Error map
EJSONPARSE npm ERR! code EJSONPARSE — Failed to parse json / Unexpected token in JSON at position
npm · layer 7, Build & delivery
Centre: this error. First ring: errors it is linked with (11). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (11)
com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class X and no properties discovered
Jackson can’t serialize the class — it has no public getters/fields, or it’s a Hibernate proxy, or Java 8 date types without the…
com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.ArrayList` from Object value
Jackson found JSON whose shape doesn’t match the target Java type (object vs array, string vs number, missing constructor).
API Error: Malformed JSON in request body (entity.parse.failed / JSON parse error)
The server couldn’t parse the request body as JSON, so it rejected the request before looking at any field.
System.Text.Json: '<' is an invalid start of a value. Path: $ | LineNumber: 0 | BytePositionInLine: 0
The response wasn’t JSON — usually an HTML error page, login redirect, or an empty body was passed to the JSON deserializer.
SyntaxError: Unexpected token < in JSON at position 0
`JSON.parse()` / `response.json()` received something that isn’t JSON — very often an HTML error page.
com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "x", not marked as ignorable
The JSON contains a field your Java class doesn’t have, and Jackson is configured to fail on unknown properties.
System.Text.Json.JsonException: The JSON value could not be converted to System.Int32. Path: $.id
System.Text.Json couldn’t map a JSON value to the target .NET type — e.g. "42" (string) to int, null to a non-nullable type, or w…
Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: <. Path '', line 0, position 0
Json.NET was given text that isn’t valid JSON — commonly HTML, a BOM, or an already-serialized string.
npm ERR! code EOVERRIDE — Override for x conflicts with direct dependency
An "overrides" entry sets a different version for a package you also depend on directly.
npm ERR! Missing script: "start"
The script name you ran isn’t defined in package.json "scripts".
npm ERR! Invalid Version: (semver parse error)
A package.json or lockfile contains a version string that isn’t valid semver.
Two steps away (26)
JsonException: A possible object cycle was detected
System.Text.Json found a reference loop (e.g. Order → Customer → Orders → …) while serialising, usually from EF Core navigation p…
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
A lazy-loaded association was accessed after the Hibernate session/transaction closed.
HttpMessageNotReadableException: JSON parse error / Required request body is missing
Spring couldn’t read the request body into your @RequestBody object.
TypeError: Converting circular structure to JSON
JSON.stringify met an object that references itself (directly or through children).
SyntaxError: Unexpected end of input
The parser reached the end of the code (or JSON) while still expecting more — a missing } ) ] or empty JSON.
json_decode() returns null / JSON_ERROR_SYNTAX: Syntax error
The string passed to json_decode isn’t valid JSON, so PHP returns null.
HTTP 400 Bad Request
The server could not understand the request because its syntax, headers or body are malformed or invalid.
HTTP 415 Unsupported Media Type
The server refuses the request because the body’s Content-Type isn’t one it accepts.
HTTP 411 Length Required
The server refuses a request with a body but no Content-Length header.
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
The text passed to json.loads() isn’t JSON — at char 0 it’s usually empty or HTML.
TypeError: Object of type datetime is not JSON serializable
json.dumps() met a type it doesn’t know how to encode (datetime, Decimal, set, custom objects).
HttpRequestException: The SSL connection could not be established, see inner exception. (AuthenticationException: The remote certificate is invalid)
HttpClient couldn’t complete the TLS handshake — untrusted/self-signed certificate, name mismatch, expired certificate, or TLS ve…
HTTP 404 Not Found
The server can’t find anything at the requested URL.
HTTP 500 Internal Server Error
The server hit an unexpected condition — usually an unhandled exception or misconfiguration in the application.
TypeError: Failed to fetch / NetworkError when attempting to fetch resource
The browser couldn’t complete the request at the network level — CORS, DNS, offline, blocked mixed content, or the server refused…
API Error: Invalid type — expected integer, received string
A request field has the wrong data type — a string where the API expects a number, a number where it expects a boolean, an object…
Swift DecodingError: keyNotFound / typeMismatch / valueNotFound / dataCorrupted
JSONDecoder couldn’t map the JSON to your Codable type — a key is missing, a value has a different type or is null, or the data i…
npm ERR! code ERESOLVE — unable to resolve dependency tree
npm 7+ found conflicting peer dependency requirements and refuses to install a broken tree.
npm ERR! code E404 — 404 Not Found: package@version is not in this registry
npm asked the registry for a package (or version) that doesn’t exist there — a typo, a private/scoped package without auth, or th…
npm ERR! code ETARGET — No matching version found for package@^9.9.9
The version range in package.json doesn’t match any published version of the package.
npm ERR! code ELIFECYCLE / Command failed with exit code 1
An npm script (build, start, test, postinstall) exited with an error. ELIFECYCLE is only the wrapper — the real error is printed…
sh: vite: command not found (npm script)
A tool used in an npm script isn’t installed in node_modules/.bin.
npm ERR! cb() never called!
An old npm crash during install — usually network/cache corruption.
npm ERR! code EINTEGRITY — sha512 integrity checksum failed
A downloaded package’s hash doesn’t match the integrity value in package-lock.json — a corrupted cache, a changed tarball, or a l…
npm ERR! `npm ci` can only install packages when your package.json and package-lock.json are in sync
package-lock.json doesn’t match package.json, so npm ci refuses to install.
npm ERR! The `npm ci` command can only install with an existing package-lock.json or npm-shrinkwrap.json
npm ci needs a committed lockfile and didn’t find one.
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