Junior Software Developer jobs in United Kingdom

Captur helps software understand real world scenes in real-time with an SDK for flexible, on‑demand visual recognition. We’re a small, rapidly scaling team backed by top‑tier investors; we recently closed a $6M seed round to accelerate product and go‑to‑market growth. We are global leaders in edge ML and have validated +150M images on‑device for enterprise customers such as Lime. Next, expanding as a horizontal platform across use cases that require real‑time speed, high volume and coverage across a wide range of mobile devices.

You’ll own core pieces of our Android SDK: performance, stability and developer experience. You’ll profile power, latency and memory, optimise threading and networking, shape public Kotlin APIs and harden telemetry. You’ll also take ownership of production issues surfaced by Solutions Engineering and Customer Success: reproduce, fix the root cause and ship improvements. You won’t handle customer contracting or sales calls; your focus is a fast, stable SDK that makes integrations effortless.

In H1, you’ll be partnering with the Head of Mobile and our React Native SDK engineer to deliver the next‑generation SDK: translate product requirements into a revised SDK architecture, lead implementation of the key features, run a staged beta and show before→after gains on crash/ANR, latency and battery on our device matrix.

• Performance and reliability
• Profile and optimise on‑device performance and data paths (battery, CPU/GPU, memory)
• Own threading, scheduling and back‑pressure; make frame‑time and latency predictable across device classes
• Define and monitor SDK health metrics at scale (crashes, ANRs, error rates, perf envelopes)
• API design and developer experience
• Design clear, stable, Kotlin‑first public APIs (versioned, well‑documented, testable)
• Implement best practices for networking, auth and IO; make failure modes deterministic and observable
• Maintain Android sample apps and quickstarts
• Release & version management
• Own CI/CD for the Android SDK (GitHub Actions/GitLab CI) and dependency hygiene; prepare release artefacts and hand off to Solutions Engineering for release cadence and publishing
• Ship high‑quality migrations and deprecations with zero‑surprise changelogs
• Partner with the Solutions Engineer: reproduce field issues, write minimal repros, land fixes and verify via dashboards
• Provide concise developer‑facing change notes/migration snippets to the Solutions Engineer for release notes
• Roadmap contribution
• Co‑design the next generation of the Android Captur SDK for release at the end of Q2
• Champion performance budgets and device‑class targets during planning
• SDK Engineer owns: code quality, API design, perf, stability, instrumentation, and technical notes for releases
• Solutions Engineer owns: release cadence, artefact publishing, changelogs, customer comms and debug sessions

• 30 Days:
• Get fully set up, read the codebase and understand how the SDK integrates into customer apps (run the sample integrations end‑to‑end)
• Take on small backlog items and minor bug fixes to gain experience with the SDK
• Learn internal processes and our crash/health monitoring (Datadog); identify the top 2–3 crash/ANR fingerprints and how they’re currently triaged
• 60 Days:
• Own a set of feature requests/changes in the existing SDK from design to merge
• Improve crash reporting and metrics: add any missing telemetry/events needed for clearer root‑cause and cleaner dashboards
• Familiarise yourself with the existing release cycle and CI/CD process
• 90 Days:
• Provide meaningful input on core sections of the SDK revamp (review/author proposals
• Become the Android SDK SME day‑to‑day: work independently with the Solutions Engineer to reproduce issues and land fixes that improve customer experience
• Proactively spot and address stability/robustness gaps (tests, fallbacks, device‑specific edge cases) and keep the docs/changelogs tidy

Example Success Metrics: release stability and a visible reduction in SDK failure rate.

• Deep Kotlin (3+ years) experience focused on systems‑level/SDK work (not UI‑heavy app development): threading/concurrency, memory, camera/graphics/IO and performance tooling (Android Studio profilers, Perfetto, Systrace)
• Shipped code across hundreds of device models and over 1m monthly SDK sessions with proven strategies to handle device quirks
• Hands‑on experience with monitoring tools (Crashlytics/Sentry/Datadog or similar) and adding the right events to enable root‑cause analysis (crashes, ANRs, latency)
• Experience delivering SDKs via GitHub Actions/GitLab CI with Gradle/Maven, semantic versioning and signed artefacts, maintaining clean migrations and changelogs
• Utilise test‑driven development in practice – writing unit and instrumentation tests and standing up integration harnesses around threading/IO
• Networking/auth/API fundamentals tuned for mobile constraints
• Based in the UK (London preferred) and able to work from our London office at least 1 day per week on an ongoing basis

• Built or maintained Android SDKs used by external developers (versioning, migrations, deprecations)
• Familiarity with common Computer Vision pipelines and ML Ops basics for mobile development
• Practical experience integrating or optimising TFLite/LiteRT for real‑time use
• Able to work from our London office 3 days per week during the first 3 months to speed up pairing and knowledge transfer