GraphQL Query Builder
Build GraphQL queries and mutations with fields, arguments, and variables interactively.
How it works
- 1Configure your options above
- 2Click "Generate" — processing happens in your browser
- 3Copy or download the result
What to do next
About GraphQL Query Builder
GraphQL Query Builder is part of a collection of single-purpose developer utility tools. Build GraphQL queries and mutations with fields, arguments, and variables interactively. Each tool is intentionally narrow — it does one thing well rather than offering many overlapping features — which makes the common path predictable and the result easy to verify before you download or copy it.
Architecturally, GraphQL Query Builder 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.
GraphQL Query Builder parses your file with standard browser APIs entirely inside the browser, applies the options you selected, and returns a download. The processing has no network step, which means a slow or intermittent connection does not slow down the work — once the page is loaded, only your CPU and RAM are involved.
The heaviest users of GraphQL Query Builder tend to be engineers debugging API payloads, site reliability engineers triaging logs and students learning new languages. Each group brings slightly different expectations to the tool, but the same single-page architecture serves every one of them with the same response time.
GraphQL Query Builder 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.
The 0 MB ceiling on input size is the only fixed limit. Output files are produced in standard formats that every common viewer recognises, and the tool runs the same way regardless of how many times you have used it during the session.
For multi-step jobs, GraphQL Query Builder sits next to Postman to cURL Converter, REST API Checklist, and API Rate Limit Calculator. None of them depend on each other — you can use GraphQL Query Builder on its own — but together they cover the common variations of the task this page exists to handle.
GraphQL Query Builder 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 output handed back by GraphQL Query Builder is the output file. If you would prefer to keep the result in the browser instead of downloading it, you can copy it from the result panel and paste it directly into another tab — useful when the next tool in your workflow expects pasted text rather than a file.
Some background on the design choices behind GraphQL Query Builder: every option you see on the page is there because a real workflow needs it, and every option that is not shown has been deliberately omitted to keep the common case fast. The bias is toward minimal-but-complete.
As a single-page tool, GraphQL Query Builder 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.
Useful patterns when working with GraphQL Query Builder: keep the input file open in another tab so you can compare against the result; give the output file a descriptive name when saving so you can find it later (the default name is sensible but generic); and treat each run as independent — the tool has no concept of "history", which means you cannot accidentally pollute one job with leftovers from another.
If GraphQL Query Builder appears to hang, the engine is almost certainly still working — large inputs simply take longer to process inside a browser than they would on a server with multi-core scheduling. For inputs near the 0 MB cap, give it up to a minute on a typical laptop before assuming something is stuck.
GraphQL Query Builder 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 GraphQL Query Builder workspace above. The interface is a single page, so there is nothing to navigate.
- 2Add your developer input by dropping it onto the page or browsing for it.
- 3Pick any non-default settings you need. Most users leave the defaults alone for the first run and only revisit if the result needs tuning.
- 4Trigger processing. standard browser APIs reads your input, applies the transformation, and writes the result back into the page.
- 5Download the result. The file is generated in your browser and saved through your normal download flow.
- 6Run additional jobs as needed. The same controls and defaults apply on every run.
Common use cases
- Hash a string for a quick reproducibility check using GraphQL Query Builder.
- Generate a quick fixture without leaving the browser.
- Inspect a payload during local development without writing a script.
- Generate boilerplate from a single specification line.
- Convert between data formats while wiring up an integration.
- Encode binary content for transport in a JSON body.
- Decode a token to confirm its claims during a debugging session.
- Format a noisy log line into something a teammate can read.
FAQ
What operations are supported?
Query, mutation, and subscription operation types.
Can I add nested fields?
Yes — use dot notation or add child fields to create nested selections.
Variables support?
Define typed variables ($id: ID!, $name: String) and reference them in arguments.
Fragments?
Fragment syntax is not generated, but you can manually add them to the output.
Formatting?
Output is properly indented and formatted for readability.
Private?
Yes — built locally in your browser.
Does GraphQL Query Builder need an internet connection to run?
Once the page is loaded, GraphQL Query Builder can complete jobs without an active internet connection — the engine is bundled with the page, so there is no per-job network call. The initial page load does require a connection (to fetch the static assets), but after that you can disconnect entirely and the tool will still work. This is a side-effect of the local-first architecture, not a deliberate "offline mode" feature.
What input formats are supported by GraphQL Query Builder?
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.
How accessible is the GraphQL Query Builder interface?
GraphQL Query Builder 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.
Does GraphQL Query Builder reduce quality of the result?
GraphQL Query Builder is built to preserve quality wherever the underlying developer 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 GraphQL Query Builder?
GraphQL Query Builder 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.
What does the error message in GraphQL Query Builder mean?
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.
Which browsers are supported by GraphQL Query Builder?
GraphQL Query Builder 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.
What is the maximum file size for GraphQL Query Builder?
Inputs are capped at 0 MB per file, which keeps memory usage stable across phones, tablets and older laptops. You can run GraphQL Query Builder as often as you need; every run produces a full-quality result.
Why is my browser prompting me when I open GraphQL Query Builder?
GraphQL Query Builder only needs the standard web platform — file picker access for the inputs you choose to load, and optionally clipboard access if you copy the result rather than downloading it. There is no microphone, camera, geolocation or background-permission request, because none of those are needed for the work the tool does.