The State of Web APILanguages in 2016

Jerome Louvel, Chief Geek@jlouvel

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Jérôme LOUVELAbout Jérôme LOUVEL

• Founder, CTO & VP of Products at Restlet

• Restlet Framework creator,first REST framework for Java (2004)

• Contributor to “RESTful Web Services” (O’Reilly, 2007)

• Member of JAX-RS 1.0 expert group (2007 - 2009)

• Co-author of “Restlet in Action” (Manning, 2012)

• InfoQ editor covering Web APIs (since 2014)

• Board member of Open API Initiative

@jlouvel

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• New API Use Cases

• Continuous API Delivery

• API Team Collaboration

Why API Languages?

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API Use Cases

API centric

software

Mobile app

backend

IoTbackend

Micro service

Web app backend

Social bot

backend

Partner API

gateway

PublicAPI

gateway

Automated

workflow

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Continuous API Delivery

DEV

API centric

softwareQA

OPS

BIZ

Develop

QualifyEngage

Operate

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1 | Code-first & Provider driven

Providerteam

Consumer teams

API

Impl

SDK

ClientA

SDK

ClientB

...

...3

1

2

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2 | Contract-first & Provider driven

Providerteam

Consumerteams

Impl

SDK

ClientA

SDK

ClientB

...

...2

1Mock

2

API

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3 | Collaborative Contract-first

Providerteam

Consumer teams

Impl

SDK

ClientA

SDK

ClientB

...

...2

1Mock

2

API

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4 | Contract-first & Consumer Driven

Providerteam

Consumerteams

Impl

SDK

ClientA

SDK

ClientB

...

...2

1Mock

2

APIMockAPI

Impl

MockAPI

Impl

ServicesData

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5 | Contract-first & Consumer Owned

Providerteam

Consumer teams

Impl

SDK

ClientA

SDK

ClientB

...

...2

1Mock

2

APIMockAPI

Impl

MockAPI

Impl

Data Services

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API Team Collaboration

Owne

r

Developer

Writer

Tester Oper

ator

APITeam

Manager

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Impact on API development

• New types of APIs- internal & external APIs- mini & micro APIs- experience APIs

• Number of APIs increases- channels growth- history of versions- microservices pattern- quality of service

• → Industrialization needed- automated workflows- better tooling- importance of API languages

API Platform

Micro APIs(domain data & logic)

Mini APIs(domain services)

Experience APIs(backends)

User Interfaces(frontends)

Public APIs(gateways)

End-users

Micro APIs(external SaaS)

Partner devs

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• OAS

• RAML

• API Blueprint

• Alternatives

Which API Language?

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Current state• Version 2.0 widely adopted with strong tooling support (fka Swagger Spec)• Basis of contribution to the OpenAPI Initiative (OAI)• Strongest market traction

Upcoming 3.0 version• Structural improvements• Request Parameters• Protocol and Payload• Documentation, Security, Path definitions• Release planned for first half of 2017

Learn more• https://www.openapis.org/blog• https://www.openapis.org/specification/repo• https://www.infoq.com/news/2016/01/tony-tam-oai-initiative-swagger• https://www.infoq.com/articles/open-api-initiative-update

OpenAPI Specification (OAS)

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Content, Callbacks, Links, etc.

Overview of changes in OAS 3.0

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Evolution of Swagger

2015

Specificationdonated

Open sourceframework

Commercialcloud tool

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Current state• Version 0.8 adopted with good tooling support• Good market traction, especially in larger enterprises• Strong support by MuleSoft, a well established software vendor

Latest 1.0 version• Built-in data typing, examples, libraries, annotations, overlays and extensions• Stronger design and reusability capabilities than OAS• Tooling partially available but progressing

Learn more• http://www.raml.org/• https://github.com/raml-org/raml-spec/• https://www.infoq.com/news/2016/08/raml-1.0-mulesoft

RESTful API Modeling Language (RAML)

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Current state• Version 1A9 adopted with good tooling support• Good market traction, especially during by API design teams• Support by Apiary, an API startup

Latest version• Built-in data typing based on Markdown → MSON• Still young compared to more mature schema languages such as JSON Schema• ABP creator, Zdenek Nemec, recently left Apiary → see his talk at APIdays on what’s next• Apiary is a member of OAI and also supports OAS in its tooling

Learn more• https://apiblueprint.org/• https://github.com/apiaryio/api-blueprint/• https://www.infoq.com/news/2015/05/api-blueprint-progress

API Blueprint

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• RAPID-ML- Created by RepreZen- Data/Domain-Driven API Modeling- RepreZen API Studio

• Google API Discovery format- Supports Google Discovery Service- Not used elsewhere much- Google is a founding member of OAI and supports OAS

• WADL- The pioneer, created by Sun Microsystems in 2005- XML based alternative to WSDL- Still used in Apigee products for example

Alternatives

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Languages are Abstraction Layers

Hardware

Assembly languages

System languages

Application languages

Web API languages

software level, driversNASM / TASM

OS level, high performanceC / C++ / C# / Go

productivity, portability, business logicJava / PHP / Visual Basic

web scale, interoperability, integration, DSLsOAS / RAML / API Blueprint

lowest level, machine codex86 / CISC / RISC / etc.1st generation

2nd generation

3rd generation

4th generation

3rd generation

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Maturity levels of API Languages

• 1) Describe API contract- endpoints, resources, operations, representations- enable the generation of:

• client SDKs & server skeletons• documentation• test scenarios• mock servers

• 2) Implement API- wrap regular applications written with classic languages- compose lower-level APIs into higher-level APIs- integration purpose at web scale

• 3) Operate API- provide the infrastructure to deliver the API- access to data and services

Lower levellanguages

API delivery network

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• For Design

• For Testing

• Maturity levels

API Language IDEs

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Design IDE - SmartBear SwaggerHub

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Design IDE - MuleSoft API Designer

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Design IDE - Apiary Editor

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Design IDE - Restlet Studio

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Design IDE - Restlet Studio

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Test IDE - Postman

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Test IDE - Paw

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Test IDE - Restlet Client (DHC)

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API Centric Software - Maturity Levels

Level 4Behavior

driven

Level 3 - Test driven

(replace UI testing, blue green deployment)

Level 2 - Contract driven

(provider driven, collaborative, consumer driven)

Level 1 - Implementation driven

(code driven, data driven, service driven)

API centric software is software

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Our API challenges

● 1 | Converge API languages○ OpenAPI Initiative as standardization body○ extend OAS with specialized languages (design, testing, operation)○ move innovation to upper levels○ accelerate tooling ecosystem

● 2 | Better API workflows○ integrate API & DevOps tools

○ integrate Design & Test

○ integrate Design & Operate

○ Integrate Test & Operate

→ A whole new API Stack is emerging!

Thank youQ&A