10 Common JSON Errors and How to Fix Them
If you work with JSON regularly, you’ve hit an “invalid JSON” error before — and probably more than once wondered exactly what’s wrong when the message itself isn’t much help. The good news is that JSON errors come from a surprisingly small set of root causes. Once you know what to look for, most broken JSON takes seconds to fix rather than minutes of squinting at brackets.
Frequently Asked Questions
Why does my JSON error message not tell me exactly what’s wrong?
Many JSON parsers report only a character position, not a plain-English description — which is technically accurate but not very human-friendly. A good validator converts that raw position into a line and column number so you can jump straight to the problem instead of counting characters.
What’s the fastest way to check JSON for errors before deploying it?
For quick manual checks, an online validator is usually fastest since there’s no setup involved. For automated checks in a pipeline or script, most languages have a built-in JSON parser (like Python’s json module) that will raise an error on invalid input, which you can catch programmatically.
Can invalid JSON still “work” sometimes?
In some cases, yes — certain parsers are lenient and will silently tolerate things like trailing commas or duplicate keys. This is actually more dangerous than a hard failure, because your data can behave unpredictably across different systems: one API might accept JSON that another rejects outright, since they’re not required to enforce the specification identically.
Do all JSON errors stop the whole file from working?
Yes — unlike some more forgiving formats, JSON parsing is all-or-nothing. A single syntax error anywhere in the document, even in a small nested value, will cause the entire file to fail parsing rather than just that one section.