Compared honestly · updated 2026-09-26
Fiddler went subscription, then non-commercial. CallFlow is a $20 debugger that lives in your editor.
Fiddler Classic was the free HTTP debugger for a generation of Windows developers. Since 3 August 2026 its licence forbids commercial use, with a deadline of 17 September 2026 to move to Fiddler Everywhere, which has been subscription-only with a mandatory Telerik account since 2021. CallFlow Pro is the part of that job most developers actually need, capturing what their own code sends, done inside VS Code for a one-time $20.
- Fiddler Everywhere: Lite $7, Pro $13, Enterprise $37 per user per month billed annually; Telerik account required; offline mode is Enterprise-only.
- Fiddler Classic: free but non-commercial since 3 August 2026, Windows only, and "not in active development" in Telerik's words.
- CallFlow: capture, inspect and replay from VS Code terminals and debug sessions through a local proxy, $20 once, no account. It does not try to be a system-wide proxy.
Fiddler Everywhere vs CallFlow, side by side
| Fiddler Everywhere | CallFlow | |
|---|---|---|
| Price | Lite $7/mo, Pro $13/mo, Enterprise $37/mo (annual billing); 10-day trial, no free plan | Free REST client; Pro $20 one-time |
| Account required | Yes, Telerik account | No |
| Offline use | Enterprise tier only | Always; the licence check is offline |
| Where it runs | Standalone Electron app; system-wide proxy | Inside VS Code; proxy on 127.0.0.1 scoped to the workspace's terminals and debug sessions |
| Traffic scope | Everything on the machine (or per-app rules) | Programs started from VS Code, plus a browser you launch through it |
| HTTPS interception | Yes, with Fiddler's root CA installed system-wide | Yes, with a CA generated on your machine; system trust only needed for browsers and GUI apps |
| Compose and replay | Yes | Yes; captured calls become saved .http requests |
| Rules / rewriting / breakpoints | Yes | Not in 0.1 |
| Protocols | HTTP/1.1, HTTP/2, WebSocket, gRPC | HTTP/1.1, HTTPS; HTTP/2 in fallback mode; no HTTP/3 |
| Platforms | Windows, macOS, Linux | Wherever VS Code runs |
| Fiddler Classic (for reference) | Free, Windows only, non-commercial since 3 Aug 2026, "not in active development" | — |
Competitor facts were checked on 2026-09-26 against the sources linked below. If something has changed, tell us and we will correct it.
Where Fiddler Everywhere users get hurt
"Free forever" ended on 3 August 2026
Fiddler Classic's new licence agreement is "intended exclusively for Non-Commercial Users", with a transition page telling commercial users to move to Fiddler Everywhere or stop by 17 September 2026. Telerik's FAQ says Classic "is not deprecated, but it is not in active development and offers no commitments for releases, patches or tech support." Eric Lawrence, who created Fiddler, wrote that Telerik "had loudly promised that Fiddler would remain 'free forever'" and that "you cannot use Fiddler Classic for commercial purposes, even if you pay!"
Sources: Fiddler Classic licence agreement · Commercial-use transition page · Eric Lawrence, Fiddler in 2026
Subscription plus account, and offline only at the top tier
Fiddler Everywhere dropped its free plan in version 2.0 (June 2021): "Move to premium subscription only with free trial." Prices rose in January 2024. Today the plans are $7, $13 and $37 per user per month on annual billing, a Telerik account is required, subscriptions auto-renew, and the documentation says offline mode "requires a licensed seat under the Fiddler Everywhere Enterprise subscription tier."
Sources: Fiddler Everywhere 2.0 release notes · Price changes, Dec 2023 · Current pricing · Offline mode documentation
What people say they will pay for
The one-time alternatives are healthy: Charles is $50 per major version and a 2025 Hacker News thread about it summarised the mood as "Worth the money. And no subscription"; Proxyman is $89 perpetual. On HTTP Toolkit's launch thread the top complaint was the model itself: "Would expect this to be a one time payment rather than a monthly fee for this type of software."
Sources: Charles licences · Hacker News on Charles, Dec 2025 · Hacker News on HTTP Toolkit, Dec 2021
What CallFlow does instead
CallFlow Pro starts a proxy on 127.0.0.1 and tells VS Code to route every new terminal and debug session in the workspace through it, using the same environment variables Node, Python, curl, Go, .NET and Java already honour. HTTPS is decrypted with a CA generated on your machine; terminals trust it through those variables without touching the system store, and for browsers CallFlow shows the exact trust command and runs it only when you press the button. Captured calls appear in an inspector with headers, bodies, timings and TLS details; any of them can become a saved .http request, be edited, and replayed.
It costs $20 once, needs no account, makes no network requests of its own, and the free REST client underneath it is yours to keep either way.
To be fair to Fiddler Everywhere
Fiddler Everywhere is a full system-wide debugging proxy: rules engine, breakpoints, request composer, HTTP/2 and gRPC, mobile device capture, team sharing. If you need to intercept a desktop app you did not start from VS Code, or rewrite traffic on the fly, CallFlow 0.1 does not do that and Fiddler, Charles, Proxyman or mitmproxy will. CallFlow is scoped to the code you are working on, which is the point, and the limit.
Try CallFlow
Free on the Visual Studio Marketplace (Open VSX coming soon). No account, no server, no telemetry. CallFlow Pro is a $20 one-time purchase, sold through Paddle, and your files and exports are never paywalled.
Install from the Visual Studio Marketplace Read how CallFlow works
Questions people ask
- Does CallFlow capture traffic from apps outside VS Code?
- Only if you start them from a VS Code terminal or debug session, or launch a browser through CallFlow. It is not a system-wide proxy, by design.
- Do I have to install a certificate?
- For terminal programs, no: CallFlow points them at its CA file through environment variables. For browsers and GUI apps, yes, and CallFlow shows the exact command before running it.
- What cannot be captured?
- Programs that ignore proxy environment variables, apps with certificate pinning (recorded as pass-through metadata), HTTP/3, and Java without the standard proxy flags.
- Is there a subscription?
- No. Pro is $20 once through Paddle. There is nothing to cancel.