This document discusses Airbnb's migration from a monolithic Ruby on Rails application to a service-oriented architecture (SOA) with over 450 API endpoints. Some key points discussed include adopting SOA principles like single responsibility services, migrating core data and logic incrementally, implementing frameworks for documentation and observability, and cultural shifts within engineering teams to own services. The migration provided benefits like faster deployments, increased developer productivity, and improved performance, but required long-term commitment and standardization efforts.

1. Airbnb’sGreatMigration:
BuildingAPIsatScale
JESSICA TAI • 24 APRIL 2019 • API DAYS
SINGAPORE

2. @jessicamtai
2014

3. @jessicamtai
2015+

4. @jessicamtai
Hi,I’mJessica.
Ipairprogram
withmycorgi.

5. Agenda
1. Why migrate
2. Service design tenets
3. Decomposition
4. Best practices
5. Cultural shifts
6. Results
@jessicamtai

6. Monorail,ourRubyonRailsmonolith
@jessicamtai

7. Agenda
1. Whymigrate
2. Service design tenets
3. Decomposition
4. Best practices
5. Cultural shifts
6. Results
@jessicamtai

8. @jessicamtai

9. Howcanwescale
thegrowingteam?
@jessicamtai

10. Oursolution:Service-orientedarchitecture(SOA)
NETWORK OF LOOSELY-COUPLED SERVICES
@jessicamtai
Client
API Gateway
Service 1
Service 2 Service 3
Data store Data store

11. CheckoutpageinSOA
@jessicamtai
Homes service
Reservation service
Review service
Availability service
Messaging service
Business travel service
Cancellation service
Homes demand service
Pricing service
User
service
Checkout page service

12. Agenda
1. Why migrate
2. Servicedesigntenets
3. Decomposition
4. Best practices
5. Cultural shifts
6. Results
@jessicamtai

13. Servicesaddressaspecificconcern
@jessicamtai

14. Eachdatasourceaccessedby
oneread,onewriteAPI @jessicamtai

15. Scalefortomorrow
@jessicamtai

16. Buildforproduction
@jessicamtai

17. Agenda
1. Why migrate
2. Service design tenets
3. Decomposition
4. Best practices
5. Cultural shifts
6. Results
@jessicamtai

18. Requestlifecycle
Client traffic
Shared
database
Monorail
Data access query
Business logic
Presentation view
V1: MONORAIL
@jessicamtai

19. Requestlifecycle
Monorail
API traffic
Routing & view
Business logic, model, data
via services
Client traffic
V2: MONORAIL & SERVICES
@jessicamtai

20. MIDDLE TIER
Shared business logic
Servicetypes
STRICT FLOW OF DEPENDENCIES
PRESENTATION
Synthesize
DERIVED DATA
Shared context, multiple sources
DATA
Entity read and writes
@jessicamtai

21. MIDDLE TIER
Shared business logic
PRESENTATION
Synthesize
DERIVED DATA
Shared context, multiple sources
DATA
Entity read and writes
Servicetypes
STRICT FLOW OF DEPENDENCIES
@jessicamtai

22. MIDDLE TIER
Shared business logic
PRESENTATION
Synthesize
DERIVED DATA
Shared context, multiple sources
DATA
Entity read and writes
Servicetypes
STRICT FLOW OF DEPENDENCIES
@jessicamtai

23. MIDDLE TIER
Shared business logic
DERIVED DATA
Shared context, multiple sources
DATA
Entity read and writes
PRESENTATION
Synthesize
Servicetypes
STRICT FLOW OF DEPENDENCIES
@jessicamtai

24. PRESENTATION
Synthesize
MIDDLE TIER
Shared business logic
DERIVED DATA
Shared context, multiple sources
DATA
Entity read and writes
Servicetypes
STRICT FLOW OF DEPENDENCIES
@jessicamtai

25. Whattomigratefirst?
@jessicamtai

26. Homes
H O S T E D B Y K I T T Y · A P T O S , C A L I F O R N I A
Mushroom Dome
@jessicamtai

27. Homes data
service
Shared
database
Monorail
Data access query
Business logic
1.Migratingcoredatamodels
Presentation view
Homes
database
@jessicamtai

28. Homes data
service
Shared
database
Monorail
Data access query
Business logic
2.Migratingcorebusinesslogic
Presentation view
Homes
database
Pricing derived
data service
Pricing trends
data store
@jessicamtai

29. Homes data
service
Shared
database
Monorail
Data access query
Business logic
3.Migratingcoreproductviews
Presentation view
Homes
database
Pricing derived
data service
Pricing trends
data store
Checkout
presentation
service
@jessicamtai

30. Homes data
service
Shared
database
Monorail
Data access query
Business logic
4.Migratingcoreproductwrites
Presentation view
Homes
database
Homes
validation
middle-tier
Pricing derived
data service
Pricing trends
data store
Checkout
presentation
service
@jessicamtai

31. Requestlifecycle
Monorail
API traffic
Routing & view
Client traffic
V2: MONORAIL & SERVICES
@jessicamtai
Business logic, model, data
via services

32. Requestlifecycle
API gateway
Middleware
Session data
service
Authentication
data service
Oauth data
service
Risk derived
data service
...
Request
context
Presentation, logic, data
V3: SOA & API GATEWAY
Routing
@jessicamtai

33. Requestlifecycle
API gateway
Middleware
Session data
service
Authentication
data service
Oauth data
service
Risk derived
data service
...
Request
context
Web rendering
service
HTML viewV3: SOA & API GATEWAY
Routing
@jessicamtai
Presentation, logic, data

34. Monolith
world
Services
world
TheFutureTM
@jessicamtai

35. Migration
world
Monolith
world
Services
world
@jessicamtai

36. Agenda
1. Why migrate
2. Service design tenets
3. Decomposition
4. Bestpractices
5. Cultural shifts
6. Results
@jessicamtai

37. Frameworks
Auto-generate code
Documentation
Updated upon deployment
Observability
Templates
Standardizeservices&APIs
SCALE WITH CONSISTENCY
@jessicamtai

38. Migrationcomparisonframework
Monorail
Service
Database
Response A
Response B
Consumer +
offline
comparison
framework
Offline
queryable
metrics
@jessicamtai

39. ThriftIDL
API FRAMEWORK
/** Batch request for demo data */
struct LoadSomeDataRequest {
1: optional set<i64> ids
/** Some extra context baz */
2: optional bool fooBar (personal)
}
@jessicamtai

40. ThriftIDL
API FRAMEWORK
/** id to data response */
struct LoadSomeDataResponse {
1: optional map<i64, SomeData> data
}
@jessicamtai
/** Batch request for demo data */
struct LoadSomeDataRequest {
1: optional set<i64> ids
/** Some extra context baz */
2: optional bool fooBar (personal)
}

41. ThriftIDL
API FRAMEWORK
@jessicamtai
/** /loadSomeData batch endpoint */
LoadSomeDataResponse loadSomeData
(1: LoadSomeDataRequest request)
throws (1: SomeException exception1)(

42. ThriftIDL
API FRAMEWORK
@jessicamtai
accept_replay = "true",
rate_limit = “true",
/** /loadSomeData batch endpoint */
LoadSomeDataResponse loadSomeData
(1: LoadSomeDataRequest request)
throws (1: SomeException exception1)(

43. ThriftIDL
API FRAMEWORK
@jessicamtai
accept_replay = "true",
rate_limit = “true",
slo_error_budget_percent = “0.1”,
slo_success_rate = “99",
slo_success_rate_interval_minutes = "5",
)
/** /loadSomeData batch endpoint */
LoadSomeDataResponse loadSomeData
(1: LoadSomeDataRequest request)
throws (1: SomeException exception1)(

44. Thrift annotations
@jessicamtai

45. Block comments
from .thrift file
@jessicamtai

46. @jessicamtai

47. @jessicamtai

48. Agenda
1. Why migrate
2. Service design tenets
3. Decomposition
4. Best practices
5. Culturalshifts
6. Results
@jessicamtai

49. 2016:
One small infra team
Airbnb’s SOA progress
@jessicamtai

50. Productculture:
shipthingsquickly
@jessicamtai

51. Incrementalmigration
@jessicamtai

52. Orgchallenges:
servicebuildinginparallel
@jessicamtai

53. Product
Frontend
Monorail
Infrastructure
Backend
Monorail+services
Volunteer
sysops
on-call
@jessicamtai

54. @jessicamtai
Product
Frontend
Monorail
Infrastructure
Backend
Monorail+services
Volunteer
sysops
on-call

55. On-callrotationperteam
SERVICE OWNERSHIP
Checkout
service
Pricing service User service
Product Team Infrastructure Team
@jessicamtai

56. Agenda
1. Why migrate
2. Service design tenets
3. Decomposition
4. Best practices
5. Cultural shifts
6. Results
@jessicamtai

57. 2016:
One small infra team
2019:
Whole engineering org
Airbnb’s SOA progress
@jessicamtai

58. ! Faster build & deploy times
○ Hours (Monorail) to minutes (service)
○ Fewer reverts
! Quicker bug fixes
! Increased developer productivity happiness
Promisinginitialresults
SUCCESS
@jessicamtai

59. ! Lower latency from parallelization
○ Ruby monorail single-threaded
○ Java services multi-threaded
! Search results page 3x faster
! Homes description page 10x faster!
Latencyresults
SUCCESS
@jessicamtai

60. 500+ 67%
Deploys in MonorailEngineers
2016
@jessicamtai

61. 500+ 67%
Deploys in MonorailEngineers
1400+ 3.5%
2016
2019
@jessicamtai

62. Production traffic via API Gateway
45%
@jessicamtai

63. 450+ 2.4k+
API endpointsServices
IDL
@jessicamtai

64. ButisSOAbetter?
@jessicamtai
/findHomeListById
/fetchReservations
/loadReviewsForUser
/getAvailability
/createMessage
/setBusinessTravel
/getCancellations
/calculateHomeDemand
/fetchDates
/getUser
Checkout presentation service

65. HowcanweimproveourAPIs?
@jessicamtai

66. Home Pricing
Availability
Host&guest
users
Reservation
Checkout presentation service
@jessicamtai

67. Easyandquicktowrite
@jessicamtai

68. • Prepare for a long commitment
• Decompose incrementally
• Scale via standardization with frameworks, tools
• Shift development culture
SOAmigration
TAKEAWAYS
@jessicamtai

69. @JESSICAMTAI
LINKEDIN.COM/IN/JESSICATAI
API DAYS SINGAPORE 2019