Java + GraalVM Truffle. Native Image boots in milliseconds.
Audit-trail by default
Every evaluation hash-chained with SHA-256. Tamper-evident replay.
Open lexicons, bring your own
English, 中文, Deutsch ship today. Add a language with a config file.
🌍 Policies, workflows, decisions — in your own language
Express loan-eligibility checks, approval-gate workflows, routing decisions, and pricing rules in English, Simplified Chinese, or German. Same semantics, same engine. Adding a fourth language is a configuration task, not an engineering one.
🤖 AI drafts. You review.
Built-in LLM assistance generates rule drafts from plain prompts, explains existing rules, and auto-repairs syntax errors. Streaming over SSE, validated before suggested.
⚡ Production-grade execution
Java + GraalVM Truffle interpreter for high-throughput evaluation. Native Image builds boot in milliseconds. P99 latency under 200ms.
🔒 Tamper-evident audit
Every policy evaluation is recorded in the engine's tamper-evident AuditLog, hash-chained with SHA-256. Replay any historical decision deterministically — clocks and UUIDs are controlled at runtime.
🏢 SaaS or self-hosted
Use aster-lang.cloud for managed multi-tenant, or deploy to your own K3S cluster via ArgoCD GitOps. Your data, your jurisdiction.
🧰 Drop-in via REST, GraphQL, or WebSocket
Submit policy source inline or reference a stored policy by ID. Batch evaluate. Stream traces. See Cloud API docs for transports + auth.
Aster Cloud
Run them on Aster Cloud
Policy evaluation, workflow audit logs, and batch decisions — all served over REST, GraphQL, and WebSocket by the hosted engine.
You want to write CNL rules and run them. Start in the browser playground; integrate via @aster-cloud/aster-lang-ts. Need a managed engine? Aster Cloud has hosted REST / GraphQL / WS.
Aster Lang is a multi-lingual Controlled Natural Language (CNL) for writing executable business logic — loan-eligibility policies, approval-gate workflows, routing decisions, pricing rules, and anything else where the rule should be readable by humans and runnable by machines.
The language treats policies, workflows, and decisions as first-class concepts: the same syntax expresses an eligibility check, an approval flow, or a routing rule. The engine compiles all three to the same audit-grade execution path.
aster
Module aster.finance.loan.Define Applicant has creditScore as Int, annualIncome as Int.Rule evaluateLoanEligibility given applicant as Applicant, produce Text: If applicant.creditScore at least 700 If applicant.annualIncome at least 50000 Return "approved". Return "rejected".
The same rule works in 中文:
aster
模块 aster.finance.loan。定义 申请人 包含 信用分 as 整数，年收入 as 整数。规则 evaluateLoanEligibility 给定 申请人 as 申请人，产出 文本： 如果 申请人.信用分 至少 700 如果 申请人.年收入 至少 50000 返回 "已批准"。 返回 "已拒绝"。
Both are parsed, type-checked, and executed by the same engine.
