Devices play a major role today and demand of device APIs is compelling. Many aspects such as standards, functional, non-functional, presentation, performance need to be considered when designing APIs for devices and this session will try to address them.

1. Kaminda Dimunge | SENIOR STAFF ENGINEER
ZEBRA TECHNOLOGIES LANKA (PVT) LTD
API Design Concepts for
Device Programming

2. Agenda
• Overview
• API Types
• Qualities of API
• Configuration Models
• Architecture
• Design Considerations
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4. Analogy of API design
Every car has a steering wheel, brake
pedals, and an accelerator. You might
find that hazard lights, the trunk release,
or radio are slightly different, but it’s rare
that an experienced driver can’t figure
out how to drive a rental car.
-The authors of APIs: A Strategy Guide (Daniel Jacobson, Greg
Brail, Dan Woods)
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5. What is an API?
In computer programming, an
application programming interface
(API) is a set of routines, protocols,
and tools for building software
applications. …
-Wikipedia
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6. Device Types
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Mobile Devices
Control Systems
Home Appliances
Public Safety
Healthcare Devices
Wearable Devices
Automotive Computers

7. Consider…
• Contains a display or not
• Limited memory and processing power
• Input output
• Stand-alone or connected
• Communication secured or not
• Security, safety compliances required
• …
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8. What can API do with devices?
• Get something done – Read a barcode
• Listen or monitor – Oil temperature of engine
• Watch – Is my dog eating the couch?
• Configure – Room temperature
• …
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9. API Types
• Classic API – Common local APIs
• Design Time Controls – Like Button control
• Web APIs – Browser plug-ins etc.
• Provisioning and Staging APIs – for mass
deployment, device profiling, licensing
• Software Wedge – Zero programming
• …
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10. Internet of Things (IOT)

11. Qualities of API
• Learnability-Easy to learn, self descriptive, help, developer
guide, wizards, IDE support, add-ons, plug-ins, intellisense,
samples
• Usability-Key classes, patterns
• Robustness-Boundary checks, Type verification
• Performance-Actions within duration, memory, processor
• …
• Eventually DX, UX
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12. Design Patterns
-Head First Design Patterns By Eric Freeman, Elisabeth Freeman, Bert Bates, Kathy Sierra
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13. Configuration Models
Applications
Device
Device
Applications
Host
Connectivity
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14. Standards
• Unified POS-OLE POS, Java POS, POS for .NET
• Web Services POS-WS-POS
• MagStripe Track Decoding-Master Card, Amex,
Loyalty Card
• Barcode Label Types-Dutch Postal, PDF 417, UPC
• NFC, SmartCard, Payment etc.-NFC Type1, NFC
Type 2, Memory Cards, CMU/MPU Cards
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15. API Architecture
Connectivity
API Layer
Application
Device
Architecture 1
Service Layer
API Layer
Application
Device
Architecture 2
Application
Host
API Layer
Device
Architecture 1
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16. Tunnelling, Active and Passive
Application 1
Application 3
Application 2 Host
Scanner 1
Scanner 2
Scanner 3
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17. API Security
• Does your API only do what is intended?
• Is it accepting only the data as designed?
• Do you have any hidden APIs for internal
with root access?
• Encryption and authentication adequate?
• …
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18. Concurrency
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19. Synchronous vs. Asynchronous
• Limitations on synchronization
• Avoid misuse
• Mitigate delay and block
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20. API Compatibility
• Application development contracted to
outside companies
• Changes are costly
– Positive test, Negative test, Stress test, Etc.
– Deploy into thousands of devices in many
geographically different locations
– User training
• Backward compatibility and forward
compatibility
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21. Compatibility
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22. Thank You