Android Engineer

About The Company
Qaelum builds verified commodity data for markets where reliable transaction records are limited. Our field agents record commodity trades at buying centres and landing sites, including cocoa and cashew transactions in Ghana and tuna activity in the Maldives, with Nigeria planned next. Lenders, buyers, and regulators depend on this information to make decisions, so each record must be trustworthy. It needs to demonstrate that it was created by a genuine device, at a particular place and time, and that its contents have not been altered.About The Role
We are seeking an experienced Android Engineer to build a native Kotlin capture application for Android 13 and later. Field agents will use the app in areas where connectivity may be limited, so it must be reliable, secure, and straightforward to use on mid-range devices. You will turn a detailed written specification into production-ready software, using published test vectors and a backend verification system to validate the app’s output. You will work directly with the CTO and founders in a remote, asynchronous, documentation-first environment.Qualifications
You have at least five years of professional Android development experience, primarily using Kotlin, and have shipped applications to production. You are comfortable implementing security-sensitive features and can demonstrate practical understanding of cryptographic signatures, hashing, DER encoding, and deterministic, byte-exact serialization. Hands-on experience with Android Keystore, key attestation, and Play Integrity is valuable;
alternatively, you can show that you learn unfamiliar technical domains quickly and carefully.
You have experience designing offline-first applications, handling background work, and protecting data in encrypted local storage. You test against written specifications and test vectors rather than relying only on manual checks or a successful run on one device. Clear written English is essential for technical documentation, asynchronous collaboration, and thorough pull request reviews.
Additional experience with iOS App Attest, CameraX, Android sensor APIs, low-end devices, or patchy networks in West Africa or South Asia is welcome. Background in blockchain, Bittensor, fintech, or supply-chain traceability may also be useful.Responsibilities
Build and maintain the native Kotlin application, including secure capture workflows for photographs and associated EXIF, GPS, and motion-sensor data. Implement non-exportable ECDSA P-256 device keys in Android Keystore, using StrongBox where available, and support key attestation and device enrolment. Develop a deterministic encoder that matches the canonical format byte for byte and verify its behavior against published test vectors.
Create signed capture statements that protect the integrity of captured information. Hash privacy-sensitive data on the device and ensure it is never uploaded in raw form. Implement offline capture sessions with an encrypted local queue that synchronizes when connectivity returns, enforcing the required sequence: a capture must be committed before it can be submitted. Build an onboarding capability check so agents can determine whether their device meets requirements. Ensure camera, location, and microphone permission handling complies with Google Play policies. Document design decisions, write appropriate tests, and participate in careful code reviews.Benefits
Work remotely with an asynchronous, documentation-first team and collaborate directly with the CTO and founders. You will have clear written specifications, recorded decisions, and a defined verification process to guide implementation. This role offers the opportunity to own a security-critical mobile product with a direct connection to real-world commodity markets and the people who rely on accurate transaction records.Equal Opportunity
Qaelum welcomes applicants from diverse backgrounds and evaluates candidates on their relevant skills, experience, and ability to contribute to the role.
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