book

Learning API Styles

by Lukasz Dynowski, Marcin Dulak

July 2025

Intermediate to advanced

414 pages

10h 22m

English

O'Reilly Media, Inc.

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Why We Wrote This BookWho Should Read This BookWhat’s in This BookWhat’s Not in This BookWeather Forecast ServiceConventions Used in This BookUsing Code ExamplesO’Reilly Online LearningHow to Contact UsAcknowledgmentsAcknowledgments from Lukasz DynowskiAcknowledgments from Marcin Dulak
What Is an API?Network-Based APIsConcepts of API CommunicationMessageTransmission ModesSynchronous and Asynchronous Communication TypesHistory of APIsWhy APIs?What Are API Styles?API as a ProductAPI LifecyclePlanningDesignImplementationTestingDeploymentMaintenanceRetirementAPI Governance, Management, and PlatformFuture of APIsSummary
Examples of API Design PatternsAPI LanguageAPI NamingEvolving APIsAPI VersioningEncodingFilteringCounting and SortingPaginationLong-Running TasksRequest DeduplicationRequest RetryRate LimitingCachingDeletionAPI SecurityOWASP Top 10 API SecurityExamples of API Security PatternsEncryption, Authentication, and AuthorizationSanitization and ValidationScraping MitigationAPI Design Best PracticesSummary
Network ProtocolsSocket APITCP/IP and the OSI ModelImplementing TCP ECHO ServiceNetwork Lab SetupTCP ECHO ServiceTCP ECHO ServerTCP ECHO Client with NetcatTCP ECHO Client with ScapySecurityTCP ECHO Client with OpenSSLExercisesSummary
What Is Hypertext?HTTP Lab SetupHTTP/0.9HTTP and HTML in ActionHTTP/1.0HTTP Message Headers and BodyHTTP in a BrowserHow DNS Affects Browser ConnectionsParallel TCP Connections in a BrowserLimitations of TCPTCP Head-of-Line BlockingTCP Slow Start and Congestion AvoidanceHTTP/1.1HTTP Connection PersistenceHTTP/2HTTP/2 Frames and StreamsHTTP/3QUIC 1-RTT Connection EstablishmentExercisesSummary
HTTP, Resource, and URIClient-Server CommunicationOrigins of RESTAPI Maturity ModelsRESTful, RESTless, or RESTIs Being RESTless Good Enough?ImplementationAPI EndpointsAPI VersioningCRUDPaginationRate LimitingCachingSecurityJSON Web TokenTransport Layer SecurityDocumentationOpenAPI SpecificationThree Approaches to API SpecificationTrade-OffsWhen to Use RESTExercisesSummary
Problems with RESTThinking in GraphsOrigins of GraphQLGraphQL Versus RESTGraphQL ConstructsHow GraphQL WorksImplementationGraphiQLExecuting MutationsCRUDReadCreate, Update, DeleteSecurityAttacking GraphQLAuthenticationDocumentationTrade-OffsWhen to Use GraphQLExercisesSummary
What Is a Web Feed?Why Web Feeds?Evolution of Web FeedsWhat Is Atom Feed?ImplementationReading FeedsSecurityTrade-OffsExercisesSummary
Remote Procedure CallOrigins of gRPCProtobuf SerializationCode GenerationgRPC ECHO Server and ClientThe Four RPC TypesProtobuf Wire FormatImplementationgRPC Atom Feed Enricher ServiceSecurityDocumentationTrade-OffsWhen to Use gRPCExercisesSummary

What Are Webhooks?Origins of WebhooksIncoming and Outgoing WebhooksIntegration and Data FlowImplementationSecurityDocumentationTrade-OffsWhen to Use WebhooksExercisesSummary
WebSocket and WebSocket APIWebSocket Opening HandshakeImplementationWebSocket ECHO Client and ServerWebSocket ProtocolWebSocket Weather Alert ServerWebSocket Weather Alert ClientSecurityOrigin ValidationTrusted Host SecurityJSON Web TokenTransport Layer SecurityDocumentationTrade-OffsWhen to Use WebSocketExercisesSummary
What Is Messaging?What Is a Queue?Messaging PatternsWork Queue PatternPublish-Subscribe PatternRouting PatternTopics PatternRequest-Response PatternImplementationWork QueueSecurityUnencrypted Messages in TransitMessages Encrypted in TransitAuthentication and AuthorizationDocumentationAsyncAPI SpecificationAsyncAPI DocumentationMessage VersioningTrade-OffsWhen to Use MessagingExercisesSummary

Overview

An application programming interface (API) enables data exchange in systems such as web applications, microservices, and IoT devices. In this hands-on book, authors Lukasz Dynowski and Marcin Dulak show software developers and architects how to design and implement REST, GraphQL, gRPC, webhooks, WebSocket, messaging APIs, and more.

This book looks at the most popular API styles from a network, application, and architecture perspective. You'll learn how to determine the appropriate type of API for your application use case and how to tackle design decisions along the way. You'll also learn the trade-offs between various APIs and acquire practical knowledge of how to implement them.