Project Name
java-stellar-sdk
Describe your project in one sentence
The Java Stellar SDK provides APIs to build transactions, query Horizon, and interact with Soroban RPC, with Android support and implementations of several Stellar Ecosystem Proposals.
PG intake form
soft-launch
When was your project first released?
November 2015
Project Category
SDKs
Project Description
The Java Stellar SDK is a Java library for building Stellar applications on server-side JVM runtimes and Android. It provides transaction building, Horizon API access, Soroban RPC support, high-level Soroban smart contract support, and implements several Stellar Ecosystem Proposals. The SDK is listed on the official Stellar developer documentation and is used by projects including Lobstr Vault, Stellar Anchor Platform, and others.
Website
https://github.com/lightsail-network/java-stellar-sdk
Public Git Repository
https://github.com/lightsail-network/java-stellar-sdk
Describe your team members and your team's experience with the Stellar ecosystem
overcat (GitHub: overcat, Discord: @overcat.me) has been active in the Stellar community since 2018 and has rich experience in Stellar-related development, maintaining a series of Stellar infrastructure software. Currently maintained Stellar-related projects are listed at https://lightsail.network.
What's your project's retroactive impact over the last three months?
In Q1 2026, all planned deliverables were completed. The SDK shipped 3 releases (2.2.1 through 2.2.3), including a dedicated security hardening release (2.2.2) addressing XDR decoding vulnerabilities and Federation client DoS vectors. The XDR code generator was migrated from xdrgen into the SDK and substantially refactored. SEP-51 (XDR-JSON) support was implemented and validated against the Rust Stellar CLI. ScMap key ordering was fixed to automatically follow Soroban runtime rules.
Please list your deliverables of the last three months including proof of completion.
1. Ongoing SDK Maintenance
Description from last quarter:
This deliverable covers all necessary improvements to ensure the SDK's long-term viability. It includes resolving defects, implementing new features, refining code quality, and increasing test coverage to guarantee the SDK remains a robust and dependable tool for developers.
Proof of completion:
Three releases shipped. Release 2.2.2 was a dedicated security hardening release: a comprehensive audit was applied across the codebase, fixing XDR decoding vulnerabilities, Federation client DoS vectors, and multiple input validation and thread-safety issues.
2. Add Support for SEP-51
Description from last quarter:
Add support for SEP-51, enabling developers to serialize XDR data into JSON. This simplifies integration with web services and tooling, improves developer experience, and promotes consistent behavior across applications in the Stellar ecosystem.
Proof of completion:
SEP-51 support was added to the XDR generator, so all generated XDR types automatically gain toJson() / fromJson() methods. Output was cross-validated against the Rust Stellar CLI as a reference implementation.
3. xdrgen Migration and Refactoring
Description from last quarter:
Migrate xdrgen into a dedicated repository and perform necessary refactoring to improve maintainability and long-term sustainability of the SDK's tooling. This will strengthen the build pipeline and make future protocol upgrades easier to support. ref: https://github.com/orgs/stellar/discussions/1738
Proof of completion:
The XDR code generator was migrated from the external xdrgen tool into the SDK repository and substantially refactored, giving full control over the generated Java code. Snapshot tests were added to CI so any unintended output changes are caught automatically on future regeneration runs. During the refactoring, several latent security issues in the generated XDR encoding/decoding code were identified and fixed.
4. Improve the scval Build Feature
Description from last quarter:
Currently, when building a map, we require users to manually sort the keys. Enhance the scval build functionality to automatically sort the keys of the map, thereby simplifying the developer experience and reducing potential sources of errors.
Proof of completion:
Scv.toMap now automatically sorts map entries by key, matching the Soroban runtime's requirement that ScMap keys be in ascending order. The previous toMap(LinkedHashMap<SCVal, SCVal>) overload is deprecated. This eliminates a class of transaction failures that occurred when users provided unsorted maps.
What's are your project's goals for impact for the upcoming three months?
The primary goals for Q2 2026 are: achieve full Protocol 26 compatibility; implement SEP-46, SEP-47, and SEP-48 to improve Soroban smart contract tooling interoperability; and publish an AI coding agent skill to help developers build on Stellar more effectively. Ongoing maintenance will continue: responding to community issues and pull requests, keeping dependencies and CI/CD pipelines current.
Please list the deliverables you aim to create in the next three months and explain their ecosystem value.
1. Continuous Maintenance and Improvement
Regular SDK updates addressing Horizon, Soroban RPC, and protocol changes (including Protocol 26), bug fixes, feature requests, and documentation updates. Keep CI/CD pipelines and dependency updates current.
Proof: Release notes on GitHub, updated CHANGELOG, passing CI on master.
2. SEP-46, SEP-47, and SEP-48 Support
Add support for SEP-46 (Contract Meta), SEP-47 (Contract Interface Discovery), and SEP-48 (Contract Interface Specification). These three SEPs form the foundation for smart contract self-description: SEP-46 defines how contracts embed metadata in Wasm custom sections, SEP-47 lets contracts declare which SEPs they implement, and SEP-48 provides a rich interface specification including Soroban host types, user-defined types, and event schemas. Together they enable the SDK to parse and expose contract metadata, which is essential for tooling, auto-generated contract clients, and off-chain systems that need to understand contract interfaces.
Proof: Release on GitHub, PRs with implementation and tests, documentation.
3. AI Coding Agent Skill
Publish an AI coding agent skill for the java-stellar-sdk following the agentskills.io open standard, compatible with Claude Code, Codex CLI, Cursor, Gemini CLI, and others. The skill provides token-efficient documentation and best practices for AI-assisted development with the SDK, lowering the barrier for developers using AI tools to build on Stellar.
Proof: Skill available in the SDK repository, compatible with Claude Code, Codex CLI, Cursor, Gemini CLI, and others.
Budget Requested
15000
Legal Acknowledgements
Project Name
java-stellar-sdk
Describe your project in one sentence
The Java Stellar SDK provides APIs to build transactions, query Horizon, and interact with Soroban RPC, with Android support and implementations of several Stellar Ecosystem Proposals.
PG intake form
soft-launch
When was your project first released?
November 2015
Project Category
SDKs
Project Description
The Java Stellar SDK is a Java library for building Stellar applications on server-side JVM runtimes and Android. It provides transaction building, Horizon API access, Soroban RPC support, high-level Soroban smart contract support, and implements several Stellar Ecosystem Proposals. The SDK is listed on the official Stellar developer documentation and is used by projects including Lobstr Vault, Stellar Anchor Platform, and others.
Website
https://github.com/lightsail-network/java-stellar-sdk
Public Git Repository
https://github.com/lightsail-network/java-stellar-sdk
Describe your team members and your team's experience with the Stellar ecosystem
overcat (GitHub: overcat, Discord: @overcat.me) has been active in the Stellar community since 2018 and has rich experience in Stellar-related development, maintaining a series of Stellar infrastructure software. Currently maintained Stellar-related projects are listed at https://lightsail.network.
What's your project's retroactive impact over the last three months?
In Q1 2026, all planned deliverables were completed. The SDK shipped 3 releases (2.2.1 through 2.2.3), including a dedicated security hardening release (2.2.2) addressing XDR decoding vulnerabilities and Federation client DoS vectors. The XDR code generator was migrated from
xdrgeninto the SDK and substantially refactored. SEP-51 (XDR-JSON) support was implemented and validated against the Rust Stellar CLI.ScMapkey ordering was fixed to automatically follow Soroban runtime rules.Please list your deliverables of the last three months including proof of completion.
1. Ongoing SDK Maintenance
Description from last quarter:
Proof of completion:
Three releases shipped. Release 2.2.2 was a dedicated security hardening release: a comprehensive audit was applied across the codebase, fixing XDR decoding vulnerabilities, Federation client DoS vectors, and multiple input validation and thread-safety issues.
2. Add Support for SEP-51
Description from last quarter:
Proof of completion:
SEP-51 support was added to the XDR generator, so all generated XDR types automatically gain
toJson()/fromJson()methods. Output was cross-validated against the Rust Stellar CLI as a reference implementation.3. xdrgen Migration and Refactoring
Description from last quarter:
Proof of completion:
The XDR code generator was migrated from the external
xdrgentool into the SDK repository and substantially refactored, giving full control over the generated Java code. Snapshot tests were added to CI so any unintended output changes are caught automatically on future regeneration runs. During the refactoring, several latent security issues in the generated XDR encoding/decoding code were identified and fixed.4. Improve the scval Build Feature
Description from last quarter:
Proof of completion:
Scv.toMapfollowing Soroban runtime ordering lightsail-network/java-stellar-sdk#766 — Sort ScMap entries by key in Scv.toMap per Soroban runtime ordering rulesScv.toMapnow automatically sorts map entries by key, matching the Soroban runtime's requirement thatScMapkeys be in ascending order. The previoustoMap(LinkedHashMap<SCVal, SCVal>)overload is deprecated. This eliminates a class of transaction failures that occurred when users provided unsorted maps.What's are your project's goals for impact for the upcoming three months?
The primary goals for Q2 2026 are: achieve full Protocol 26 compatibility; implement SEP-46, SEP-47, and SEP-48 to improve Soroban smart contract tooling interoperability; and publish an AI coding agent skill to help developers build on Stellar more effectively. Ongoing maintenance will continue: responding to community issues and pull requests, keeping dependencies and CI/CD pipelines current.
Please list the deliverables you aim to create in the next three months and explain their ecosystem value.
1. Continuous Maintenance and Improvement
Regular SDK updates addressing Horizon, Soroban RPC, and protocol changes (including Protocol 26), bug fixes, feature requests, and documentation updates. Keep CI/CD pipelines and dependency updates current.
Proof: Release notes on GitHub, updated CHANGELOG, passing CI on master.
2. SEP-46, SEP-47, and SEP-48 Support
Add support for SEP-46 (Contract Meta), SEP-47 (Contract Interface Discovery), and SEP-48 (Contract Interface Specification). These three SEPs form the foundation for smart contract self-description: SEP-46 defines how contracts embed metadata in Wasm custom sections, SEP-47 lets contracts declare which SEPs they implement, and SEP-48 provides a rich interface specification including Soroban host types, user-defined types, and event schemas. Together they enable the SDK to parse and expose contract metadata, which is essential for tooling, auto-generated contract clients, and off-chain systems that need to understand contract interfaces.
Proof: Release on GitHub, PRs with implementation and tests, documentation.
3. AI Coding Agent Skill
Publish an AI coding agent skill for the java-stellar-sdk following the agentskills.io open standard, compatible with Claude Code, Codex CLI, Cursor, Gemini CLI, and others. The skill provides token-efficient documentation and best practices for AI-assisted development with the SDK, lowering the barrier for developers using AI tools to build on Stellar.
Proof: Skill available in the SDK repository, compatible with Claude Code, Codex CLI, Cursor, Gemini CLI, and others.
Budget Requested
15000
Legal Acknowledgements