With the rise of Microservice Architectures and rich mobile and web applications, APIs are more important than ever. Come learn how to tackle modern API design challenges with GraphQL, an open-source API query language used by Facebook, Amazon, Microsoft, Twitter, Virgin Trains, and more.

1. S U M M I T
LONDON

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Building Modern APIs with
GraphQL
Robert Zhu
Principal Technical Evangelist
Amazon Web Services
@rbzhu
S e s s i o n I D

3. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Robert Zhu
Principal Technical Evangelist
Amazon Web Services
@rbzhu

4. S U M M I T © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.

5. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
What is GraphQL?
• Request (GraphQL doc) -> Response (JSON)
• Language Specification
• Schema (domain-specific)
• Server Implementation

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GraphQL is not
• A Graph database query language (*)
• A client-side state management solution
• A solution for binary streams
• Facebook Graph API
• Limited to specific database(s)
• Limited to JavaScript/NodeJS on the backend
• Limited to use with React/Relay/Web
• Limited to HTTP

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GraphQL operations
Query  Read
Mutation  Write
Subscription  Observe Event

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Query Structure
query GetBooksForAuthor($id: ID!) {
author(id: $id) {
givenName,
nationality,
books {
title
isbn
}
}
}

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Query Structure
query GetBooksForAuthor($id: ID!) {
author(id: $id) {
givenName,
nationality,
books {
title
isbn
}
}
}

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Query Structure
query GetBooksForAuthor($id: ID!) {
author(id: $id) {
givenName,
nationality,
books {
title
isbn
}
}
}

11. S U M M I T © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Query Structure
query GetBooksForAuthor($id: ID!) {
author(id: $id) {
givenName,
nationality,
books {
title
isbn
}
}
}

12. S U M M I T © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Query Structure
query GetBooksForAuthor($id: ID!) {
author(id: $id) {
givenName,
nationality,
books {
title
isbn
}
}
}

13. S U M M I T © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Query Structure
query GetBooksForAuthor($id: ID!) {
author(id: $id) {
givenName,
nationality,
books {
title
isbn
}
}
}

14. S U M M I T © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Query Structure
query GetBooksForAuthor($id: ID!) {
author(id: $id) {
givenName,
nationality,
books {
title
isbn
}
}
}

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History of GraphQL
• 2012- Built to support Facebook mobile apps
• 2015- GraphQL open sourced
• 2018- GraphQL Foundation

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API Technologies
• REST
• SOAP
• gRPC
• Apache Thrift
• OpenAPI/Swagger
• JSON-LD
• HAL
• OData
• … and more

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REST GraphQL

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REST GraphQL
Shared Definition No Yes

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REST GraphQL
Shared Definition No Yes
Conceptual Model Resources Graphs

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REST GraphQL
Shared Definition No Yes
Conceptual Model Resources Graphs
Organization Federated Centralized

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REST GraphQL
Shared Definition No Yes
Conceptual Model Resources Graphs
Organization Federated Centralized
Related Ops Yes No

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REST GraphQL
Shared Definition No Yes
Conceptual Model Resources Graphs
Organization Federated Centralized
Related Ops Yes No
Introspection No Yes

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REST GraphQL
Shared Definition No Yes
Conceptual Model Resources Graphs
Organization Federated Centralized
Related Ops Yes No
Introspection No Yes
Data Typing Weak Strong

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REST GraphQL
Shared Definition No Yes
Conceptual Model Resources Graphs
Organization Federated Centralized
Related Ops Yes No
Introspection No Yes
Data Typing Weak Strong
Real-time No Yes

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Challenges for Modern APIs
• Efficiency
• Predictability
• Versioning
• Security
• Documentation
• Tooling
• Caching
• Database Integration
• Real-time
• … and many more

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Efficiency
• Overfetching: response contained too much data.
• Underfetching: response did not contain enough data. Make another
network request.
• Networks suck
• Read 1 MB from SSD: 400 μs
• Packet US <-> EU: 150 ms

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Efficiency
• Avoid Overfetching and Underfetching.
• Clients to declare all the data they need in a single network request.
• Reduces the need for client-side joins, error handling, and retry logic.

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Type Safety
• Predictability
• Native clients
• Code gen

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Domain Modeling
• Domain Driven Design
• Eric Evans, 2004
• Shared Language

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Versioning
• Don’t

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Tooling & Documentation
• GraphiQL provides documentation via introspection query
• Docs are never out-of-date
• IDE integrations via graphql-language-service
• GraphQL for VSCode

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Authentication and Authorization
• Authentication
• Who are you?
• Authorization
• Do you have permission?

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HTTP Custom Protocol over TCP
Authentication
REST GraphQL RPC
Business Logic
Authentication
Persistence
Authorization

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HTTP Custom Protocol over TCP
Authentication
REST GraphQL RPC
Business Logic
Authentication
Persistence
Authorization

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When to use GraphQL
Cumulative
functionality
time
no design
good design
Design payoff line

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Getting GraphQL into Production
DO NOT
• Build a complete schema upfront
• Try to replace your REST API in one push
• Place business logic in the GraphQL layer
DO
• Educate your team
• Choose a solution that fits with your stack
• Build a simple query first (read-only)
• Gradually layer in features like auth/mutations
• Gradually expand schema

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Advanced use cases
• API Gateway
• 1st party vs 3rd party
• Service-to-service
• Domain Modeling: schema-first
• Persisted Queries
• Subscriptions
• Live Queries

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Ecosystem
• AWS AppSync
• https://aws.amazon.com/appsync
• Apollo
• https://www.apollographql.com/
• Prisma
• https://www.prisma.io/
• Hasura
• https://hasura.io/

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Resources
• Start here: http://graphql.org
• Community: http://graphql.org/community/
• Demo: https://github.com/robzhu/tsgraphql-starwars
• AppSync: https://aws.amazon.com/appsync/

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Thank you!
S U M M I T © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.
Robert Zhu
Principal Technical Evangelist
Amazon Web Services
@rbzhu

43. © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I TS U M M I T © 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.