API Error — 404 (RFC 9457 problem+json)
A 404 error body in RFC 9457 (problem+json) form, with type, title, status, detail, and instance — for testing structured error handling and problem-detail parsers.
{
"type": "https://example.com/errors/not-found",
"title": "Not Found",
"status": 404,
"detail": "No user exists with id 999.",
"instance": "/v1/users/999"
}
Specifications
- Format
- application/problem+json
- Status
- 404
- Spec
- RFC 9457
What is a .json file?
JSON (JavaScript Object Notation) is a lightweight, text-based data-interchange format representing objects, arrays, strings, numbers, booleans, and null. It is language-independent, human-readable, and the dominant format for web APIs and configuration. It requires a single well-formed root value.
How to use this file
Use an example JSON file to test parsers and serializers, schema validation, Unicode and number-precision handling, and API request or response processing.
How to use this file for testing
“API Error — 404 (RFC 9457 problem+json)” is a deterministic Novus Examples fixture for API testing, Conversion testing. OpenAPI/Swagger specs, GraphQL SDL, JSON Schema, paginated and problem+json error payloads, and webhook samples — for testing API clients, mock servers, contract tests, and schema validators.
Documented properties for this file: application/problem+json. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Data fixtures document their exact quirks — delimiters, encodings, null handling, schema, and row counts — in the spec table. Point your parser or importer at the file and assert it handles the documented edge cases; clean and deliberately-messy siblings make before/after diffs straightforward.
Code examples
import json
with open("error-404.json") as f:
data = json.load(f)
print(type(data), len(data))Related files
- jsonAPI Error — 422 Validation (JSON)A 422 validation-error response with a machine-readable list of field errors — for testing form-validation surfacing and error mapping.
- jsonAPI Response — Users Page 1 (JSON)Page 1 of a paginated JSON API response (users), with page metadata and a `hasMore` flag. Paired with page 2 for testing pagination and infinite-scroll logic.
- jsonAPI Response — Users Page 2 (JSON)Page 2 (the final page) of a paginated JSON API response. Paired with page 1 for testing pagination, `hasMore` handling, and list merging.
- graphqlGraphQL Schema (SDL)A GraphQL Schema Definition Language (SDL) file with queries, a mutation, object/input types, and an enum — for testing GraphQL schema parsers, linters, and code generators.
- jsonOpenAPI 3.1 Spec (JSON)A small but complete OpenAPI 3.1 description (two paths, three schemas) in JSON — for testing API tooling, mock servers, client codegen, and docs generators.
- yamlOpenAPI 3.1 Spec (YAML)The same OpenAPI 3.1 description in YAML — the format most API definitions ship in. Paired with the JSON twin for testing YAML↔JSON conversion and spec parsers.
Generated by generation/data_dev_fixtures.py. Free for any use, no attribution required — license.