Unexpected character in found when decoding object value
This message comes from ujson on CPython 3.12.3. In this registry it is produced by 4 distinct mistakes. Positions in the real message vary with your input; the causes do not.
Causes
What produces this message
Hexadecimal number in JSON
Input
{"a": 0x1F}Exact message: Unexpected character in found when decoding object value
Fix: Convert to decimal, or quote it as a string if the hex form is the meaningful representation.
Missing comma between object members
Input
{"a": 1 "b": 2}Exact message: Unexpected character in found when decoding object value
Fix: Add a comma between the two members.
Trailing comma in a JSON object
Input
{"a": 1,}Exact message: Unexpected character in found when decoding object value
Fix: Delete the comma before the closing brace.
Unclosed object — unexpected end of JSON input
Input
{"a": 1Exact message: Unexpected character in found when decoding object value
Fix: Verify you received the whole payload. Compare the byte count against Content-Length, and check for proxy or log truncation.
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 property name enclosed in double quotes: line L column C (char N) |
| Gson | Expected name at line L column C path $…Unterminated object at line L column C path $…java.io.EOFException: End of input at line L column C path $… |
| Gson JsonParser (lenient off) | Expected name at line L column C path $…Unterminated object at line L column C path $…java.io.EOFException: End of input at line L column C path $… |
| JSON5 | JSON5: invalid character '\"' at 1:9JSON5: invalid end of input at 1:8 |
| JSON::PP | , or } expected while parsing object/hash, at character offset N (before "…")unexpected end of string while parsing JSON string, at character offset N (before "…") |
| Jackson ObjectMapper | Unexpected character ('"' (code 34)): was expecting comma to separate Object entriesUnexpected character ('x' (code 120)): was expecting comma to separate Object entriesUnexpected character ('}' (code 125)): was expecting double-quote to start field nameUnexpected end-of-input: expected close marker for Object (start marker |
| JavaScriptCore JSON.parse | JSON Parse error: Expected '}'JSON Parse error: Property name must be a string literal |
| Newtonsoft.Json JsonConvert | After parsing a value an unexpected character was encountered: ". Path 'a', line L, position N.Unexpected end when deserializing object. Path 'a', line L, position N. |
| Newtonsoft.Json JsonTextReader | After parsing a value an unexpected character was encountered: ". Path 'a', line L, position N. |
| Ruby JSON.parse | unexpected token at '…' |
| SpiderMonkey JSON.parse | JSON.parse: end of data after property value in object at line L column C of the JSON dataJSON.parse: expected ',' or '}' after property value in object at line L column C of the JSON dataJSON.parse: expected double-quoted property name at line L column C of the JSON data |
| System.Text.Json Deserialize | '"' is invalid after a value. Expected either ',', '}', or ']'. Path: $ | LineNumber: L | BytePositionInLine: C.'1' is an invalid end of a number. Expected a delimiter. Path: $ | LineNumber: L | BytePositionInLine: C.'x' is an invalid end of a number. Expected a delimiter. Path: $ | LineNumber: L | BytePositionInLine: C.The JSON object contains a trailing comma at the end which is not supported in this mode. Change the reader options. Path: $ | LineNumber: L | BytePositionInLine: C. |
| System.Text.Json JsonDocument | '"' is invalid after a value. Expected either ',', '}', or ']'. LineNumber: L | BytePositionInLine: C.'1' is an invalid end of a number. Expected a delimiter. LineNumber: L | BytePositionInLine: C.'x' is an invalid end of a number. Expected a delimiter. LineNumber: L | BytePositionInLine: C.The JSON object contains a trailing comma at the end which is not supported in this mode. Change the reader options. LineNumber: L | BytePositionInLine: C. |
| V8 JSON.parse | Expected ',' or '}' after property value in JSON at position N (line L column C)Expected double-quoted property name in JSON at position N (line L column C) |
| encoding/json Unmarshal | invalid character '"' after object key:value pairinvalid character 'x' after object key:value pairinvalid character '}' looking for beginning of object key stringunexpected end of JSON input |
| hjson | End of input while parsing an object (missing '}') at line L,11End of input while parsing an object (missing '}') at line L,15End of input while parsing an object (missing '}') at line L,7 |
| json-bigint | Bad stringExpected ',' instead of '"'Expected ',' instead of ''Expected ',' instead of 'x' |
| json_decode | Syntax error |
| orjson | trailing comma is not allowed: line L column C (char N)unexpected character, expected ',' or '}': line L column C (char N)unexpected end of data: line L column C (char N) |
| serde_json::from_str | EOF while parsing an object at line L column Cexpected `,` or `}` at line L column Ctrailing comma at line L column C |
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.