Uploaded September 2025 | Updated September 2026, 1 day ago
OTA updates promise instant delivery of new features, but the reality at scale is far more complex.
At React Universe Conf 2025, Adam Mruk (Senior Engineer at Klarna) takes us behind the scenes of building an in-house OTA solution serving 100M+ users across iOS, Android, web, and browser extensions. Drawing on Klarna’s experience, he reveals why “just pushing a new bundle” is only the beginning.
Skip the intro ⏩ 0:39
🔹 Why OTA can only ship JavaScript updates, not native code
🔹 Klarna’s custom OTA architecture: backend services, artifact storage, and client rollout control
🔹 Using Re.Pack for code splitting and Script Manager for bundle loading
🔹 Diff-based updates to shrink payloads from tens of MBs to hundreds of KBs
🔹 Reliability techniques: health checks (“dead on arrival”), rollback strategies, checksum validation
🔹 Real-world pitfalls with Hermes bytecode diffs, asset resolution on iOS, and rollout percentages
🔹 Why “instant” updates aren’t truly instant and how analytics and monitoring must adapt
This talk cuts through the hype and shows what it really takes to implement robust OTA updates in React Native at scale.
See you at another React Universe Conf 🎟️ clstk.com/47FlETL
Follow React Universe Conf on X to stay up to date 🐦 https://x.com/reactuniverse_
Check out Callstack content 📚 clstk.com/3KnXV0x
OTA updates promise instant delivery of new features, but the reality at scale is far more complex.
At React Universe Conf 2025, Adam Mruk (Senior Engineer at Klarna) takes us behind the scenes of building an in-house OTA solution serving 100M+ users across iOS, Android, web, and browser extensions. Drawing on Klarna’s experience, he reveals why “just pushing a new bundle” is only the beginning.
Skip the intro ⏩ 0:39
🔹 Why OTA can only ship JavaScript updates, not native code
🔹 Klarna’s custom OTA architecture: backend services, artifact storage, and client rollout control
🔹 Using Re.Pack for code splitting and Script Manager for bundle loading
🔹 Diff-based updates to shrink payloads from tens of MBs to hundreds of KBs
🔹 Reliability techniques: health checks (“dead on arrival”), rollback strategies, checksum validation
🔹 Real-world pitfalls with Hermes bytecode diffs, asset resolution on iOS, and rollout percentages
🔹 Why “instant” updates aren’t truly instant and how analytics and monitoring must adapt
This talk cuts through the hype and shows what it really takes to implement robust OTA updates in React Native at scale.
See you at another React Universe Conf 🎟️ clstk.com/47FlETL
Follow React Universe Conf on X to stay up to date 🐦 https://x.com/reactuniverse_
Check out Callstack content 📚 clstk.com/3KnXV0x
