HTTP response code
An HTTP status code is a standardized three-digit value in an HTTP response that indicates the outcome of processing the corresponding request.
Learn Go with Pocket-Sized Projects
An HTTP status code is a standardized numeric response indicator describing the result of an HTTP request.
- How it is used
- Guides whether an HTTP client parses a response and what result a service handler sends.
- How deep it goes
- Defines five status classes and works through client classification, handler write order, and tests without cataloguing every code.
- Examples
- Uses an exchange-rate client, a POST /games handler, curl output, and a response-recorder assertion.
- What you can do after
- Apply it via Go net/http to classify responses, set handler statuses before writing bodies, and assert codes in tests.
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ASP.NET Core in Action, 3e
An HTTP status code is a three-digit code in an HTTP response that indicates the result of processing the corresponding request.
- How it is used
- Uses response codes to communicate request outcomes to browsers and API clients.
- How deep it goes
- Defines five code classes and works through response helpers, while directing readers to RFC 9110 for the full standardized list.
- Examples
- Shows missing static files returning 404 and minimal API handlers choosing 200, 201, 400, or 404.
- What you can do after
- Apply it via ASP.NET Core Results and TypedResults to return codes that match common API outcomes.
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The Design of Web APIs, Second Edition
An HTTP status code is a numeric code in an HTTP response that indicates the result of processing a request.
- How it is used
- Maps REST operation outputs to standardized success and error signals in HTTP responses.
- How deep it goes
- Explains status classes, selection criteria, common operation recipes, response placement, and OpenAPI description.
- Examples
- Uses product creation, catalog search, reads, updates, deletions, missing resources, and server failures.
- What you can do after
- Apply it via HTTP and OpenAPI to choose interoperable responses for successful, invalid, missing, and failed operations.
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Build Financial Software with Generative AI (From Scratch)
An HTTP status code is a numeric response indicator that communicates the outcome of an HTTP request.
- How it is used
- Uses HTTP response codes to verify API endpoint reachability during Postman and automated tests.
- How deep it goes
- Defines successful 200 responses and demonstrates assertions, but stops short of covering other status-code classes.
- Examples
- Uses /files and /api/v1/companies requests with Postman and Python endpoint-test assertions.
- What you can do after
- Diagnose endpoint connectivity by asserting a 200 response in Postman or an automated API test.
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Spring in Action, Sixth Edition
An HTTP status code is a three-digit code in an HTTP response that indicates the result of processing a request.
- How it is used
- Communicates the outcome of REST requests so clients can distinguish successful retrieval, creation, deletion, and missing resources.
- How deep it goes
- Shows controller-level status selection with ResponseEntity and @ResponseStatus, without detailing HTTP protocol internals.
- Examples
- Contrasts a missing taco's misleading 200 with 404, then uses 201 for taco creation and 204 for order deletion.
- What you can do after
- Apply it via Spring MVC to return accurate statuses for resource lookup, creation, and deletion.
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Acing the CCNA Exam: Volume 2 Advanced Networking and Security
An HTTP status code is a three-digit numeric code in an HTTP response that indicates the result of the corresponding request.
- How it is used
- Communicates the result of an HTTP request during REST API client-server exchanges.
- How deep it goes
- Defines five categories and common codes, but does not detail every code or implementation mechanism.
- Examples
- Uses ACL-rule creation with POST and 201 Created, plus examples including 200, 301, 403, 404, and 500.
- What you can do after
- Evaluate HTTP request results by interpreting the response code and its category.
Contract Testing in Action
An HTTP status code is a numeric code in an HTTP response indicating the result of processing a request.
- How it is used
- Defines API response expectations within consumer-driven contract scenarios and migration from integration tests.
- How deep it goes
- Explains concrete response-code expectations and contract assertions, but does not detail HTTP status-code categories or protocol internals.
- Examples
- Uses movie retrieval, creation, duplication, deletion, Supertest assertions, and Pact interactions as concrete examples.
- What you can do after
- Apply it via Pact to specify and verify API response-code expectations across consumer and provider tests.
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Go in Practice, Second Edition
An HTTP status code is a three-digit code in an HTTP response indicating the outcome of processing a request.
- How it is used
- Communicates request outcomes between HTTP servers and clients, especially for errors, authentication, retries, and custom API responses.
- How deep it goes
- Descends from status ranges to Go constants, response inspection, MIME checks, and custom errors, but leaves retry implementation incomplete.
- Examples
- Uses Go handlers, curl requests, status inspection, range classification, and custom JSON error conversion.
- What you can do after
- Diagnose/debug HTTP failures by classifying response codes, checking content types, authenticating, retrying selectively, and returning structured Go errors.
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gRPC Microservices in Go
A gRPC status code is a predefined code that identifies the outcome or error condition of an RPC.
- How it is used
- Guides interservice error handling and determines client actions such as retrying, timing out, or opening a circuit.
- How deep it goes
- Defines common gRPC codes and demonstrates structured validation errors, but does not detail the complete status-code catalog.
- Examples
- Uses order creation, invalid identifiers, quotas, missing orders, duplicate users, and Go field-violation handling.
- What you can do after
- Diagnose/debug with gRPC by classifying failures, reading structured validation details, and selecting appropriate resilience actions.
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The Well-Grounded Python Developer: How the pros use Python and Flask
An HTTP status code is a numeric response code indicating the outcome of an HTTP request.
- How it is used
- Uses response codes to verify that a browser request reached a running web application and was processed successfully.
- How deep it goes
- Defines the code and explains 200 as “OK,” without cataloging other response-code categories.
- Examples
- Uses a browser request to a local Flask route, a “Hello World!” response, and a terminal log ending in 200.
- What you can do after
- Evaluate whether a local Flask request was handled successfully by reading the browser result and server log.
.NET in Action, Second Edition
An HTTP status code is a three-digit response code indicating the outcome of an HTTP request.
- How it is used
- Controls endpoint outcomes when successful operations or invalid request options require different HTTP responses.
- How deep it goes
- Explains default 200 responses, conditional 404 responses, built-in ActionResults, and file responses without detailing the full MVC pattern.
- Examples
- Uses ASCII-art font validation for 404 handling and barcode generation for JPEG file responses.
- What you can do after
- Apply it via ASP.NET Core Results to return success, not-found, content, or file responses from minimal API endpoints.
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Related concepts
- 500 Internal Server Errorincludes · 500 Internal Server Error is an HTTP status code indicating that the server encountered an unexpected condition that prevented it from fulfilling a request.
- contractpart of · An API contract is a specification of the operations, data, and behavioral expectations that govern interactions between software components.
- HTTP responsepart of · An HTTP response is a protocol message sent by a server to a client after an HTTP request, containing status information, headers, and optionally a body.
- generationpart of · Generation is the computational production of outputs from supplied inputs or context, often by applying a model to produce predictions or new content.
- 403 Forbiddenincludes · 403 Forbidden is an HTTP response status indicating that the server understood a request but refuses to authorize the requested access or operation.
- HTTP 404 errorincludes · An HTTP 404 Not Found response indicates that the server did not find a current representation of the requested resource or is unwilling to disclose that one exists.
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