Rapidly iterating across platforms using server-driven UI

Often companies with large mobile user bases find that they have to balance rapid iteration with the amount of work involved in launching and coordinating a product on multiple platforms (web, native Android, and native iOS).

Faced with exactly this question for the Airbnb reservation system, we designed a server-driven UI framework for web, iOS, and Android that allows us to launch new types of reservations on all platforms with a simple backend change. It uses a commonly shared API that is parsed on the client and rendered into a set of corresponding components supported on all platforms.

The talk also covers the ways other teams at Airbnb are using server-driven UI to do cross-platform product development.

Transcript

1. Rapidly iterating across platforms using server-driven UI LAURA KELLY @heylaurakelly
2. • Android Engineer @ Airbnb • Previously front-end web • Trip platform team • Powerlifter • Whiskey connoisseur @heylaurakelly Who I am
3. 1. The problem we were trying to solve 2. Why server-driven UI fit the bill 3. Deep-dive into Android implementation 4. Case studies from Airbnb @heylaurakelly Outline
4. @heylaurakelly Airbnb is adding new products all the time Homes
5. Airbnb is adding new products all the time @heylaurakelly Homes Experiences
6. Airbnb is adding new products all the time @heylaurakelly Homes Experiences Restaurants
7. @heylaurakelly Airbnb is adding new products all the time Homes Experiences Restaurants Coworking Spaces
8. @heylaurakelly Homes Experiences Restaurants Coworking Spaces We were rebuilding nearly the same screen, multiplying our efforts across the codebase
9. @heylaurakelly
10. …and across platforms @heylaurakelly
11. There’s got to be a better way. @heylaurakelly
12. What would an ideal system be? @heylaurakelly
13. Easy to understand @heylaurakelly
14. Flexible to adapt to designers @heylaurakelly
15. Launch without a Play Store release @heylaurakelly
16. Minimize repetition @heylaurakelly
17. Easy to maintain @heylaurakelly
18. Server-driven UI @heylaurakelly
19. What is server-driven UI? {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls": [ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 },
 {
 "type": "row:map",
 "address": "1234 Main Street"
 }
 ]
 } Example API response @heylaurakelly
20. @heylaurakelly {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls": [ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 },
 {
 "type": "row:map",
 "address": "1234 Main Street"
 }
 ]
 } API Response
21. @heylaurakelly {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls": [ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 },
 {
 "type": "row:map",
 "address": "1234 Main Street"
 }
 ]
 } API Response
22. @heylaurakelly API Response {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 }
23. @JsonSubTypes({ @JsonSubTypes.Type( value = CarouselDataModel.class, name = “row:carousel” ), @JsonSubTypes.Type( value = TitleRowDataModel.class, name = “row:title” ), @JsonSubTypes.Type( value = ActionRowDataModel.class, name = “row:action" ) . . .
 }) {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 } @heylaurakelly Map to Data Models API Response
24. @heylaurakelly export default { 'row:carousel': CarouselRow, 'row:title': TitleRow, 'row:action': ActionRow, . . .
 } Frontend Web Code {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 } API Response
25. @JsonSubTypes({ @JsonSubTypes.Type( value = CarouselDataModel.class, name = “row:carousel” ), @JsonSubTypes.Type( value = TitleRowDataModel.class, name = “row:title” ), @JsonSubTypes.Type( value = ActionRowDataModel.class, name = “row:action" ) . . .
 }) Map to Data Models {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 } API Response UI Rendering @heylaurakelly
26. @heylaurakelly @JsonSubTypes({ @JsonSubTypes.Type( value = CarouselDataModel.class, name = “row:carousel” ), @JsonSubTypes.Type( value = TitleRowDataModel.class, name = “row:title” ), @JsonSubTypes.Type( value = ActionRowDataModel.class, name = “row:action" ) . . .
 }) Map to Data Models {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 } API Response UI Rendering
27. @JsonSubTypes({ @JsonSubTypes.Type( value = CarouselDataModel.class, name = “row:carousel” ), @JsonSubTypes.Type( value = TitleRowDataModel.class, name = “row:title” ), @JsonSubTypes.Type( value = ActionRowDataModel.class, name = “row:action" ) . . .
 }) Map to Data Models {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 } API Response UI Rendering @heylaurakelly
28. @JsonSubTypes({ @JsonSubTypes.Type( value = CarouselDataModel.class, name = “row:carousel” ), @JsonSubTypes.Type( value = TitleRowDataModel.class, name = “row:title” ), @JsonSubTypes.Type( value = ActionRowDataModel.class, name = “row:action" ) . . .
 }) Map to Data Models {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 } API Response UI Rendering @heylaurakelly
29. @JsonSubTypes({ @JsonSubTypes.Type( value = CarouselDataModel.class, name = “row:carousel” ), @JsonSubTypes.Type( value = TitleRowDataModel.class, name = “row:title” ), @JsonSubTypes.Type( value = ActionRowDataModel.class, name = “row:action" ) . . .
 }) Map to Data Models {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 } API Response UI Rendering Carousel Title Row Action Row Rendering Framework @heylaurakelly
30. @JsonSubTypes({ @JsonSubTypes.Type( value = CarouselDataModel.class, name = “row:carousel” ), @JsonSubTypes.Type( value = TitleRowDataModel.class, name = “row:title” ), @JsonSubTypes.Type( value = ActionRowDataModel.class, name = “row:action" ) . . .
 }) Map to Data Models {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 } API Response UI Rendering Title Row Action Row Rendering Framework Map Row @heylaurakelly
31. @JsonSubTypes({ @JsonSubTypes.Type( value = CarouselDataModel.class, name = “row:carousel” ), @JsonSubTypes.Type( value = TitleRowDataModel.class, name = “row:title” ), @JsonSubTypes.Type( value = ActionRowDataModel.class, name = “row:action" ) . . .
 }) Map to Data Models {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls":[ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 } ...
 ]
 } API Response UI Rendering Action Row Title Row Rendering Framework Map Row @heylaurakelly
32. Benefits we saw after building the system @heylaurakelly
33. Build once @heylaurakelly
34. Easily accommodates changing minds @heylaurakelly
35. Reuse existing UI component libraries @heylaurakelly
36. Iterate, reconfigure, and experiment on our own time @heylaurakelly
37. Android Deep Dive @heylaurakelly
38. 1. JSON from server JSON @heylaurakelly
39. 1. JSON from server JSON 2. Parse network response ArrayList<Row> rows( ) @heylaurakelly
40. 1. JSON from server JSON 2. Parse network response 3. Parse row subtypes ArrayList<Row> rows( ) LinkRow MapRow TitleRow HostAvatarRow @heylaurakelly
41. 1. JSON from server JSON 2. Parse network response 3. Parse row subtypes 4. Configure UI models ArrayList<Row> rows( ) LinkRow MapRow TitleRow HostAvatarRow ReservationController ReservationFragment @heylaurakelly
42. 1. JSON from server JSON ReservationController ReservationFragment 2. Parse network response 3. Parse row subtypes 4. Configure UI models ArrayList<Row> rows( ) LinkRow MapRow TitleRow HostAvatarRow 5. Render components @heylaurakelly
43. 1. JSON from server JSON 2. Parse network response 3. Parse row subtypes 4. Configure UI models ArrayList<Row> rows( ) LinkRow MapRow TitleRow HostAvatarRow 5. Render components ReservationController ReservationFragment @heylaurakelly
44. @AutoValue @JsonDeserialize(builder = AutoValue_Reservation.Builder.class) public abstract class Reservation { @JsonProperty public abstract String primary_key(); @JsonProperty public abstract ArrayList<RowDataModel> rows(); ... } @heylaurakelly 2. Parse network response
45. @AutoValue @JsonDeserialize(builder = AutoValue_Reservation.Builder.class) public abstract class Reservation { @JsonProperty public abstract String primary_key(); @JsonProperty public abstract ArrayList<RowDataModel> rows(); ... } @heylaurakelly 2. Parse network response
46. JSON ArrayList<Row> rows( ) LinkRow MapRow TitleRow HostAvatarRow 1. JSON from server 2. Parse network response 3. Parse row subtypes 4. Configure UI models 5. Render components ReservationController ReservationFragment @heylaurakelly
47. @heylaurakelly @JsonTypeInfo(...) @JsonSubTypes({ @JsonSubTypes.Type(value = LinkRowDataModel.class, name = "row:link"), @JsonSubTypes.Type(value = MapRowDataModel.class, name = "row:map"), @JsonSubTypes.Type(value = TitleRowDataModel.class, name = “row:title”), @JsonSubTypes.Type(value = HostAvatarRowDataModel.class, name = “row:host_avatar”) ... }) public interface RowDataModel extends Parcelable { ... } 3. Parse row subtypes
48. @heylaurakelly @JsonTypeInfo(...) @JsonSubTypes({ @JsonSubTypes.Type(value = LinkRowDataModel.class, name = "row:link"), @JsonSubTypes.Type(value = MapRowDataModel.class, name = "row:map"), @JsonSubTypes.Type(value = TitleRowDataModel.class, name = “row:title”), @JsonSubTypes.Type(value = HostAvatarRowDataModel.class, name = “row:host_avatar”) ... }) public interface RowDataModel extends Parcelable { ... } 3. Parse row subtypes
49. @heylaurakelly @JsonTypeInfo(...) @JsonSubTypes({ @JsonSubTypes.Type(value = LinkRowDataModel.class, name = "row:link"), @JsonSubTypes.Type(value = MapRowDataModel.class, name = "row:map"), @JsonSubTypes.Type(value = TitleRowDataModel.class, name = “row:title”), @JsonSubTypes.Type(value = HostAvatarRowDataModel.class, name = “row:host_avatar”) ... }) public interface RowDataModel extends Parcelable { ... } 3. Parse row subtypes
50. @heylaurakelly @JsonTypeInfo(...) @JsonSubTypes({ @JsonSubTypes.Type(value = LinkRowDataModel.class, name = "row:link"), @JsonSubTypes.Type(value = MapRowDataModel.class, name = "row:map"), @JsonSubTypes.Type(value = TitleRowDataModel.class, name = “row:title”), @JsonSubTypes.Type(value = HostAvatarRowDataModel.class, name = “row:host_avatar”) ... }) public interface RowDataModel extends Parcelable { ... } 3. Parse row subtypes
51. @heylaurakelly @AutoValue @JsonDeserialize(builder = AutoValue_LinkRowDataModel.Builder.class) @JsonTypeName("row:link") public abstract class LinkRowDataModel implements RowDataModel { @JsonProperty public abstract String id(); @JsonProperty public abstract String title(); @JsonProperty public abstract String app_url(); @JsonProperty public abstract String loggingId(); ... } 3. Parse row subtypes
52. @heylaurakelly @AutoValue @JsonDeserialize(builder = AutoValue_LinkRowDataModel.Builder.class) @JsonTypeName("row:link") public abstract class LinkRowDataModel implements RowDataModel { @JsonProperty public abstract String id(); @JsonProperty public abstract String title(); @JsonProperty public abstract String app_url(); @JsonProperty public abstract String loggingId(); ... } 3. Parse row subtypes
53. @heylaurakelly @AutoValue @JsonDeserialize(builder = AutoValue_LinkRowDataModel.Builder.class) @JsonTypeName("row:link") public abstract class LinkRowDataModel implements RowDataModel { @JsonProperty public abstract String id(); @JsonProperty public abstract String title(); @JsonProperty public abstract String app_url(); @JsonProperty public abstract String loggingId(); ... } 3. Parse row subtypes
54. JSON ArrayList<Row> rows( ) LinkRow MapRow TitleRow HostAvatarRow 1. JSON from server 2. Parse network response 3. Parse row subtypes 4. Configure UI models 5. Render components ReservationController ReservationFragment @heylaurakelly
55. Render with Epoxy HTTPS://GITHUB.COM/AIRBNB/EPOXY Open source library for building complex screens in a RecyclerView
56. @heylaurakelly class ReservationEpoxyController : TypedAirEpoxyController<Reservation>() { ... private fun RowDataModel.buildModel() { when (this) { is LinkRowDataModel -> buildModel() is MapRowDataModel -> buildModel() is TitleRowDataModel -> buildModel() is HostAvatarRowDataModel -> buildModel() } } } 4. Configure UI Models with Epoxy
57. @heylaurakelly class ReservationEpoxyController : TypedAirEpoxyController<Reservation>() { ... private fun LinkRowDataModel.buildModel() = basicRow { id(this@buildModel.id()) title(title()) onClickListener(navigationContoller.navigateToDeeplink(app_url())) } } 4) Configure UI Models with Epoxy
58. JSON ArrayList<Row> rows( ) LinkRow MapRow TitleRow HostAvatarRow 1. JSON from server 2. Parse network response 3. Parse row subtypes 4. Configure UI models 5. Render components ReservationController ReservationFragment @heylaurakelly
59. {
 "type": "place",
 "id": "123",
 "rows": [ {
 "type": "row:carousel",
 "image_urls": [ "sightglassImage.png” ]
 },
 {
 "type": “row:title“,
 "title": "Sightglass Coffee",
 "starts_at": “Sun, Sept 24, 7:00 PM"
 },
 {
 "type": "row:action",
 "actions": [ /* ... actions here */ ]
 },
 {
 "type": "row:map",
 "address": "1234 Main Street"
 }
 ]
 } @heylaurakelly
60. How we’re using server-driven systems across Airbnb @heylaurakelly
61. @heylaurakelly
62. Building forms is simple, right? @heylaurakelly
63. What’s so hard about building a user flow? @heylaurakelly
64. What’s so hard about building a user flow? @heylaurakelly
65. What’s so hard about building a user flow? @heylaurakelly
66. What’s so hard about building a user flow? @heylaurakelly
67. @heylaurakelly Client-side logic
68. Wall-E JSON Payload Components Ordered list of screens Includes conditions for validation Questions Includes conditions for validation Answers Can be pre- populated, previously answered, or empty @heylaurakelly
69. Hide and show steps based on state @heylaurakelly
70. Lona Dynamic UI @heylaurakelly
71. • A unified format for describing views • Can be used standalone to natively parse and render pages • Can also underlie existing server-driven systems Lona Dynamic UI @heylaurakelly
72. Think you want to try it? @heylaurakelly
73. • API design is key • Think about platform differences early on • Know how server-driven you want to go Tips for building a server-driven system @heylaurakelly
74. @heylaurakelly
75. Thanks @heylaurakelly Reservations contributors Laura Kelly, Eric Horacek, Tyler Hedrick, Jenn Tilton, Callie Callaway, Laura Xu, Andy Bartholomew Wall-E contributors Truman Cranor, Kevin Almanza, Garrett Berg, Josh Freeman, Steven Liu, Chris Talley, Noah Hendrix Lona Dynamic UI contributors Nathanael Silverman, Kieraj Mumick, Devin Abott, Gabe G'Sell