URL Canonicalizer — Normalize URLs
Normalize URLs by lowercasing hosts, sorting query params, removing default ports and trailing slashes.
How it works
- 1Paste or type your text in the input field
- 2Click "Canonicalize" — processing happens in your browser
- 3Copy the result or download as a text file
What to do next
About URL Canonicalizer
URL Canonicalizer runs the web and productivity utility job locally inside your browser. Normalize URLs by lowercasing hosts, sorting query params, removing default ports and trailing slashes. 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.
Anyone who works with web and productivity utility on a casual basis — creators experimenting with formats, researchers gathering quick references, site owners auditing pages — finds URL Canonicalizer a quick way to get the result. The page loads in under a second, the controls are visible from a single screen, and the result downloads or copies in one click.
URL Canonicalizer performs the transformation entirely inside the JavaScript runtime. Your file lives in the tab's memory while the engine works on it; the result lives in the tab's memory until the browser triggers the download. Both are released when the tab closes, the way every browser tab releases its memory.
Architecturally, URL Canonicalizer is a single-page client. The processing layer is standard browser APIs; the UI is a thin React shell on top. Inputs flow through the engine and the output is returned to the browser as a Blob you can save or copy. The 0 MB cap is the only hard limit and it exists to keep memory usage stable on every device.
Reach for URL Canonicalizer 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.
If your task needs more than one step, chain URL Canonicalizer with Canonical URL Generator, URL Validator, and Query String Remover. Each tool produces output that is a clean input to the next, so multi-step workflows are just a matter of opening the next tool in a new tab and continuing.
URL Canonicalizer returns the result as a download. If you are running multiple jobs, the output names will not collide as long as the input names differ. You can re-run with different settings as many times as you like; each run produces a fresh file with no caching trickery in between.
The only practical limit is the 0 MB per-file ceiling, which keeps the tool responsive across a wide range of devices. Run the tool ten times in a row, run it ten thousand times — it behaves the same way and produces the same quality of result.
Some notes on the design of URL Canonicalizer. The page is intentionally narrow: one input, the controls relevant to the task, and one output. Adding unrelated features would make the common case slower for the majority of users, so the surface is held to what people actually use.
Some context on why URL Canonicalizer exists in this form: modern File APIs, high-performance JavaScript engines, and well-maintained open-source libraries now make it possible to perform web and productivity utility work entirely in the browser. URL Canonicalizer is built on top of that capability, which is why a single page can host the full pipeline.
Pro tip: URL Canonicalizer 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.
For most failure modes, refreshing the page and re-running the job is enough — the engine has no persistent state to corrupt. If the same input fails twice in a row, the input itself is most likely the problem (a truncated file, an unexpected variant of the format, or a stream the engine does not recognise).
URL Canonicalizer produces deterministic output: the same input plus the same options always produces the same result. That predictability matters when the result has to match an upstream specification or be reproducible later.
Open the workspace above to start using URL Canonicalizer. The engine loads on the first interaction so the page itself stays light, and once the tool is warm it processes subsequent jobs quickly. The moment the page is interactive, the tool is ready to do real work on your file.
How it works
- 1Open the URL Canonicalizer workspace above. The interface is a single page, so there is nothing to navigate.
- 2Drop a web utility file onto the upload area, or click to pick one from your device.
- 3Tweak the controls if the defaults are not quite right for your input. The options are kept short and labelled in plain language.
- 4Hit the run button. standard browser APIs does the work in your browser tab.
- 5Save the output when it is ready.
- 6Re-run with different settings as often as you want. Each run produces a fresh output and the original file on disk is never modified.
Common use cases
- Sanity-check a webhook response while debugging using URL Canonicalizer.
- Audit a marketing page before launch.
- Compare two product variations side by side.
- Run a fast accessibility check before publishing.
- Run a one-off check during a meeting without context-switching.
- Pull a quick reference number for a status update.
- Validate a setting before circulating it to a team.
- Preview how a result looks before deploying it.
FAQ
What is canonicalization?
Converting URLs to a standard form so equivalent URLs (different casing, param order) become identical.
What is normalized?
Lowercase host, lowercase protocol, default port removal, sorted query params, trailing slash removal, hash removal.
Batch support?
Enter one URL per line to canonicalize multiple URLs.
Private?
Yes — runs locally.
Trailing slashes?
Trailing slashes are removed from paths (except the root /).
Default ports?
Port 80 (HTTP) and 443 (HTTPS) are stripped as they are the defaults.
Will URL Canonicalizer ask me to pay to download the result?
URL Canonicalizer is free to use. The processing runs in your browser, which keeps the per-user cost low enough that the tool can be offered openly. The download is the same file the engine produced — you can use it for as many runs as you need.
Do I need a specific browser to use URL Canonicalizer?
URL Canonicalizer 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.
How often is URL Canonicalizer updated?
URL Canonicalizer is updated whenever the underlying engine releases an improvement or a bug fix. Because the tool is delivered as a static page, every visit fetches the latest version automatically — there is no "version" to manage on your end. If a particular release ever changes default behaviour, the change is documented on Favtoo's changelog so you can confirm what shifted.
Why use URL Canonicalizer instead of a paid online tool?
Desktop apps usually have more advanced features but require installation, maintenance and (often) a licence. Paid online tools are convenient but route your file through their servers and gate downloads behind accounts. URL Canonicalizer sits in between: free, instant, and private, but intentionally narrow in scope. For one-off jobs and the common web and productivity utility operations, it is usually the lowest-friction choice; for highly specialised work, a dedicated app is still the right answer.
How long does URL Canonicalizer take to process a file?
Most jobs finish in seconds. Speed scales with input size and with how many CPU cycles your browser tab has available — the engine runs in your browser, so it shares resources with whatever else you have open. For inputs near the 0 MB ceiling, expect anywhere from a few seconds to roughly a minute on a typical laptop. Closing other heavy tabs noticeably speeds things up.
Does URL Canonicalizer upload my file to a server?
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.
Can I self-host URL Canonicalizer for my team?
URL Canonicalizer 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.
Is URL Canonicalizer lossless?
URL Canonicalizer is built to preserve quality wherever the underlying web utility format allows it. Operations that are mathematically lossless (e.g. structural transformations, lossless re-encoding) round-trip with no perceptible change. Operations that involve a lossy codec inevitably introduce small artefacts at the byte level, but the defaults aim at the sweet spot where output looks or sounds the same to a normal viewer or listener while still being meaningfully smaller or faster than the input.
Can I process multiple files at once with URL Canonicalizer?
URL Canonicalizer processes one input at a time by design — it keeps memory usage predictable on lower-end devices and makes results easier to verify. To handle a folder, run the tool once per file; the page stays loaded between runs and remembers your last-used settings, so the second run is essentially instant.