTTP API client for macOS, Windows and Linux
Send requests, run collections and test APIs without creating an account or logging in. FlosForge Caller opens the collections and environments you already have, runs their pre-request and test scripts, and stores everything as readable JSON right on your computer. Free and open source under the GNU GPL v3.
- Opens your existing collections
- Runs pm.* scripts and tests
- Collection runner and CLI for CI
Sample data: every name, site, address, company and figure shown is invented. Any resemblance to a real person, business, product or website is coincidental and implies no affiliation, endorsement or relationship of any kind.
- Runs on
- macOS, Windows and Linux
- Opens
- Collection exports v1 to v2.1
- Keeps data
- Plain JSON on your computer
- Account
- None, ever
Bring the collections you already have
Export your collections, environments, or full workspace dumps from your current API client and drop the files straight into Caller. Folders, requests, payload types, auth configurations, variables, and scripts carry over cleanly, and a clear import summary flags anything that needs a manual check. You can also paste raw cURL commands directly into the URL bar to turn them into requests instantly.
- Collection exports (v1, v2.0, and v2.1), environments, globals, and full data dumps
- Paste cURL commands directly into the URL bar to create requests
- Export as v2.1 collections, cURL, or code snippets for fetch, Python, HTTPie, and Go
- Secret environment values stay safely masked during import
The scripts and tests you wrote still run
You do not have to rewrite your workflows. Pre-request and post-response scripts use the familiar pm.* API across collections, folders, and individual requests, so most existing scripts run without modification. Test results show pass and fail badges right beside the response, with console output organized into its own tab.
- pm.test and pm.expect with Chai, pm.environment, pm.variables, and pm.sendRequest
- CryptoJS, Lodash, and compatibility with the legacy global script API and tests[]
- Scripts execute in an isolated worker that cannot touch your local files
- Configurable execution timeouts stop hung or runaway scripts automatically
Run a whole collection, in the app or in CI
The collection runner executes entire collections or specific folders in sequence. You can loop runs, add custom delays, or iterate through rows of a CSV or JSON data file with variables flowing seamlessly from request to request. The exact same execution engine runs from your terminal using familiar command-line flags, making it easy to run automated suites in CI pipelines.
- Data-driven runs with CSV/JSON files, request delays, stop-on-failure, and setNextRequest flow control
- Export run results in Markdown, text, PDF, CSV, JSON, or JUnit XML with tokens and cookies masked
- Lightweight standalone CLI runner (~1 MB) that only requires Node.js
- Standard CI exit codes: 0 for all passed, 1 for failures, and 2 for syntax or usage errors
Everything stays on your computer
There is no account to create, no login prompt, and no cloud synchronization behind your back. Each workspace is a regular folder and each collection is stored as plain JSON, making your work transparent, easy to back up, and ready to version with Git. The only network traffic leaving your computer is the requests you choose to send.
- Independent workspaces with their own collections, environments, history, and accent colors
- Inspectable cookie jar that sends cookies automatically, just like a browser
- Connection timeline breaking down DNS, connect, TLS handshake, TTFB, and download duration
- Light and dark modes with 64 curated color themes, or create your own
Every feature, in full
A list of features you can find in the application.
Not supported yet
Most collections import cleanly out of the box. A few vendor-specific cloud features are not supported, and the import summary lists anything skipped during import:
- Saved request examples (mock response bodies)
- Digest, AWS Signature, Hawk, and NTLM authentication schemes
- Path-variable substitution tables (:id is dispatched as typed in the URL path)
- Visualizer scripts, scheduled cloud monitors, and hosted mock servers
Questions about FlosForge Caller
Can FlosForge Caller open my existing collections?
Yes. Export your collections (v1, v2.0, or v2.1), environments, globals, or a complete data dump from your current API client and drop the JSON files directly into Caller. Folders, requests, bodies, auth configurations, variables, and scripts carry over cleanly, with an import summary highlighting any unsupported properties.
Do I need to create an account or sign in?
No, never. There is no account registration, no sign-in requirement, and no cloud synchronization. All your collections, environments, and history are saved as plain JSON files directly on your computer.
Can I run collections automatically in CI pipelines?
Yes. The flosforge-caller command-line runner uses the exact same execution engine as the desktop application. It accepts familiar run flags, outputs standard JUnit XML or Markdown reports, and requires only Node.js 22 or later.
How every FlosForge app works
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No telemetry
No analytics, no crash reporting, no usage pings. Not configurable — simply absent.
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Local storage only
Your data stays on your own device, stored in private application sandboxes under your control.
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Open exports
Everything exports to standard formats you own (CSV, GPX, JSON, Markdown), with zero lock-in.
Getting it running
Download a prebuilt release from the GitHub Releases page, or clone the repository and build it yourself. Both give you the exact same app; building from source lets you inspect every line of code first.
Before you start
Because these builds are produced independently without expensive corporate code-signing certificates from Apple or Microsoft, macOS Gatekeeper and Windows SmartScreen will show an unverified developer warning when opened for the first time. Download installers exclusively from the project’s official GitHub Releases page, or build from source if you prefer full control over the binary.
What you need first
- macOS 13 Ventura or later, Windows, or Linux, on x64 or ARM64
- To build from source: Node.js 22 or later, and Git
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Download a build
Choose the installer for your platform from the Releases page: a .dmg for macOS (Apple silicon or Intel), an installer or portable .exe for Windows, or an AppImage, .deb, or .rpm for Linux.
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Open it the first time
On macOS, open the app, then click Open Anyway in System Settings → Privacy & Security. On Windows, click More info, then Run anyway on the SmartScreen dialog. On Linux, make the AppImage executable or install the .deb or .rpm with your package manager.
chmod +x FlosForge-Caller-*.AppImage -
Or build it from source
Clone the repository and install dependencies with npm.
git clone https://github.com/dimitriostzr/flosforge-http-caller.git cd flosforge-http-caller && npm install -
Run it, or package it
Start the app directly in development mode, or package a standalone installer for your operating system.
npm run dev npm run dist:mac # or dist:win, dist:linux
Free software · GPL-3.0-or-later · not sold
Free and open source
FlosForge Caller is released under the GNU General Public License v3. It is not sold — there is no paid version, no licence key and no tier — and the licence is the whole arrangement. In plain terms:
- Free to use for personal, academic, and commercial work alike, with no fees, subscriptions, or paywalled features.
- You are free to inspect every line of source code, customize the application, and compile your own builds.
- Any modified versions or redistributions must be shared under the same GNU GPL v3 licence with full source code made available.
- The GPL covers the source code; the FlosForge name and project icons remain reserved branding, so distributed forks should use their own branding.
- Provided "as is", without warranty of any kind. You are responsible for the network requests you send and the external services you connect to.
Read the GPL-3.0-or-later licence text The LICENSE file in the repository
Free, and the source is public
FlosForge Caller for macOS, Windows and Linux is free software, published in full on GitHub. Download it, audit it, or fork it. It is offered without a support commitment, so read the README first and try it on a machine you can afford to experiment with.