Query String Parser
Parse URL query strings into key-value pairs with URL decoding and parameter counting.
How it works
- 1Paste or type your text in the input field
- 2Click "Process" — processing happens in your browser
- 3Copy the result or download as a text file
What to do next
About Query String Parser
Query String Parser runs the developer utility job locally inside your browser. Parse URL query strings into key-value pairs with URL decoding and parameter counting. The work happens on your machine, the result is generated on your machine, and the page exposes the controls you need to drive it without burying them in menus.
Query String Parser runs on standard browser APIs — an open-source, well-audited engine that performs the developer utility natively in the browser. It accepts the formats listed in the upload area and produces output that opens in any standard developer viewer. Per-run input is capped at 0 MB.
Reach for Query String Parser when you need a predictable result on a single file. The page works on the first visit, the controls are visible without a menu, and the output is delivered the moment the engine finishes.
Because everything runs in the page, the tool scales the same way for one user or a million — there is no per-user backend cost. The page is static, the engine is the same JavaScript bundle for every visitor, and the work happens on the visitor's own device. That keeps the tool free and keeps it fast on the first interaction.
Constraints worth knowing about: inputs are capped at 0 MB to keep memory usage in a sensible range, one input is processed per run, and the tool must be loaded over HTTPS for the in-browser engine to work. These are properties of the architecture.
Even on its own, Query String Parser composes well with the rest of your toolkit. The output is a standard developer file that opens in any program that handles the format, so the result of one run can become the input to whatever step you use next.
Query String Parser is shaped around the recurring needs of two audiences: devops engineers crafting one-liners, who use it as a quick utility between bigger tools, and data analysts wrangling JSON, who use it as their primary way of getting the job done. Both groups get the same defaults and the same speed.
Once the engine finishes, the output is offered as an immediate download. There is no preview gate, no email-wall, and no "register to download" intermediary — the file is yours the moment it is ready.
The transformation in Query String Parser is deterministic — the same input plus the same options produces the same result every run. That predictability matters when the result has to match an upstream specification or be reproducible later.
Query String Parser is structured around the idea that a useful tool should be its own page. Open the page, do the work, close the tab — the page is the entire product. There is no onboarding flow because there is nothing to onboard into.
Pro tip: Query String Parser works just as well in a private/incognito window as in a normal one, which is occasionally useful when you want zero browser-history footprint of the job. Another tip: if the tool ever feels slow, it is almost always because the browser tab is competing for CPU with another tab — pausing or closing the heavy ones gives the engine room to work.
Query String Parser is built around the moment of need: a focused page you open when you have a specific task, complete the task, and close. The catalog contains many adjacent tools so the same model serves the surrounding parts of a typical developer utility workflow.
When something goes wrong, the cause is usually one of three things: a malformed input, a browser that is out of memory, or a corporate proxy that is interfering with the page's static assets. The first two are easy to diagnose; the third typically requires asking your IT team to allow standard browser APIs to load.
If Query String Parser solved your problem, sharing the page link with someone who has the same problem is the most useful thing you can do. The catalog grows mostly through word of mouth; visitors arriving through a recommendation tend to be the ones the tool serves best.
How it works
- 1Land on the Query String Parser page. The tool is ready to use the moment the page renders.
- 2Add your developer input by dropping it onto the page or browsing for it.
- 3Adjust the options to match what you need. Sensible defaults cover the most common case, so you can usually skip this step.
- 4Trigger processing. standard browser APIs reads your input, applies the transformation, and writes the result back into the page.
- 5Save the output when it is ready.
- 6Run additional jobs as needed. The same controls and defaults apply on every run.
Common use cases
- Inspect a regex against a test string before committing it using Query String Parser.
- Encode binary content for transport in a JSON body.
- Pretty-print a minified blob during incident triage.
- Inspect a payload during local development without writing a script.
- Validate a config blob before pushing to staging.
- Format a noisy log line into something a teammate can read.
- Generate a quick fixture without leaving the browser.
- Convert between data formats while wiring up an integration.
- Compare two API responses to spot a regression.
- Decode a token to confirm its claims during a debugging session.
FAQ
What is a query string?
The part of a URL after the ? symbol, containing key=value pairs separated by &. For example: ?page=1&sort=name.
Are encoded values decoded?
Yes — %20, +, and all percent-encoded characters are decoded to their original form.
Can I paste a full URL?
Yes — the tool extracts the query string portion from a full URL automatically.
What about duplicate keys?
Duplicate keys are shown as separate entries. Some frameworks treat them as arrays.
What if there is no = sign?
Keys without values are parsed with an empty string value.
Private?
Yes — parsing runs locally.
Does Query String Parser match what professional tools produce?
Query String Parser is built on standard browser APIs, which is the same class of engine used by professional developer utility pipelines. For deterministic operations, the output is byte-identical to what an equivalent CLI run would produce; for operations involving a codec or a model, the result is well within the range of what comparable tools generate. If you have a specific reference output you need to match, run a small test job first to confirm the configuration produces what you expect.
Are jobs run with Query String Parser stored anywhere?
Favtoo keeps no copy of your file because Favtoo never receives your file. Query String Parser runs entirely in your browser, the input is held only in your tab's memory, and closing the tab discards it. There is no opt-in cloud history, no "recent jobs" panel synced to an account, and no server-side retention to configure — the architecture simply has nowhere for your file to be stored.
Where does my file actually go when I use Query String Parser?
Your file is processed inside your browser by standard browser APIs. The engine reads the file's bytes from your tab's memory, computes the result, and writes the result back into the tab. You can confirm what the page does by opening developer tools and watching the Network tab during a run — the requests you see are for the tool's static assets only.
Does Query String Parser work in Safari, Firefox, Chrome and Edge?
Query String Parser works in any modern browser released in the last few years — Chrome, Edge, Firefox, Safari, Brave, Arc and the major Chromium derivatives are all supported. The underlying engine relies on widely-supported web APIs, so there is nothing exotic to install. If you are on a very old browser version and the tool fails to load, updating to the latest release of your preferred browser is the only fix needed.
Which file formats does Query String Parser accept?
The accepted formats are listed in the upload area on the tool itself. If your input is in a format that is not directly supported, convert it first using one of Favtoo's converter tools — every Favtoo converter outputs a file that is a clean input to the next tool in the chain.
Is the source for Query String Parser available?
Query String Parser is a static page running an open-source engine in your browser, so a typical corporate firewall does not get in the way as long as it allows JavaScript to load from Favtoo. For teams that need to host it themselves on an internal network, the underlying engine (standard browser APIs) is open-source and can be packaged into a private build with the same behaviour. Reach out via the Contact page if that is something you are exploring.
Can I use Query String Parser on iOS or Android?
Query String Parser runs in any modern mobile browser — Safari, Chrome, Firefox and the in-app browsers in most messaging apps all support the underlying APIs. Performance depends on the device: a recent phone handles typical inputs nearly as fast as a laptop, while older devices may take a few seconds longer near the 0 MB ceiling. The interface lays out cleanly on small screens, so you do not need to pinch-zoom to see the controls.