When writing code for the Web, there are a large number of Web APIs available. Below is a list of all the APIs and interfaces (object types) that you may be able to use while developing your Web app or site.
Web APIs are typically used with JavaScript, although this doesn't always have to be the case.
This is a list of all the APIs that are available.
This is a list of all the interfaces (that is, types of objects) that are available.
AbortControllerAbortSignalAbsoluteOrientationSensorAbstractRangeAccelerometerAesCbcParamsAesCtrParamsAesDerivedKeyParamsAesGcmParamsAesKeyGenParamsAmbientLightSensorAnalyserNodeANGLE_instanced_arraysAnimationAnimationEffectAnimationEventAnimationPlaybackEventAnimationTimelineAttrAudioBufferAudioBufferSourceNodeAudioContextAudioDataAudioDecoderAudioDestinationNodeAudioEncoderAudioListenerAudioNodeAudioParamAudioParamDescriptorAudioParamMapAudioPlaybackStatsAudioProcessingEventAudioScheduledSourceNodeAudioSessionAudioSinkInfoAudioTrackAudioTrackListAudioWorkletAudioWorkletGlobalScopeAudioWorkletNodeAudioWorkletProcessorAuthenticatorAssertionResponseAuthenticatorAttestationResponseAuthenticatorResponseBackgroundFetchEventBackgroundFetchManagerBackgroundFetchRecordBackgroundFetchRegistrationBackgroundFetchUpdateUIEventBarcodeDetectorBarPropBaseAudioContextBatteryManagerBeforeInstallPromptEventBeforeUnloadEventBiquadFilterNodeBlobBlobEventBluetoothBluetoothCharacteristicPropertiesBluetoothDeviceBluetoothRemoteGATTCharacteristicBluetoothRemoteGATTDescriptorBluetoothRemoteGATTServerBluetoothRemoteGATTServiceBluetoothUUIDBroadcastChannelBrowserCaptureMediaStreamTrackBufferedChangeEventByteLengthQueuingStrategyCacheCacheStorageCanMakePaymentEventCanvasCaptureMediaStreamTrackCanvasGradientCanvasPatternCanvasRenderingContext2DCaptureControllerCaretPositionCDATASectionChannelMergerNodeChannelSplitterNodeChapterInformationCharacterBoundsUpdateEventCharacterDataClientClientsClipboardClipboardChangeEventClipboardEventClipboardItemCloseEventCloseWatcherCOEPViolationReportCommandEventCommentCompositionEventCompressionStreamConstantSourceNodeContactAddressContactsManagerContentIndexContentIndexEventContentVisibilityAutoStateChangeEventConvolverNodeCookieChangeEventCookieStoreCookieStoreManagerCountQueuingStrategyCrashReportCrashReportContextCreateMonitorCredentialCredentialsContainerCropTargetCryptoCryptoKeyCryptoKeyPairCSPViolationReportCSSCSSAnimationCSSConditionRuleCSSContainerRuleCSSCounterStyleRuleCSSFontFaceDescriptorsCSSFontFaceRuleCSSFontFeatureValuesMapCSSFontFeatureValuesRuleCSSFontPaletteValuesRuleCSSFunctionDeclarationsCSSFunctionDescriptorsCSSFunctionRuleCSSGroupingRuleCSSImageValueCSSImportRuleCSSKeyframeRuleCSSKeyframesRuleCSSKeywordValueCSSLayerBlockRuleCSSLayerStatementRuleCSSMathClampCSSMathInvertCSSMathMaxCSSMathMinCSSMathNegateCSSMathProductCSSMathSumCSSMathValueCSSMatrixComponentCSSMediaRuleCSSNamespaceRuleCSSNestedDeclarationsCSSNumericArrayCSSNumericValueCSSPageDescriptorsCSSPageRuleCSSPerspectiveCSSPositionTryDescriptorsCSSPositionTryRuleCSSPositionValueCSSPrimitiveValueCSSPropertyRuleCSSPseudoElementCSSRotateCSSRuleCSSRuleListCSSScaleCSSScopeRuleCSSSkewCSSSkewXCSSSkewYCSSStartingStyleRuleCSSStyleDeclarationCSSStylePropertiesCSSStyleRuleCSSStyleSheetCSSStyleValueCSSSupportsRuleCSSTransformComponentCSSTransformValueCSSTransitionCSSTranslateCSSUnitValueCSSUnparsedValueCSSValueCSSValueListCSSVariableReferenceValueCSSViewTransitionRuleCustomElementRegistryCustomEventCustomStateSetDataCueDataTransferDataTransferItemDataTransferItemListDecompressionStreamDedicatedWorkerGlobalScopeDeferredRequestInitDelayNodeDelegatedInkTrailPresenterDeprecationReportDeviceMotionEventDeviceMotionEventAccelerationDeviceMotionEventRotationRateDeviceOrientationEventDevicePostureDirectoryEntrySyncDirectoryReaderSyncDocumentDocumentFragmentDocumentPictureInPictureDocumentPictureInPictureEventDocumentTimelineDocumentTypeDOMErrorDOMExceptionDOMHighResTimeStampDOMImplementationDOMMatrixDOMMatrixReadOnlyDOMParserDOMPointDOMPointReadOnlyDOMQuadDOMRectDOMRectListDOMRectReadOnlyDOMStringListDOMStringMapDOMTokenListDragEventDynamicsCompressorNodeEcdhKeyDeriveParamsEcdsaParamsEcKeyGenParamsEcKeyImportParamsEditContextElementElementInternalsEncodedAudioChunkEncodedVideoChunkErrorEventEventEventCountsEventSourceEventTargetExtendableCookieChangeEventExtendableEventExtendableMessageEventEyeDropperFeaturePolicyFederatedCredentialFederatedCredentialInitFenceFencedFrameConfigFetchEventFetchLaterResultFileFileEntrySyncFileListFileReaderFileReaderSyncFileSystemFileSystemChangeRecordFileSystemDirectoryEntryFileSystemDirectoryHandleFileSystemDirectoryReaderFileSystemEntryFileSystemFileEntryFileSystemFileHandleFileSystemHandleFileSystemObserverFileSystemSyncFileSystemSyncAccessHandleFileSystemWritableFileStreamFocusEventFontDataFontFaceFontFaceSetFontFaceSetLoadEventFormDataFormDataEventFragmentDirectiveGainNodeGamepadGamepadButtonGamepadEventGamepadHapticActuatorGamepadPoseGeolocationGeolocationCoordinatesGeolocationPositionGeolocationPositionErrorGestureEventGPUGPUAdapterGPUAdapterInfoGPUBindGroupGPUBindGroupLayoutGPUBufferGPUCanvasContextGPUCommandBufferGPUCommandEncoderGPUCompilationInfoGPUCompilationMessageGPUComputePassEncoderGPUComputePipelineGPUDeviceGPUDeviceLostInfoGPUErrorGPUExternalTextureGPUInternalErrorGPUOutOfMemoryErrorGPUPipelineErrorGPUPipelineLayoutGPUQuerySetGPUQueueGPURenderBundleGPURenderBundleEncoderGPURenderPassEncoderGPURenderPipelineGPUSamplerGPUShaderModuleGPUSupportedFeaturesGPUSupportedLimitsGPUTextureGPUTextureViewGPUUncapturedErrorEventGPUValidationErrorGravitySensorGyroscopeHashChangeEventHeadersHIDHIDConnectionEventHIDDeviceHIDInputReportEventHighlightHighlightRegistryHistoryHkdfParamsHmacImportParamsHmacKeyGenParamsHMDVRDeviceHTMLAllCollectionHTMLAnchorElementHTMLAreaElementHTMLAudioElementHTMLBaseElementHTMLBodyElementHTMLBRElementHTMLButtonElementHTMLCanvasElementHTMLCollectionHTMLDataElementHTMLDataListElementHTMLDetailsElementHTMLDialogElementHTMLDivElementHTMLDListElementHTMLDocumentHTMLElementHTMLEmbedElementHTMLFencedFrameElementHTMLFieldSetElementHTMLFontElementHTMLFormControlsCollectionHTMLFormElementHTMLFrameSetElementHTMLGeolocationElementHTMLHeadElementHTMLHeadingElementHTMLHRElementHTMLHtmlElementHTMLIFrameElementHTMLImageElementHTMLInputElementHTMLLabelElementHTMLLegendElementHTMLLIElementHTMLLinkElementHTMLMapElementHTMLMarqueeElementHTMLMediaElementHTMLMenuElementHTMLMetaElementHTMLMeterElementHTMLModElementHTMLObjectElementHTMLOListElementHTMLOptGroupElementHTMLOptionElementHTMLOptionsCollectionHTMLOutputElementHTMLParagraphElementHTMLParamElementHTMLPictureElementHTMLPreElementHTMLProgressElementHTMLQuoteElementHTMLScriptElementHTMLSelectedContentElementHTMLSelectElementHTMLSlotElementHTMLSourceElementHTMLSpanElementHTMLStyleElementHTMLTableCaptionElementHTMLTableCellElementHTMLTableColElementHTMLTableElementHTMLTableRowElementHTMLTableSectionElementHTMLTemplateElementHTMLTextAreaElementHTMLTimeElementHTMLTitleElementHTMLTrackElementHTMLUListElementHTMLUnknownElementHTMLVideoElementIDBCursorIDBCursorWithValueIDBDatabaseIDBFactoryIDBIndexIDBKeyRangeIDBObjectStoreIDBOpenDBRequestIDBRecordIDBRequestIDBTransactionIDBVersionChangeEventIdentityCredentialIdentityCredentialErrorIdentityCredentialRequestOptionsIdentityProviderIdleDeadlineIdleDetectorIIRFilterNodeImageBitmapImageBitmapRenderingContextImageCaptureImageDataImageDecoderImageTrackImageTrackListInkInputDeviceCapabilitiesInputDeviceInfoInputEventInstallEventIntegrityViolationReportInteractionContentfulPaintInterestEventIntersectionObserverIntersectionObserverEntryInterventionReportLanguageDetectorLanguageModelLargestContentfulPaintLaunchParamsLaunchQueueLayoutShiftLayoutShiftAttributionLinearAccelerationSensorLocationLockLockManagerMagnetometerManagedMediaSourceManagedSourceBufferMathMLElementMediaCapabilitiesMediaDeviceInfoMediaDevicesMediaElementAudioSourceNodeMediaEncryptedEventMediaErrorMediaKeyMessageEventMediaKeysMediaKeySessionMediaKeyStatusMapMediaKeySystemAccessMediaListMediaMetadataMediaQueryListMediaQueryListEventMediaRecorderMediaRecorderErrorEventMediaSessionMediaSourceMediaSourceHandleMediaStreamMediaStreamAudioDestinationNodeMediaStreamAudioSourceNodeMediaStreamEventMediaStreamTrackMediaStreamTrackAudioSourceNodeMediaStreamTrackEventMediaStreamTrackGeneratorMediaStreamTrackProcessorMediaTrackConstraintsMediaTrackSettingsMediaTrackSupportedConstraintsMerchantValidationEventMessageChannelMessageEventMessagePortMetadataMIDIAccessMIDIConnectionEventMIDIInputMIDIInputMapMIDIMessageEventMIDIOutputMIDIOutputMapMIDIPortMimeTypeMimeTypeArrayMouseEventMouseScrollEventMutationEventMutationObserverMutationRecordNamedNodeMapNavigateEventNavigationNavigationActivationNavigationCurrentEntryChangeEventNavigationDestinationNavigationHistoryEntryNavigationPrecommitControllerNavigationPreloadManagerNavigationTransitionNavigatorNavigatorLoginNavigatorUADataNDEFMessageNDEFReaderNDEFReadingEventNDEFRecordNetworkInformationNodeNodeIteratorNodeListNotificationNotificationEventNotRestoredReasonDetailsNotRestoredReasonsOES_draw_buffers_indexedOfflineAudioCompletionEventOfflineAudioContextOffscreenCanvasOffscreenCanvasRenderingContext2DOrientationSensorOscillatorNodeOTPCredentialOverconstrainedErrorPageRevealEventPageSwapEventPageTransitionEventPaintRenderingContext2DPaintSizePaintWorkletGlobalScopePannerNodePasswordCredentialPasswordCredentialInitPath2DPaymentAddressPaymentManagerPaymentMethodChangeEventPaymentRequestPaymentRequestEventPaymentRequestUpdateEventPaymentResponsePbkdf2ParamsPerformancePerformanceElementTimingPerformanceEntryPerformanceEventTimingPerformanceLongAnimationFrameTimingPerformanceLongTaskTimingPerformanceMarkPerformanceMeasurePerformanceNavigationPerformanceNavigationTimingPerformanceObserverPerformanceObserverEntryListPerformancePaintTimingPerformanceResourceTimingPerformanceScriptTimingPerformanceServerTimingPerformanceSoftNavigationPerformanceTimingPerformanceTimingConfidencePeriodicSyncEventPeriodicSyncManagerPeriodicWavePermissionsPermissionsPolicyViolationReportPermissionStatusPictureInPictureEventPictureInPictureWindowPluginPluginArrayPointPointerEventPopStateEventPositionSensorVRDevicePreferenceManagerPreferenceObjectPresentationPresentationAvailabilityPresentationConnectionPresentationConnectionAvailableEventPresentationConnectionCloseEventPresentationConnectionListPresentationReceiverPresentationRequestPressureObserverPressureRecordProcessingInstructionProfilerProgressEventPromiseRejectionEventPublicKeyCredentialPublicKeyCredentialCreationOptionsPublicKeyCredentialRequestOptionsPushEventPushManagerPushMessageDataPushSubscriptionPushSubscriptionOptionsRadioNodeListRangeReadableByteStreamControllerReadableStreamReadableStreamBYOBReaderReadableStreamBYOBRequestReadableStreamDefaultControllerReadableStreamDefaultReaderRelativeOrientationSensorRemotePlaybackReportingObserverRequestRequestInitResizeObserverResizeObserverEntryResizeObserverSizeResponseRestrictionTargetRsaHashedImportParamsRsaHashedKeyGenParamsRsaOaepParamsRsaPssParamsRTCAudioSourceStatsRTCCertificateRTCCertificateStatsRTCCodecStatsRTCDataChannelRTCDataChannelEventRTCDataChannelStatsRTCDtlsTransportRTCDTMFSenderRTCDTMFToneChangeEventRTCEncodedAudioFrameRTCEncodedVideoFrameRTCErrorRTCErrorEventRTCIceCandidateRTCIceCandidatePairRTCIceCandidatePairStatsRTCIceCandidateStatsRTCIceParametersRTCIceTransportRTCIdentityAssertionRTCInboundRtpStreamStatsRTCOutboundRtpStreamStatsRTCPeerConnectionRTCPeerConnectionIceErrorEventRTCPeerConnectionIceEventRTCPeerConnectionStatsRTCRemoteInboundRtpStreamStatsRTCRemoteOutboundRtpStreamStatsRTCRtpReceiverRTCRtpScriptTransformRTCRtpScriptTransformerRTCRtpSenderRTCRtpTransceiverRTCSctpTransportRTCSessionDescriptionRTCStatsReportRTCTrackEventRTCTransformEventRTCTransportStatsRTCVideoSourceStatsSanitizerSanitizerConfigSchedulerSchedulingScreenScreenDetailedScreenDetailsScreenOrientationScriptProcessorNodeScrollTimelineSecurePaymentConfirmationRequestSecurityPolicyViolationEventSelectionSensorSensorErrorEventSerialSerialPortServiceWorkerServiceWorkerContainerServiceWorkerGlobalScopeServiceWorkerRegistrationShadowRootSharedStorageSharedStorageOperationSharedStorageRunOperationSharedStorageSelectURLOperationSharedStorageWorkletSharedStorageWorkletGlobalScopeSharedWorkerSharedWorkerGlobalScopeSnapEventSourceBufferSourceBufferListSpeechGrammarSpeechGrammarListSpeechRecognitionSpeechRecognitionAlternativeSpeechRecognitionErrorEventSpeechRecognitionEventSpeechRecognitionPhraseSpeechRecognitionResultSpeechRecognitionResultListSpeechSynthesisSpeechSynthesisErrorEventSpeechSynthesisEventSpeechSynthesisUtteranceSpeechSynthesisVoiceStaticRangeStereoPannerNodeStorageStorageAccessHandleStorageEventStorageManagerStylePropertyMapStylePropertyMapReadOnlyStyleSheetStyleSheetListSubmitEventSubtleCryptoSummarizerSVGAElementSVGAngleSVGAnimateColorElementSVGAnimatedAngleSVGAnimatedBooleanSVGAnimatedEnumerationSVGAnimatedIntegerSVGAnimatedLengthSVGAnimatedLengthListSVGAnimatedNumberSVGAnimatedNumberListSVGAnimatedPreserveAspectRatioSVGAnimatedRectSVGAnimatedStringSVGAnimatedTransformListSVGAnimateElementSVGAnimateMotionElementSVGAnimateTransformElementSVGAnimationElementSVGCircleElementSVGClipPathElementSVGComponentTransferFunctionElementSVGDefsElementSVGDescElementSVGDiscardElementSVGElementSVGEllipseElementSVGFEBlendElementSVGFEColorMatrixElementSVGFEComponentTransferElementSVGFECompositeElementSVGFEConvolveMatrixElementSVGFEDiffuseLightingElementSVGFEDisplacementMapElementSVGFEDistantLightElementSVGFEDropShadowElementSVGFEFloodElementSVGFEFuncAElementSVGFEFuncBElementSVGFEFuncGElementSVGFEFuncRElementSVGFEGaussianBlurElementSVGFEImageElementSVGFEMergeElementSVGFEMergeNodeElementSVGFEMorphologyElementSVGFEOffsetElementSVGFEPointLightElementSVGFESpecularLightingElementSVGFESpotLightElementSVGFETileElementSVGFETurbulenceElementSVGFilterElementSVGForeignObjectElementSVGGElementSVGGeometryElementSVGGradientElementSVGGraphicsElementSVGImageElementSVGLengthSVGLengthListSVGLinearGradientElementSVGLineElementSVGMarkerElementSVGMaskElementSVGMetadataElementSVGMPathElementSVGNumberSVGNumberListSVGPathElementSVGPatternElementSVGPointSVGPointListSVGPolygonElementSVGPolylineElementSVGPreserveAspectRatioSVGRadialGradientElementSVGRectSVGRectElementSVGScriptElementSVGSetElementSVGStopElementSVGStringListSVGStyleElementSVGSVGElementSVGSwitchElementSVGSymbolElementSVGTextContentElementSVGTextElementSVGTextPathElementSVGTextPositioningElementSVGTitleElementSVGTransformSVGTransformListSVGTSpanElementSVGUnitTypesSVGUseElementSVGViewElementSyncEventSyncManagerTaskAttributionTimingTaskControllerTaskPriorityChangeEventTaskSignalTextTextDecoderTextDecoderStreamTextEncoderTextEncoderStreamTextEventTextFormatTextFormatUpdateEventTextMetricsTextTrackTextTrackCueTextTrackCueListTextTrackListTextUpdateEventTimeEventTimeRangesToggleEventTouchTouchEventTouchListTrackEventTransformStreamTransformStreamDefaultControllerTransitionEventTranslatorTreeWalkerTrustedHTMLTrustedScriptTrustedScriptURLTrustedTypePolicyTrustedTypePolicyFactoryUIEventURLURLPatternURLSearchParamsUSBUSBAlternateInterfaceUSBConfigurationUSBConnectionEventUSBDeviceUSBEndpointUSBInterfaceUSBInTransferResultUSBIsochronousInTransferPacketUSBIsochronousInTransferResultUSBIsochronousOutTransferPacketUSBIsochronousOutTransferResultUSBOutTransferResultUserActivationValidityStateVideoColorSpaceVideoDecoderVideoEncoderVideoFrameVideoPlaybackQualityVideoTrackVideoTrackGeneratorVideoTrackListViewportViewTimelineViewTransitionViewTransitionTypeSetVirtualKeyboardVisibilityStateEntryVisualViewportVRDisplayVRDisplayCapabilitiesVRDisplayEventVREyeParametersVRFieldOfViewVRFrameDataVRLayerInitVRPoseVRStageParametersVTTCueVTTRegionWakeLockWakeLockSentinelWaveShaperNodeWebGL2RenderingContextWebGLActiveInfoWebGLBufferWebGLContextEventWebGLFramebufferWebGLObjectWebGLProgramWebGLQueryWebGLRenderbufferWebGLRenderingContextWebGLSamplerWebGLShaderWebGLShaderPrecisionFormatWebGLSyncWebGLTextureWebGLTransformFeedbackWebGLUniformLocationWebGLVertexArrayObjectWebSocketWebSocketStreamWebTransportWebTransportBidirectionalStreamWebTransportDatagramDuplexStreamWebTransportDatagramsWritableWebTransportErrorWebTransportReceiveStreamWebTransportSendGroupWebTransportSendStreamWGSLLanguageFeaturesWheelEventWindowWindowClientWindowControlsOverlayWindowControlsOverlayGeometryChangeEventWindowSharedStorageWorkerWorkerGlobalScopeWorkerLocationWorkerNavigatorWorkletWorkletGlobalScopeWorkletSharedStorageWritableStreamWritableStreamDefaultControllerWritableStreamDefaultWriterXMLDocumentXMLHttpRequestXMLHttpRequestEventTargetXMLHttpRequestUploadXMLSerializerXPathEvaluatorXPathExpressionXPathResultXRAnchorXRAnchorSetXRBoundedReferenceSpaceXRCompositionLayerXRCPUDepthInformationXRCubeLayerXRCylinderLayerXRDepthInformationXREquirectLayerXRFrameXRHandXRHitTestResultXRHitTestSourceXRInputSourceXRInputSourceArrayXRInputSourceEventXRInputSourcesChangeEventXRJointPoseXRJointSpaceXRLayerXRLayerEventXRLightEstimateXRLightProbeXRMediaBindingXRPoseXRProjectionLayerXRQuadLayerXRRayXRReferenceSpaceXRReferenceSpaceEventXRRenderStateXRRigidTransformXRSessionXRSessionEventXRSpaceXRSubImageXRSystemXRTransientInputHitTestResultXRTransientInputHitTestSourceXRViewXRViewerPoseXRViewportXRVisibilityMaskChangeEventXRWebGLBindingXRWebGLDepthInformationXRWebGLLayerXRWebGLSubImageXSLTProcessor