Copyright 2008 Twilio

Empower Web Developers
To build Voice Communication
Apps that Make or Receive
Phone Calls, using only Basic
Web Development skills

Simple API
Only Five Building Blocks.
Powerful API
Build Advanced, Useful Applications
Pay-As-You-Go Pricing
No upfront, no commitment. Pay only for what
you use.

Voice Communications
(we use every day)
Sales Automation
Order Inquiry
Customer Relations Management
Intelligent Call Distribution
Emergency Notification
Appointment Reminders
Voicemail
Typically Costly and Difficult to Build

Costly to Build
Telecom
Engineers Tiny Workforce
Specialized Skill Set
Only Thousands of Qualified People
Voice Applications (Cisco Certified, etc.)
2
$20B Market 1 Complex Open Source Options
Steep Learning Curve

Commoditize the Skills
Telecom
Engineers
(thousands)
Voice
Communications Web Developers
Largest engineering workforce!
$20B Market
Millions of Skilled Workers
Processes
Agile Development
Commodity Hosting
Existing Infrastructure Investment
Twilio

Telecom Goo HTTP
XML
MP3, wav, etc.
Twilio
HARD EASY!

Simple API
<Say>
<Play>
<Say>Thank you for calling XYZ Corp.</Say>
<Play>http://mycompany.com/greeting.mp3</Play>
<Record>
<Record action=’http://mycompany.com/handler.php’/>
<Gather>
<Gather numDigits=’1’ action=’http://mycompany.com/handler.php’ />
<Dial>
<Dial>415-867-5309</Dial>
Just 5 Building Blocks

Example:
Example:
Example:

Next Grand Central
In 15 Lines of PHP!

Pay-As-You-Go Pricing
3¢ / minute
5¢ / minute toll free
$5 / month per phone number
No Contract, No Shenanigans
Free Trial with 1000 Minutes
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Twilio + AWS
S3
Storage of Voice Recordings
SQS
Decouples Telecom Infrastructure from Billing
EC2
Lots of CPU Intensive Services
Handle 9-5 Peaks, Minimize Costs Off-Peak
Pass Savings on to Customers!
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Twilio + AWS
HTTP VoIP
Load Balancer Load Balancer
Web Web API API VoIP VoIP
Load Balancer Load Balancer Load Balancer Load Balancer Load Balancer Load Balancer
Database Database Database
EC2
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Twilio + AWS
Realtime Transcoding
<Play>http://myserver.com/foo.mp3</Play>
256kbps stereo MP3 ➜ 11khz 8bit mono ulaw
<Record/>
http://api.twilio.com/..../Recordings/RE12345
http://api.twilio.com/..../Recordings/RE12345.mp3
11khz 8bit mono wav ➜ MP3
EC2
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Twilio + AWS
HTTP VoIP
Load Balancer Load Balancer
Web Web API API VoIP VoIP
Load Balancer Load Balancer Load Balancer Load Balancer Load Balancer Load Balancer
Database Database Database Media Layer Media Layer
EC2
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Twilio + AWS
Cent5
3rd Party Software for All Machines
(Apache, MySql, HaProxy, etc.)
Automated Build Process
(out of SVN)
Rev’d Infrequently
(Every couple months or so)
AMI
EC2
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Twilio + AWS
At Boot Time, Pulls Twilio Code from SVN
(What Code to Pull?)
SVN
AMI
EC2
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Twilio + AWS
Realms:
At Boot Time, Pulls Twilio Code from SVN
Dev, Stage, Prod
(What Code Accounts
Separate AWS to Pull?)
Completely Firewalled Off
Credentials Access Controlled
SVN
AMI
EC2
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Twilio + AWS
SVN Externals
Each Realm has a “rootfs” in SVN
Is overlaid on the AMI filesystem @ boottime
svnroot/realm-config/dev/rootfs
svnroot/realm-config/stage/rootfs
svnroot/realm-config/prod/rootfs
Each “rootfs” has SVN Externals
Point to various Twilio code-bases @REV
Bump versions independently in each realm
Bump different code bases independently
svnroot/realm-config/dev/rootfs:
svnroot/some-codebase ➜ ./usr/local/some-codebase @HEAD
svnroot/come-config-files ➜ ./etc/some-config-files @HEAD
svnroot/realm-config/prod/rootfs:
svnroot/some-codebase ➜ ./usr/local/some-codebase @12345
svnroot/come-config-files ➜ ./etc/some-config-files @12000
(Could also use branching / tagging just as easily.)
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Twilio + AWS
At Boot Time, Pulls Twilio Code from SVN
(What Code to Pull?)
svn export realm-config/$MYREALM/rootfs
Pulls all code targeted at this realm, dropped correctly in the filesystem!
SVN
AMI
EC2
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Twilio + AWS
Launches and Destroys Instances
Coordinates Load Balancers
UI + Pubsub + REST
BOXCONFIG
SVN
AMI
EC2
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Twilio + AWS
Each Instance Serves One Or More “Roles”
Purpose of the Instance
(VoIP, web, API, transcoding, etc.)
Set of Init scripts
EC2 Security Group
Nagios Settings
At Boot, Boxconfig:
Starts Correct Services
Notifies All Load Balancers
Updates Nagios
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Twilio + AWS Machine Startup/Shutdown
Boxconfig 1. Launch Instances
System 3 PUBSUB
2. Configure Services per Role
3 3. Notify Interested Load Balancers
1
HTTP VoIP
Load Balancer Load Balancer
Web Web API API VoIP VoIP
Load Balancer Load Balancer Load Balancer
3 Load Balancer Load Balancer
3 Load Balancer
Database Database Database Media Layer Media Layer Media Laye
2
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EC2 Learnings
Test “Roles” on Instance Sizes
Find optimal cost / performance tradeoff
Great for Load Testing
Spin up a test cluster, fire traffic, spin down...
Total cost: $5-10!
Great for Failure Testing
Hrm, what happens if I shoot this database...
terminateInstances()
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Jeff Lawson
jeff@twilio.com
http://www.twilio.com
Twitter: @twilio
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