Java Engineer Jobs

Staff/Senior Java Engineer, OKX Wallet (Web3) Who We Are OKX Wallet is OKX's self-custody wallet, built for users worldwide to securely and conveniently store, manage, and use their on-chain assets. The wallet backend operates in a multi-chain, multi-asset, high-concurrency environment shaped by on-chain state uncertainty and strict fund-security requirements — combining the complex-systems challenges of traditional internet backends with the transaction, signing, and on-chain interaction problems unique to blockchain. We're looking for a Senior Java Engineer with roughly 5–10 years of backend experience: someone with strong engineering fundamentals who can independently own core modules, exercise sound judgment on complex problems, and proactively coordinate across upstream and downstream teams to drive work to completion. What You'll Do Own core wallet backend modules. Build and continuously improve address management, asset synchronization, transaction construction, broadcasting, on-chain confirmation, gas estimation, nonce management, and transaction-state tracking. Understand each module's role in the full wallet flow, and keep stability, performance, and maintainability front of mind. For complex requirements, break the problem down before choosing an implementation rather than stacking code or reusing old designs. Build transaction and on-chain interaction scenarios. Work on transfers, token approvals, contract interactions, cross-chain, swaps, DApp connections, and signature-request handling. Understand a transaction's full lifecycle — from initiation through construction, signing, broadcasting, on-chain confirmation, and final state update — and diagnose issues like stuck transactions, duplicate submissions, state inconsistencies, and on-chain success that isn't reflected in the business system, using logs, on-chain data, and call traces. Support multi-chain and new-chain integration. We already support EVM, Tron, and Solana, and continuously onboard new pu

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is the Role We are on the lookout for a Senior Software Engineer to join our Elasticsearch team and focus on ensuring that the shared platform functionalities of Elasticsearch are easy to use, performant, maintainable, and secure. The team’s mission is to create foundational infrastructure and shared functionality that enables engineers to develop, extend, and support Elasticsearch. The team owns common functionality such as services, settings, and scripting, and makes Elasticsearch extensible through plugins or the Painless scripting language. The team also makes Elasticsearch observable by providing logging and telemetry information. We also own the orchestration of Elasticsearch in serverless, the CI/CD workflows, and enable Elasticsearch developers to deliver Elasticsearch to customers - serverless, cloud, and on-premise alike. You will be a strong individual contributor on the team, but you will also contribute to and lead cross-team projects. We need someone who has great design skills, who can work at a low level of abstraction but can equally drive and communicate technical concepts across a variety of collaborators. What You Will Be Doing Contributing to large, impactful projects that evolve the core infrastructure that underpins Elasticsearch. Making Elasticsearch developers more productive by identifying and developing opportuniti

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Principal Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your deep distributed systems expertise to design, build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully res

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Principal Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your deep distributed systems expertise to design, build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully res

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Principal Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your deep distributed systems expertise to design, build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully res

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Principal Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your deep distributed systems expertise to design, build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully res

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Principal Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your deep distributed systems expertise to design, build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully res

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Principal Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your deep distributed systems expertise to design, build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully res

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Principal Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your deep distributed systems expertise to design, build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully res

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Senior Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your distributed systems expertise to build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully resolved. What You Bring:

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Senior Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your distributed systems expertise to build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully resolved. What You Bring:

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Senior Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your distributed systems expertise to build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully resolved. What You Bring:

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Senior Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your distributed systems expertise to build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully resolved. What You Bring:

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Senior Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your distributed systems expertise to build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully resolved. What You Bring:

Elastic, the Search AI Company, enables everyone to find the answers they need in real time, using all their data, at scale — unleashing the potential of businesses and people. The Elastic Search AI Platform, used by more than 50% of the Fortune 500, brings together the precision of search and the intelligence of AI to enable everyone to accelerate the results that matter. By taking advantage of all structured and unstructured data — securing and protecting private information more effectively — Elastic’s complete, cloud-based solutions for search, security, and observability help organizations deliver on the promise of AI. What Is The Role: We are on the lookout for a Senior Software Engineer to join our Elasticsearch - Distributed Systems team and focus on how Elasticsearch provides scale, performance, and resilience, especially in the context of our Serverless offering. You will be tackling deep distributed systems challenges in how nodes in an Elasticsearch cluster communicate, and how data are indexed, allocated, and managed across nodes. What You Will Be Doing: Leveraging your distributed systems expertise to build, and operate core pieces of our next-generation Serverless Elasticsearch offering, directly impacting the experience of customers worldwide. Improving Elasticsearch’s components that support concurrent and consistent indexing across multiple machines. Maintaining our cluster coordination system to keep performance high even though nodes come and go from the cluster and data moves around, while maintaining the safety and liveness properties of the system as a whole. Pushing the limits on the number of shards, nodes, and petabytes that Elasticsearch can handle today. Looking into all kinds of issues, including performance or concurrency issues, and proposing solutions. Supporting our support engineers with the harder problems. Owning operational investigations end-to-end, until performance or stability issues are successfully resolved. What You Bring: