Generalist Developer (Android, iOS & Golang) (x/f/m/d)

At zeitkapsl, we believe your photos should belong only to you. That's why we're building a privacy-first photo storage service that feels as effortless as Google Photos, but without the trade-off of giving your life away.

We've spent the past few years designing and building the technical foundation. The product is live, and people who care about privacy already use it. All our clients are open source, released under the GPLv3 license, and you can browse the code on Codeberg.

Curious what we're currently working on Our public roadmap shows the features and topics we're prioritizing.

• Generalist Developer (Android, iOS & Golang) (x/f/m/d)
• Internship: On-Device Natural Language Search in an E2EE Photo Library
• Internship: Digital Inheritance for End-to-end Encrypted Photo Backup Service
• Internship: Visual Similarity Check for End-to-end Encrypted Photo Backup Service
• Internship: End-to-end Encrypted OCR and Classification Label Analysis for Photos
• Internship: HDR Support for End-to-end Encrypted Photo Backup Service
  
  

Interested

Send a short message to [HIDDEN TEXT]

Tell us who you are, what motivates you, and how you'd help bring privacy to more people.

We don't care about fancy degrees or shiny CVs: shared values and motivation matter most.

Generalist Developer (Android, iOS & Golang) (x/f/m/d)

We're a small team, so we're hoping to find one person who can work across our client stack: Android, iOS, and the shared Golang core, rather than three separate specialists.

Requirements

• Permanent residency in Austria (we're not able to offer relocation or sponsor a visa)
• Experience with modern Android development
• Fluent Kotlin
• Jetpack Compose, Material Design, Koin, Koil, gradle
• Writing performant Compose code
• JNI / NDK
• Experience with modern iOS development
• Fluent Swift
• Swift UI, XCode
• Interoperability between Swift and C / Objective-C
• Writing performant Swift UI code
• Experience with software development in Go
• go std-lib, go toolchain, go modules and packages
• Writing robust and performant Go code
• cgo and interoperability with other programming languages
• Good knowledge of symmetric cryptography: AES-GCM, HKDF, PBKDF2, BCRYPT
• SQLite integrations, ideally using sqlc
• Open API / REST definitions, and HTTP
• We're aware this is a lot to ask across three platforms, but in a small team like ours, everyone touches everything, so it's genuinely what the role requires.
  

Responsibilities

• Performance optimizations
• Developing new features
• Creating automated tests
  
  

What We Offer

• Flexible working hours (part-time only, for now)
• Salary
• €43,100 gross / year (full-time equivalent) for entry-level positions
• €75,000 gross / year (full-time equivalent) for experts
• Work location: Vienna or Klagenfurt, home office, remote, whatever works best for you
• Klimaticket (Austria-wide public transport pass)
  

Internship: On-Device Natural Language Search in an E2EE Photo Library

zeitkapsl.eu is a European end-to-end encrypted alternative to Google Photos. All clients are open source and released under the GPLv3 license (Codeberg). A much requested feature by our customers is the ability to search their photo library using natural language rather than fixed labels. Currently, we are using image classification models to tag images with a fixed list of tags/categories. This should be extended by a natural language search feature. Due to the end-to-end encrypted nature of zeitkapsl, inference as well as the querying must happen on the users end devices.

Starting point for this project is a survey/review of the current state-of-art of multimodal embeddings (e.g. CLIP/MobileCLIP) as well as small multimodal language models which will make up the base for the search feature. Selected open models should be runnable in the ONNX Runtime.

Fields: security, ML/AI, IR

Internship: Digital Inheritance for End-to-end Encrypted Photo Backup Service zeitkapsl

zeitkapsl.eu is a European end-to-end encrypted alternative to Google Photos. All clients are open source and released under the GPLv3 license (Codeberg). Due to the end-to-end encrypted nature of zeitkapsl, conventional handling of digital inheritance by the service provider is not possible. To still achieve the possibility of digital inheritance, the cryptographic material has to be provided to the heirs in such a way that they can access the encrypted library upon death of the account owner without the service provider ever being able to access this material (e.g. leveraging Shamir Secret Sharing or a similar secret sharing technique).

The developed scheme needs to be implemented in the Web App (Svelte 5, webcrypto-API) in such a way that it is usable and understandable to users without knowledge about cryptography.

Fields: security, cryptography, usable security

Internship: Visual Similarity Check for End-to-end Encrypted Photo Backup Service zeitkapsl

zeitkapsl.eu is a European end-to-end encrypted alternative to Google Photos. All clients are open source and released under the GPLv3 license (Codeberg). A much requested feature by our customers is support for deduplicating visually similar images.

To achieve that, we need to scan images for perceptual visual features and cluster them based on similarity. The customer should then be able to select the best image from each cluster.

This needs to be implemented in the Web App (Svelte 5 + WASM), Android, and iOS. The mobile apps utilize a shared logic core written in Golang; the UI is written in native Jetpack Compose and SwiftUI.

Fields: security, ML/AI, visual computing

Internship: End-to-end Encrypted OCR and Classification Label Analysis for Photos

zeitkapsl.eu is a European end-to-end encrypted alternative to Google Photos. All clients are open source and released under the GPLv3 license (Codeberg). A much requested feature by our customers is the ability to search for text or concepts within images.

Currently, we utilize platform-native features on Android, which need to be replaced in order to be accepted into the F-Droid app store. They should be replaced by open models runnable in the ONNX Runtime.

Fields: security, ML/AI, visual computing

Internship: HDR Support for End-to-end Encrypted Photo Backup Service zeitkapsl

zeitkapsl.eu is a European end-to-end encrypted alternative to Google Photos. All clients are open source and released under the GPLv3 license (Codeberg). A much requested feature by our customers is support for HDR images.

The image processing pipeline should be extended to extract representations of HDR maps and make them previewable across platforms (iOS, Android, Web in browsers supporting HDR images) while still preserving the original format.

Fields: security, visual computing

If that sounds interesting, please apply via email: [HIDDEN TEXT]