Port Number Reference
Reference of well-known TCP/UDP port numbers for web, email, database, file transfer, and other services.
How it works
- 1Configure your options above
- 2Click "Generate" — processing happens in your browser
- 3Copy or download the result
What to do next
About Port Number Reference
Port Number Reference is a free, in-browser developer tool. Reference of well-known TCP/UDP port numbers for web, email, database, file transfer, and other services. The page exposes a small surface — input, controls, output — so a first-time visitor can complete the job without reading documentation.
Port Number Reference is implemented on top of standard browser APIs. Inputs are read from the file picker or drop zone, decoded in the browser, processed, and re-encoded into the output format. Files up to 0 MB are well within the comfort zone of any modern browser.
Port Number Reference runs the entire transformation inside your browser. The file is read by JavaScript running in the page, processed in-memory by standard browser APIs, and written back as a download. The browser is the runtime; the page is the interface. You can confirm what the tool does by opening the developer-tools Network tab during a run — the only requests are for the page's own static assets.
Anyone who works with developer utility on a casual basis — frontend developers prepping fixtures, data analysts wrangling JSON, students learning new languages — finds Port Number Reference 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.
Port Number Reference works well as a bookmarked utility you reach for when you need it. The first visit shows you what the tool does; the second is when you realise it is a low-friction option for the task and worth keeping in your tab list.
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, Port Number Reference 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.
Port Number Reference is honest about scope: it handles a single, well-defined developer utility step. Specialist edge-case work — uncommon formats, very large inputs, or pipelines that need scripting — is what dedicated desktop apps are for. This page handles the common case quickly.
The download is delivered as a clearly named file the moment processing completes — no email link, no "your result will be ready in 5 minutes" queue, no expiry timer. The file is generated in your browser and saved by your browser's normal download flow.
Some context on why Port Number Reference exists in this form: modern File APIs, high-performance JavaScript engines, and well-maintained open-source libraries now make it possible to perform developer utility work entirely in the browser. Port Number Reference is built on top of that capability, which is why a single page can host the full pipeline.
As a single-page tool, Port Number Reference stays focused on one developer utility step. Multi-step workflows are composed by chaining adjacent tools — each tool produces a standard file the next one can read directly, so a longer pipeline is just a sequence of short tab-and-tab visits.
If you want to get the most out of Port Number Reference, three small habits help. Drag-and-drop is faster than the file picker once you get used to it. The keyboard shortcut for downloading the result is whatever your browser uses for "save link as," because the result is a normal download. And if you are working on a sensitive file, processing in an Incognito or Private window is a good extra layer — it leaves no trace in browser history when the tab closes.
Common gotchas worth flagging: the supported formats are listed in the upload area. The 0 MB ceiling is per-file, not per-session; you can run as many separate jobs as you like, but a single oversized input will be rejected on load.
Port Number Reference is one of many single-purpose tools in the catalog. Each is built around the same single-page model. Use this one, close the tab, and come back the next time you need the same job done. None of the tools require prior knowledge of the others — each page is self-contained.
How it works
- 1Open the Port Number Reference workspace above. The interface is a single page, so there is nothing to navigate.
- 2Drop a developer file onto the upload area, or click to pick one from your device.
- 3Adjust the options to match what you need. Sensible defaults cover the most common case, so you can usually skip this step.
- 4Click to start the job. The engine (standard browser APIs) processes the input in the page; you can watch the progress indicator until it completes.
- 5Grab the output as soon as the run completes. You can also copy the result instead of downloading if the next tool in your workflow accepts pasted input.
- 6Run additional jobs as needed. The same controls and defaults apply on every run.
Common use cases
- Pretty-print a minified blob during incident triage using Port Number Reference.
- Inspect a payload during local development without writing a script.
- Hash a string for a quick reproducibility check.
- Format a noisy log line into something a teammate can read.
- Validate a config blob before pushing to staging.
- Convert between data formats while wiring up an integration.
- Inspect a regex against a test string before committing it.
- Generate boilerplate from a single specification line.
- Compare two API responses to spot a regression.
FAQ
What are well-known ports?
Ports 0-1023 assigned by IANA for standard services like HTTP (80), HTTPS (443), SSH (22), and DNS (53).
TCP vs UDP?
TCP provides reliable, ordered delivery (HTTP, SSH). UDP is faster but unreliable (DNS, NTP, streaming).
Registered ports?
Ports 1024-49151 are registered for specific services (MySQL 3306, PostgreSQL 5432, Redis 6379).
Dynamic/ephemeral ports?
Ports 49152-65535 are used temporarily by client applications for outbound connections.
Can I use any port?
Technically yes, but using standard ports makes services discoverable and avoids firewall issues.
Private?
Yes — reference generated locally.
Does Port Number Reference require a browser extension or plug-in?
No installation is needed. Port Number Reference runs as a normal web page, with no browser extension, no native helper, and no separate desktop client to download. That is partly a privacy choice — extensions can request broad permissions, while a regular page is sandboxed by default — and partly a convenience one: you can use Port Number Reference on any computer you have temporary access to without leaving anything installed on it.
Why did Port Number Reference reject my input?
Failures usually fall into one of three buckets: the input is in an unsupported format, the input is over the size cap, or the input is structurally malformed (a truncated download, a partial export, or a stream the engine does not recognise). The first two are easy to confirm — check that your file is in a supported format and that it is below 0 MB. For the third, opening the file in its native viewer first is the fastest way to confirm the source is intact.
Is Port Number Reference keyboard accessible?
Port Number Reference uses native HTML controls wherever possible, which means keyboard navigation, focus rings, and screen-reader labels work the way the platform expects. The drop zone accepts files via the keyboard-accessible file picker as well as drag-and-drop, and result downloads use standard browser download flows. If you spot an accessibility gap, Favtoo treats it as a bug worth fixing.
Which browsers are supported by Port Number Reference?
Port Number Reference 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.
Is there a programmatic version of Port Number Reference?
Port Number Reference is a browser-only tool by design and does not expose a hosted API. The reason is the same as the privacy story: there is no Favtoo backend doing the work, so there is no service to call. If you need to script the same transformation, the underlying engine (standard browser APIs) is open-source and can be used directly from your own code.
Will Port Number Reference keep working in a year?
Port Number Reference 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.
Is Port Number Reference licensed for business use?
Port Number Reference can be used for personal and commercial work alike — there is no separate "business" licence to purchase. The output you generate is yours to use however you want, including in client deliverables, internal documents, or commercial products. Favtoo's only ask is fair, individual use; the tool is not designed to be embedded as a backend service or wrapped behind an API for resale.