JSON to Query String Converter

What this tool is used for

• Turning an object into the query string a GET endpoint expects.
• Building a URL by hand for a curl command from a structured payload.
• Converting a request body into parameters when moving from POST to GET.
• Producing a tracking URL from a set of parameters.
• Checking how your values will look once encoded.

Frequently Asked Questions

How are nested objects handled?

A query string is flat — it has no nesting — so a nested object has to be encoded by convention. Flatten your data before converting, or send it as a JSON body instead. Any bracket or dot syntax is a framework habit rather than a standard.

What gets percent-encoded?

Everything outside the unreserved set: `&`, `=`, `?`, `#`, `/`, `+`, spaces and every non-ASCII character. Spaces become `%20`. Missing the `&` and `=` encoding is what lets one value's content silently create a new parameter.

Is there a length limit?

Not in the spec, but there is in practice. Browsers stop around 2,000 characters reliably, and servers impose their own limits — nginx defaults to 8 KB for the whole request line. Past a few hundred characters, use POST with a body.

How are arrays encoded?

As a repeated key: `tag=a&tag=b`. Every server framework accepts that form, whereas `tag[]=a` is PHP-flavoured and `tag=a,b` requires the receiver to know to split it. Repetition is the only version that is universally understood.

Are numbers and booleans preserved?

No — everything becomes text, because a query string has no types. `{"count": 5}` and `{"count": "5"}` produce identical output, and the receiver has to coerce. That asymmetry is why the conversion back is never quite lossless.

Which array encoding should I use?

It depends on the server. `a=1&a=2` is the widest-supported, `a[]=1&a[]=2` is PHP's convention, and `a=1,2` is common in APIs. None is standard, so the receiver's parser decides — guessing is how arrays arrive as a single string.

Common errors and gotchas

• Not encoding values, so an ampersand or a space in a value breaks the whole string.
• Assuming nested objects have a standard representation, since bracket notation is a convention rather than a rule.
• Producing a URL longer than a server or a proxy will accept.
• Putting sensitive values in a query string, which is logged, cached and sent as a referrer.
• Losing type information, since every query value arrives as a string at the other end.