About the author

Raúl Hernández López / Raul Hernandez Lopez

Senior Software Engineer - Android at Twitter & Kotlin lover


I would like to introduce myself as a continuous learner apart from being an experienced Software Engineer (10+ Years Experience), specialised on the Android platform (8 YE) & the Kotlin language (5 YE).

Moreover, I am a public speaker when I get the chance for it, so far I’ve participated like an international speaker in different events like podcasts, meetups or conferences such as Droidcon: UK’17 & ‘19, Spain’19, EMEA & APAC’20; FOSDEM’21; GOTO Copenhagen’19; AndroidDevPodcast Jul’20 or #ChimichurriCode Jun’21 podcasts; Kotlin London Dec’20 & Jun’21, MADG Spain Nov’20 RockNDroid Vigo May’21 or Londroid April’17 meetups. I write some articles in Medium (linked from this blog too), typically not technical at the end of the year to summarize the past year and technical ones too.

I am from Valencia (Spain) originally, where we use to love paella and horchata, nowadays I am living, working (from home) in London (UK) but I’ve also lived/worked in Antwerp (Belgium) for almost 1 year and a half.

I do love travelling when I can, listening music metal/rock gigs, reading tech/no-tech books, hanging out with friends, a very cold beer or running sometime.

Work experience


Senior Software Engineer - Android at Twitter in EMEA timezone from July 2018

  • Currently collaborating for the Twitter Blue team. Jan’21 - Nowadays.
  • Previously collaborated for the Consumer Search Clients (CSC) team. Dec’19 - Jan’21.
  • Previously collaborated for the Live Events / Events Clients (EC) team. Apr’18 - Sep’18 & May’19 - Dec’19.
  • Previously collaborated for the Periscope / Go Live Together (Hydra) team. Oct’18 - Apr’19
  • Roles:
    • Project Tech Lead (PTL).
    • Mentor for members of my teams.
    • Tech debt & architectural optimisations (PTL / Tech design shepherd).
    • Engineer on call to fix issues (maintainer).
    • Luna shepherd (helping interview huddles to embrace good practices).
    • Kotlin community active member (Kotlin & QE Automation shepherd).
    • Speaker & Driver/Enabler for Internal/External tech events / talks / podcasts.
    • Active interviewer for hiring new candidates for:
      • All levels: SWE 1 to Sr SWE.
      • All surfaces / platforms: Android -> specific expertise interview or iOS & RWEB -> general technical interviews.


  • Senior Software Engineer - Android (contract) at Twitter in London (UK) - from April the 30th to July 2018. Collaborating for Live Events team.
  • Lead Android Developer / Chapter Android Lead at Touch Surgery in London (UK) June 2017 until April the 27th 2018
  • …more at the bottom section…

2021 Public speaking

2021 Public written technical articles

2020 Public speaking

  • “Fueled Reactive apps with Asynchronous Flow & StateFlow to Sync with the UI” at Droidcon APAC (Dec).
  • “Fueled Reactive apps with Asynchronous Flow & StateFlow to Sync with the UI” at Kotlin London User Group (KUG) meetup (Dec).
  • “Fueled Reactive apps with Asynchronous Flow & StateFlow to Sync with the UI” at Kotlin Munich User Group (KUG) meetup (Nov).
  • “Fueled Reactive apps with Asynchronous Flow & StateFlow to Sync with the UI” at Madrid Android Developer Group (MADG) meetup (Nov).
  • “Fueled Reactive apps with Asynchronous Flow (& StateFlow to Sync with the UI)” at Droidcon EMEA (Oct).
    • Featured at Kotlin #221 Weekly
    • v2 explains in detail a full migration from RxJava 2 to Kotlin Coroutines & Flows / StateFlow / Channels.
    • Video
    • Slides
    • v2 Basics section was reduced going to the key points only in order to include a new section migrating Clean Architecture Callbacks on behalf of Kotlin StateFlow for Synchronous communication with the UI.
  • “Fueled Reactive apps with Asynchronous Flow” interview at AndroidDevPodcast with David Hackro (Jul)
    • Podcast audio interview (in Spanish)
    • We discussed step by step, talking about keypoints and reasoning behind why we would like to migrate a well-assembled Android app with a pre-existing foundation using RxJava 2 to use Kotlin Flow and friends instead.
  • “Fueled Reactive apps with Asynchronous Flow” v1 at Android Makers (Paris, France) - Virtual Android Makers edition (Apr).
    • v1 explains in detail a full migration from RxJava 2 to Kotlin Coroutines & Flows / Channels.
    • Video
    • Slides
    • v1 includes a longer Basics section as well as Asynchronous communication section. Migration for Clean Architecture and View Delegates to Kotlin Flow & Channels with Coroutines. Callbacks still pass results from the Use Cases / Interactors.
  • “Qué necesita un desarrollador para alcanzar sus metas?” interview at DevExperto’s “I stay at home” series with Antonio Leiva (Mar).

2020 Public written technical articles

2019 Public speaking

  • “Pushing Dynamic Features Your Users Want, As Quick As They Want Them”.

2018 Public written technical article

2017 Public speaking

  • “Building a Minimum Viable Product (MVP) with Face recognition and AR” at Droidcon UK (London) in October.
  • Light talk “Quest of a Hero” at Londroid April.
  • Light talk “From junior to experienced in few years” at Freakend Mobile in February.

Public code snippets & side projects


  • MSc Computational & Software Techniques in Engineering specialisation of Software Engineering at Cranfield University (UK)
  • Engineer in Computer Science specialisation of Software Engineering (second cycle) & Information Systems (first cycle) or BSc(Hons) Information Systems + MSc Software Engineering (BSc + MSc is equivalent to the Spanish Engineer degree) at Polytechnic University of Valencia (Spain)
  • BSc(Hons) Information technology at Edinburgh Napier University (UK)


I do enjoy meeting new cultures, learning from others & self-learning myself, listening rock / metal music, running, reading or travelling.

Extension of Formerly work experience

  • Senior Android Developer at Supe app / Rise Project UK London (UK) 2016-2017
  • Android developer at YouView in London (UK) 2015-2016
  • Senior Android Developer working at a startup called Critizen app / Next Chance Stocks SL in Madrid (Spain) 2015
  • Android Developer and Team Lead (contract) at a mobile little agency called Mobilendo in Valencia (Spain) 2014-2015
  • Software Development Engineer - C++ (contract) at the Mid-back office for Amadeus (on behalf of Harvey Nash) in Antwerp (Belgium) 2013-2014
  • Junior Software developer at Openbet in London (UK) 2012-2013
  • Junior Researcher and Android Software Engineer at Cranfield University (Erasmus internship) in Cranfield (UK) 2012
  • Technical Engineer In Administrative Data Processing at Common Council of Valencia (contract / internship granted for <30 recently graduates) in Valencia (Spain) 2010-2011
  • Junior Software engineer - PHP at a “bioinformatics startup” called Biotechvana in Valencia (Spain) 2010
  • IT Support and Development staff (contract) at Servipoli - Polytecnic University of Valencia (uni students job granted) in Valencia (Spain) 2008-2009
  • IT Support Staff at Valencian Institute of Statistics and applied sciencies (internship granted) in Valencia (Spain) 2007-2008

Contact me

Other public profiles