Free developer tools that run in your browser
Goongoonalo Tools is a growing suite of focused utilities for people who build and debug on the web. No account, no install, no upload — open a tool and start working. We are starting with streaming.
- 0
- Accounts required
- 2
- Streaming protocols
- 100%
- Runs client-side
- Free
- Now and later
Everything in one place
Each tool does one job properly. Pick the one you need — the detailed breakdowns are further down this page.
Stream Checker
Play, debug and inspect any HLS or MPEG-DASH stream
Paste an .m3u8 or .mpd URL and it plays immediately in a real hls.js / dash.js engine — no signup, no install. Watch every player event as it fires, read the raw manifest, inspect quality ladders and encryption keys, and tune the ABR engine live. When a stream is blocked by CORS or a referer check, route it through the built-in proxy and keep debugging.
Reach for it when you need to
- Verify a new encoder or packager output before it ships
- Reproduce a customer playback bug with the exact headers they send
- Check whether a CDN is serving the right ladder and segment durations
- Confirm low-latency HLS is actually low latency
- Debug why a stream plays in VLC but not in the browser
What is inside
Dual streaming engines
hls.js for HTTP Live Streaming and dash.js for MPEG-DASH, with automatic protocol detection from the URL. Progressive MP4 falls back to native playback.
Manifest & MPD inspector
Read the fetched playlist with syntax highlighting, browse the parsed quality ladder as a table, and pull out every #EXT-X-KEY entry. Copy or download the manifest in one click.
Live event & network log
Every engine event, fragment load, level switch and error, timestamped and filterable by severity or free text. Expand any row for the raw payload, or export the whole session as JSON.
Stats for nerds
A floating HUD with resolution, framerate, codecs, current and average bitrate, buffer health, live-edge latency, dropped frames and the engine's bandwidth estimate.
CORS proxy, referer & headers
Toggle the server-side proxy to bypass CORS, spoof a Referer, and attach arbitrary request headers such as Authorization or a custom token — exactly what geo-locked and token-signed streams need.
DRM & encrypted playback
Configure ClearKey, Widevine or PlayReady with your own license server URL to verify a protected stream end to end.
ABR & engine fine-tuning
Turn on low-latency HLS, set buffer lengths, seed the initial bandwidth estimate, cap levels to player size, or defer loading — then watch how the ladder behaves.
Sample streams & saved profiles
Curated public test streams to start from, plus every stream you launch saved locally with its protocol, referer and proxy settings so you can jump straight back in.
HLS & DASH Academy
Learn how adaptive streaming actually works
A practical, no-fluff reference for HTTP adaptive streaming. It walks the full delivery path from encoder to player, compares HLS with MPEG-DASH honestly, dissects real manifests tag by tag, and explains the ABR decisions that make playback smooth or terrible. Written for engineers who need to ship, not pass an exam.
Reach for it when you need to
- Onboard onto a video team without reading four RFCs first
- Decide between HLS, DASH or both for a new product
- Look up what an unfamiliar manifest tag means, fast
- Understand a bug report before you try to reproduce it
What is inside
Delivery architecture
Follow a stream from source through encoder, packager, origin and CDN to the player, and see where latency and failure actually come from.
HLS vs MPEG-DASH
A side-by-side comparison of manifests, segment formats, DRM support and device reach, so you can pick the right one instead of shipping both by default.
Manifest anatomy
Master playlists, media playlists and MPD structure broken down line by line, with annotated real-world examples.
Searchable tag database
Every significant #EXT-X- tag and DASH element with its scope, what it does and a working example — filterable as you type.
Adaptive bitrate explained
How players estimate bandwidth, when they switch levels, and how buffer targets and level caps change the viewer's experience.
Low-latency HLS
Partial segments, blocking playlist reloads and preload hints — what LL-HLS requires from your packager and CDN to hit sub-three-second glass-to-glass.
Troubleshooting playbook
The failures you will actually hit — CORS, mixed content, codec mismatches, stalled buffers, key errors — and how to tell them apart from the logs.
Tools we wanted to exist
Most free online tools are ad-choked, half-broken, or a signup form wearing a trench coat. These are not.
No account, ever
No signup wall, no email capture, no usage quota. Open a tool and use it — the same on your tenth visit as your first.
Runs in your browser
The work happens client-side. Your URLs, files and settings stay on your machine unless you explicitly opt into the CORS proxy.
Built for real debugging
Not toy demos. Real engines, raw manifests, full event logs and the header controls you need when a stream misbehaves in production.
Free, and staying free
These started as tools we needed ourselves. Publishing them costs us little and saves everyone else an afternoon.
What we are building next
Early sketches, not promises with dates. If one of these would save you time, that moves it up the list.
Subtitle Converter
Convert and re-time SRT, VTT and TTML captions
Media Inspector
Read codec, container and track metadata from a media file
CORS & Headers Tester
See exactly which headers a URL returns, and why the browser blocked it
Questions people actually ask
If something here is unclear, the answer is probably worth adding — the list grows with the suite.
Do I need an account to use these tools?
No. Every tool is open to everyone, with no signup, no email and no trial. Open the page and start working.
Does my stream URL or media get uploaded to your servers?
Not by default. The tools run in your browser and talk to the stream directly. The one exception is the optional CORS proxy in Stream Checker: when you switch it on, requests for that stream are relayed through our server so the browser will accept them. Leave the proxy off and nothing touches our backend.
Which streaming formats does Stream Checker support?
HLS (.m3u8) through hls.js, MPEG-DASH (.mpd) through dash.js, and progressive MP4 through native browser playback. Protocol is auto-detected from the URL, and you can force it if the extension lies.
My stream works in VLC but not here. Why?
Almost always CORS, a Referer check, or mixed content. Browsers enforce rules VLC does not. Turn on the proxy, set the Referer the origin expects, and add any auth headers — then read the event log to see exactly which request failed.
Can I test DRM-protected streams?
Yes. Stream Checker supports ClearKey, Widevine and PlayReady — supply your license server URL and the browser's own CDM handles the rest. Support ultimately depends on the browser you are using.
Is saved data stored anywhere I should worry about?
Your stream history and favourites live in your own browser's local storage. They never leave your device, and clearing site data removes them.
What tools are coming next?
A subtitle converter for SRT, VTT and TTML, a media metadata inspector, and a CORS and headers tester. The suite grows based on what people actually ask for.