invalid number at line L column C
This message comes from serde_json::from_str on Rust (serde_json 1.x). In this registry it is produced by 3 distinct mistakes. Positions in the real message vary with your input; the causes do not.
Causes
What produces this message
Bare minus sign where a number was expected
Input
{"a": -}Exact message: invalid number at line 1 column 8
Fix: Emit `null` or `0` when the value is missing, and check your template for an unsubstituted placeholder.
Leading zero in a JSON number
Input
{"a": 013}Exact message: invalid number at line 1 column 8
Fix: Quote it. `"013"` is a string and keeps its padding; `13` is a number and does not.
Trailing decimal point in a JSON number
Input
{"a": 1.}Exact message: invalid number at line 1 column 9
Fix: Write `1.0` or `1`.
Same bug, other languages
What other parsers say about the same input
If a colleague reports a different message for what looks like the same file, this is why.
| Parser | Message for the same inputs |
|---|---|
| CPython json.loads | Expecting ',' delimiter: line L column C (char N)Expecting value: line L column C (char N) |
| JSON5 | JSON5: invalid character '1' at 1:8JSON5: invalid character '}' at 1:8 |
| JSON::PP | malformed number (leading zero must not be followed by another digit), at character offset N (before "…")malformed number (no digits after decimal point), at character offset N (before "…")malformed number (no digits after initial minus), at character offset N (before "…") |
| Jackson ObjectMapper | Invalid numeric value: Leading zeroes not allowedUnexpected character ('}' (code 125)) in numeric value: Decimal point not followed by a digitUnexpected character ('}' (code 125)) in numeric value: expected digit (0-9) to follow minus sign, for valid numeric value |
| JavaScriptCore JSON.parse | JSON Parse error: Expected '}'JSON Parse error: Invalid digits after decimal pointJSON Parse error: Invalid number |
| Newtonsoft.Json JsonConvert | Input string '-' is not a valid number. Path 'a', line L, position N. |
| Newtonsoft.Json JsonTextReader | Input string '-' is not a valid number. Path 'a', line L, position N. |
| Ruby JSON.parse | unexpected token at '…' |
| SpiderMonkey JSON.parse | JSON.parse: expected ',' or '}' after property value in object at line L column C of the JSON dataJSON.parse: unexpected non-digit at line L column C of the JSON dataJSON.parse: unterminated fractional number at line L column C of the JSON data |
| System.Text.Json Deserialize | '}' is invalid within a number, immediately after a decimal point ('.'). Expected a digit ('0'-'9'). Path: $ | LineNumber: L | BytePositionInLine: C.'}' is invalid within a number, immediately after a sign character ('+' or '-'). Expected a digit ('0'-'9'). Path: $ | LineNumber: L | BytePositionInLine: C.Invalid leading zero before '1'. Path: $ | LineNumber: L | BytePositionInLine: C. |
| System.Text.Json JsonDocument | '}' is invalid within a number, immediately after a decimal point ('.'). Expected a digit ('0'-'9'). LineNumber: L | BytePositionInLine: C.'}' is invalid within a number, immediately after a sign character ('+' or '-'). Expected a digit ('0'-'9'). LineNumber: L | BytePositionInLine: C.Invalid leading zero before '1'. LineNumber: L | BytePositionInLine: C. |
| V8 JSON.parse | No number after minus sign in JSON at position N (line L column C)Unexpected number in JSON at position N (line L column C)Unterminated fractional number in JSON at position N (line L column C) |
| encoding/json Unmarshal | invalid character '1' after object key:value pairinvalid character '}' after decimal point in numeric literalinvalid character '}' in numeric literal |
| hjson | End of input while parsing an object (missing '}') at line L,10End of input while parsing an object (missing '}') at line L,8 |
| json-bigint | Bad number |
| json_decode | Syntax error |
| orjson | no digit after decimal point: line L column C (char N)no digit after sign: line L column C (char N)number with leading zero is not allowed: line L column C (char N) |
Sources
Standards this registry is checked against
- RFC 8259 (STD 90) — The JavaScript Object Notation (JSON) Data Interchange Format, T. Bray, Ed., 2017. The IETF Internet Standard for JSON. Obsoletes RFC 7159 and RFC 4627.
- ECMA-404, 2nd edition — The JSON Data Interchange Syntax, Ecma International, 2017. Ecma’s grammar for JSON. A normative reference of RFC 8259; the two define the same syntax.
- The Unicode Standard — The Unicode Standard, Core Specification, The Unicode Consortium, current. Normatively referenced by RFC 8259 for the definition of a character.
- IEEE 754-2019 — IEEE Standard for Floating-Point Arithmetic, IEEE, 2019. Referenced by RFC 8259 §6 as the basis for its interoperability guidance on numbers.
Only standards bodies and peer-reviewed venues are cited. Error strings on this site are observed by executing each parser; the standards above define what the parser is reacting to.