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Keystone

open-source

Lightweight multi-architecture assembler framework supporting Arm, Arm64, x86, MIPSMIPSA RISC processor architecture originally developed at Stanford and commercialized by MIPS Technologies, widely used in embedded and network devices; cyber tools target it to analyze or exploit routers, cameras, and similar hardware., RISC-V, and more with a C/C++ API and multi-language bindings.

Summary

Keystone is an open-source assembler framework, dual-licensed under GPLv2 for open-source use with a separate commercial license required for production deployment, and it works as a library that developers link into their own code rather than a standalone application, with bindings for Python, Go, Rust, Ruby, C#, and several other languages. It targets people building tools that generate machine code on the fly, such as reverse engineers and exploit developers writing shellcode, and it covers a wide range of architectures including x86, Arm, Arm64, MIPS, PowerPC, RISC-V, and Sparc. It is built on LLVM but extends it, positioning itself against hand-rolled or architecture-specific assemblers rather than any single named competitor. First committed in 2016 with 81 contributors and six tracked releases, it has seen only one commit in the past year, so it should be treated as stable but largely dormant.

Lightweight multi-architecture assembler framework supporting Arm, Arm64, x86, MIPS, RISC-V, and more with a C/C++ API and multi-language bindings.

How Keystone helps

How do I turn a handful of assembly instructions into raw bytes I can inject into a process?

takes the assembly text and the chosen architecture and returns the encoded machine code as a byte buffer, ready to write into memory or a file

Which instruction set do I target when my shellcode has to run on an unfamiliar architecture?

covers Arm, Arm64, MIPS, PowerPC, RISC-V, Sparc and x86 among others, so the same encoding workflow carries over to whichever processor the target actually runs

Can I generate code for one architecture from a codebase written in a language other than C?

exposes the same encoding calls through bindings for Python, Go, Rust, Ruby, C# and several other languages, so the assembler is reachable from whatever the surrounding tool is written in

Am I free to drop this into a production tool I plan to sell?

is licensed under GPLv2 for open-source use, with a separate commercial license required once the code ships in a production deployment

Languages

Not documented

Score card

  1. Shipping velocity releases a month, last 12 months
  2. Documentation quality release-notes rubric, 0–100
  3. Breaking-change discipline how rarely a release breaks users, and notice given
  4. Maintenance risk quiet time against its own cadence, maintainers
  5. Innovation & surface new capabilities, API and MCP surface
  6. Community health
  7. Contributor trend distinct committers, this year against last
  8. Maintainer concentration bus factor now against a year ago
  9. Issue backlog trend issues closed per issue opened, 12 months
  10. Responsiveness median time to a maintainer’s first reply

Nine scores for Keystone, each built from the releases, notes and API history this site tracks — and, on Researcher and Business, where it stands among every measured tool in its category and how that has moved.

Score cards are part of every paid plan.

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Each score is 0–100 on a published rubric, derived from data this site already shows. A dimension we cannot measure says so — it is never scored 0 and never enters a rank.

How this is scored
  • Shipping velocity — releases a month over the last 12 months, on a log scale where 16 a month scores 100. Needs 3 releases in the window.
  • Documentation quality — the release-notes rubric published on the analytics page, unchanged.
  • Breaking-change discipline — the share of releases carrying a breaking change (none scores 100, half or more scores 0). Only projects that label breaking changes are measured: a clean record cannot be told from an unlabelled one.
  • Maintenance risk — quiet time measured against the tool's own release cadence (quiet longer than 90 days and three typical gaps scores 0), plus the number of active maintainers and whether contributors are growing, where known. Higher is lower risk.
  • Innovation & surface — new capabilities in the feature ledger this year, API and MCP operations added, and the share of commits that are features: the mean of whichever we hold.
  • Community health (open-source tools only) — each is a direction, not a size: contributors this year against last, the bus factor now against a year ago, and issues closed per issue opened, where steady scores 50, doubled 100 and halved 0; plus the median time to a maintainer's first reply (an hour scores about 100, a month or more 0). A commercial card has no repository and carries none of the four.
  • Documented delivery (commercial tools) — when a vendor's documented new capabilities have slowed against its own baseline, that counts against the overall standing as heavily as two low dimensions. Steady delivery, or too little history to judge, leaves the standing alone; it is never a sixth score.
  • Open-source tools are scored on repository signals; commercial tools on their published changelog. Ranks compare tools within one category and one profile and need at least five measured peers; the overall standing needs three ranked dimensions. Best-in-breed or consolidator is a shape, not a quality, and is never scored.

Release-note detail over time

See how much detail Keystone puts in its release notes, quarter by quarter, and compare it with tracked tools in the same category. This history uses up to ten retained, reviewed notes per tool; sparse or blank older quarters may reflect that limit.

Checking release-note history…

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Releases

Nothing shipped since we started watching. Releases and docs updates land here as they happen.

last release Jun 21, 2020 · watching since Jul 18, 2026

Project health

Issue, contributor and maintainer activity in keystone-engine/keystone, 2023-10 – 2026-09, as of 2026-09-25. Twelve-month figures first; the trend lines run the whole window.

  1. Contributors 1 +1 vs prior 12 months
  2. Maintainers 0 +0 joined · −0 left, last 12 months
  3. Bus factor 0 committers behind half the commits
  4. Community-filed 100% of issues opened, last 12 months
  5. Median time to close < 1 day first maintainer reply 0 hours
  6. Open backlog 216 of 350 issues ever filed
  1. Issues opened / month 0 · 0 communitymaintainers
  2. Open backlog 216
  3. Contributors / month 0
  4. Commits / month 0
  5. Stars 2,636
Issue themes, last 12 months
  • other 100%

Counts from the project's public repository and git history; no individuals are identified. Maintainers are the committers covering 80% of the last year's commits. how we measure this

Libraries its release ships

What its latest release locks, checked against known advisories.

None of its release's images build from a lockfile we can read.

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