18 chars · 2 lines
Waiting for input
YAML implicit key troubleshooting
The preloaded flow sequence splits foo and its colon across two lines. In strict YAML parsing, an implicit flow mapping key needs its key/value indicator on the same line so the parser can identify the pair unambiguously. This tool is free to use. No account or payment is required.
Last updated
A formatter or manual edit may wrap compact YAML for readability, but not every token boundary can move freely. Implicit keys have stricter line rules because the parser must distinguish a mapping pair from neighboring scalar content.
If a key/value pair is too long to keep readable in compact form, a block mapping usually makes the relationship clearer. Reserve flow syntax for short structures where punctuation and key boundaries remain obvious.
The corrected pair keeps foo and its colon together on one line.
items: [foo
: bar]items: [foo: bar]Common questions
It is a mapping key written without the explicit ? key indicator, using the following colon to identify the key/value pair.
Strict YAML limits implicit key syntax so the parser can determine the key boundary unambiguously. Splitting a flow key from its colon can violate that rule.
Yes. Rewriting compact flow mappings as block mappings often makes long keys and values easier to read and edit safely.
Debugging a specific YAML issue? Browse YAML troubleshooting.