- Introduction
- Concepts and Design
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SESSION LAYER
- About the Session Layer
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Session
- Session object
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Session object methods
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Session.Platform
- Definition object
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Definition methods
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Session.Desktop
- Definition object
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Definition methods
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Session.Container
- Definition object
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Definition methods
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Functions
- Session events
- Session event codes
- Session states
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CONTENT LAYER
- About the Content Layer
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Fundamental and Reference
- About Fundamental and Reference
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Definition
- Definition object
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Definition methods
- RowHeaders
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Historical Pricing
- About Historical Pricing
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Events
- About Events
- Definition object
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Definition methods
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Summaries
- About Summaries
- Definition object
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Definition methods
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TimeSeries
- Definition object
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Definition methods
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Stream
- Stream object
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Stream methods
- StreamEvents
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Historical Pricing Metadata
- About Historical Pricing Metadata
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Metadata Global
- Definition object
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Definition methods
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Metadata Instrument
- Definition object
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Definition methods
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Metadata Partialbar
- Definition object
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Definition methods
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Metadata Viewlist
- Definition object
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Definition methods
- Event Types
- Adjustments
- Market Sessions
- Timestamp Labels
- Time Series Types
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News
- About News
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News Headlines
- Definition object
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Definition methods
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News Story
- Definition object
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Definition methods
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Pricing
- About Pricing
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Pricing.Definition
- Definition object
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Definition methods
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Pricing.Stream
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Pricing.Chain
- About Pricing.Chain
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Pricing.Chain.Definition
- Definition object
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Definition methods
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Pricing.Chain.Stream
- Stream object
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Stream methods
- Pricing.Chain.Events
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Search
- About Search
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Search.Definition
- Definition object
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Definition methods
- Search View
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SymbolConversion
- About SymbolConversion
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Definition
- Definition object
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Definition methods
- Asset Class
- Asset State
- Country Code
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IPA
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FinancialContracts
- About FinancialContracts
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Definition
- Definition object
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Definition methods
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Bond
- Bond.Definition object
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Bond.Definition methods
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Interfaces & Enumerations
- PricingParameters
- CreditSpreadType
- InflationMode
- QuotationMode
- QuoteFallbackLogic
- VolatilityTermStructureType
- VolatilityType
- ProjectedIndexCalculationMethod
- RedemptionDateType
- BenchmarkYieldSelectionMode
- Rounding
- AmortizationFrequency
- AmortizationItemDefinition
- AmortizationType
- IndexAverageMethod
- IndexCompoundingMethod
- IndexObservationMethod
- RoundingType
- YieldType
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BondFuture
- BondFuture.Definition object
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BondFuture.Definition methods
- BondFuture.UnderlyingContract
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CapFloor
- CapFloor.Definition object
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CapFloor.Definition methods
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Interfaces & Enumerations
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CDS
- CDS.Definition object
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CDS.Definition methods
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Interfaces & Enumerations
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FxCross
- FxCross.Definition object
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FxCross.Definition methods
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Interfaces & Enumerations
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IRSwap
- IRSwap.Definition object
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IRSwap.Definition methods
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Interfaces & Enumerations
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Option
- Option.Definition object
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Option.Definition methods
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Interfaces & Enumerations
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Repo
- Repo.Definition object
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Repo.Definition methods
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Interfaces & Enumerations
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Swaption
- Swaption.Definition object
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Swaption.Definition methods
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Interfaces & Enumerations
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TermDeposit
- TermDeposit.Definition object
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TermDeposit.Definition methods
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Interfaces & Enumerations
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Curves
- About Curves
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ForwardCurve
- ForwardCurve.Definition object
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ForwardCurve.Definition methods
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Interfaces & Enumerations
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ForwardCurves
- ForwardCurves.Definition object
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ForwardCurves.Definition methods
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ZcCurve
- ZcCurve.Definition object
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ZcCurve.Definition methods
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Interfaces & Enumerations
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ZcCurves
- ZcCurves.Definition object
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ZcCurves.Definition methods
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ZcCurveDefinition
- ZcCurveDefinition.Definition object
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ZcCurveDefinition.Definition methods
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ZcCurveDefinitions
- ZcCurveDefinitions.Definition object
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ZcCurveDefinitions.Definition methods
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Interfaces & Enumerations
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Surfaces
- About Surfaces
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Surfaces.Definition
- Surfaces.Definition object
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Surfaces.Definition methods
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Cap
- Cap.Definition object
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Cap.Definition methods
- CalculationParams
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Eti
- Eti.Definition object
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Eti.Definition methods
- CalculationParams
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Fx
- Fx.Definition object
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Fx.Definition methods
- CalculationParams
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Swaption
- Swaption.Definition object
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Swaption.Definition methods
- CalculationParams
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Interfaces & Enumerations
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DatesAndCalendars
- About Dates And Calendars
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AddPeriods
- AddPeriods.Definition object
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AddPeriods.Definition methods
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AddPeriods.Definitions
- Definitions object
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Definitions methods
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CountPeriods
- CountPeriods.Definition object
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CountPeriods.Definition methods
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CountPeriods.Definitions
- Definitions object
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Definitions methods
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DateSchedule
- About DateSchedule
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DateSchedule.Definition
- Definition object
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Definition methods
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Holidays
- Holidays.Definition object
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Holidays.Definition methods
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Holidays.Definitions
- Definitions object
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Definitions methods
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IsWorkingDay
- IsWorkingDay.Definition object
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IsWorkingDay.Definition methods
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IsWorkingDay.Definitions
- Definitions object
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Definitions methods
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Interfaces & Enumerations
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- Content Response
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DELIVERY LAYER
- About the Delivery Layer
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Endpoint Request
- About EndpointRequest
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EndpointRequest.Definition
- Definition object
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Definition methods
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OMM streams
- About OMM streams
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OMMStream.Definition
- Definition object
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Definition methods
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OMMStream
- OmmStream object
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OMMStream methods
- OMMStream events
- OMMStream states
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RDP streams
- About RDP streams
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RDPStream.Definition
- Definition object
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Definition methods
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RDPStream
- RDPStream object
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RDPStream methods
- RDPStream events
- RDPStream response state
- RDPStream states
Introduction
Summary
LSEG Data Libraries are easy-to-use software libraries providing developers with access to the data services of LSEG. These libraries and APIs are designed to provide consistent and easy access to the platform through its different access points, and span several programming languages that target both professional developers and financial coders. LSEG Data Libraries allow you to access LSEG data from the desktop, through local streaming services, or directly to the cloud using your preferred programming language.
LSEG Data Libraries are available for Python, TypeScript or JavaScript and .NET languages in the following libraries:
- LSEG Data Library for Python
- LSEG Data Library for TypeScript/JavaScript
- LSEG Data Library for .NET

Learn more
To learn more about the LSEG Data Libraries, you should connect to the LSEG Developer Community. Register and log in to the LSEG Developer Community portal, for free access to a variety of learning materials like quick start guides, tutorials, user documentation and much more.
Help and Support
If you have any questions regarding the API usage, you may post them on the LSEG Data Q&A Forum.