Paul Daniels
Principal Software Engineer at LeadIQ
Singapore
Summary
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Rockstar🎓
Top SchoolPaul Daniels is a Principal Software Engineer based in Singapore with 13 years of experience building resilient, high-throughput systems and improving developer experience across the full stack. He’s a Scala and ZIO specialist who led LeadIQ’s migration from REST to GraphQL and architected a uniform authentication and authorization platform used company-wide. An early engineering hire who helped scale the company through multiple funding rounds, he blends pragmatic API and microservice design with functional and reactive programming practices. Paul is an active open-source contributor—his work spans ZIO, Caliban (Scala GraphQL), and historical contributions to RxJS and AndroidAsync—often focusing on error handling, performance and tooling that surface subtle runtime guarantees. He’s also the author of "RxJS in Action," a detail that signals deep roots in reactive systems despite his current Scala focus. Colleagues describe him as someone who pairs hands-on coding with platform-level thinking to reduce vulnerabilities and lift team productivity.
12 years of coding experience
9 years of employment as a software developer
Bachelor of Science in Engineering (B.S.E.) Computer Science Engineering, Bachelor of Science in Engineering (B.S.E.) Computer Science Engineering at University of Michigan
German
Stackoverflow
18,513reputation
1.1mreached
322answers
1question
angular
top-1%
typescript
top-5%
observable
top-1%
firebase-realtime-database
top-5%
reactive-programming
top-1%
javascript
top-1%
Github Skills (38)
asynchronous10
unit-testing10
javascript10
async10
zio10
websocket10
rxjs10
wpgraphql10
java10
scala10
stream10
effects10
javas10
websockets-client10
backpressure10
Programming languages (11)
Github contributions (5)
ghostdogpr/caliban
Jan 2020 - Jun 2022
Functional GraphQL library for Scala
Role in this project:
Back-end Developer
Back-end DeveloperContributions:254 reviews, 34 commits, 97 PRs in 2 years 5 months
Contributions summary:Paul primarily focused on bug fixes and enhancements related to error handling and code encoding within the Caliban library. They addressed issues in the core functionality, ensuring correct error message encoding. The user also added source location mapping capabilities to the parsing component and implemented features to support directive processing, including the addition of apollo caching.
graphql-clientfunctional-programminggraphql-librarygraphql-serverscala
zio/zio
Mar 2020 - Oct 2022
ZIO — A type-safe, composable library for async and concurrent programming in Scala
Role in this project:Back-end Developer
Back-end DeveloperContributions:16 reviews, 24 commits, 27 PRs in 2 years 7 months
Contributions summary:Paul primarily contributed to the ZIO library by implementing new operators and enhancing existing ones. They introduced option combinators for `Managed` and added a new `fromOptionError` operator within the `ZIO` context, improving error handling capabilities. The user also implemented `scheduleWith`, `mapError`, `mapErrorCause`, `mapAccumM`, and `scanReduceM` operators within `ZStream`, expanding the library's functionalities for stream processing. The user further refactored existing code by reimplementing run* methods in terms of ZSink, and implemented ZSink.timed which added time tracking.
functional-programmingqueuesstreamsasynchronicityasync
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