diff --git a/backend-compliance/compliance/api/__init__.py b/backend-compliance/compliance/api/__init__.py
index 8faf5866..3c47c08d 100644
--- a/backend-compliance/compliance/api/__init__.py
+++ b/backend-compliance/compliance/api/__init__.py
@@ -78,6 +78,7 @@ _ROUTER_MODULES = [
     "template_rule_routes",
     "specialist_agent_routes",
     "reasoning_routes",
+    "onboarding_routes",
 ]
 
 _loaded_count = 0
diff --git a/backend-compliance/compliance/api/onboarding_routes.py b/backend-compliance/compliance/api/onboarding_routes.py
new file mode 100644
index 00000000..f8ef92a8
--- /dev/null
+++ b/backend-compliance/compliance/api/onboarding_routes.py
@@ -0,0 +1,72 @@
+"""Onboarding Advisor endpoint — exposes the existing Smart Onboarding Advisor at runtime.
+
+This adds NO new reasoning logic. It exposes the already-built, tested orchestration (Signal Producers
+-> Normalizer -> Silent Knowledge Pass -> Advisor) through one runtime endpoint. No DB, no persistence.
+
+  POST /onboarding/advisor-start  — (company + certs + target + scanner findings) -> advisory payload
+  GET  /onboarding/targets        — the supported target ids
+"""
+
+import logging
+from typing import List, Optional
+
+from fastapi import APIRouter, HTTPException
+from pydantic import BaseModel, Field
+
+from compliance.onboarding import (
+    AdvisorMeasure,
+    AdvisorQuestion,
+    InferredAssumption,
+    ProducedSignal,
+    RejectedAssumption,
+)
+from compliance.services.onboarding_service import run_advisor, supported_targets
+
+logger = logging.getLogger(__name__)
+router = APIRouter(prefix="/onboarding", tags=["onboarding"])
+
+
+class OnboardingAdvisorRequest(BaseModel):
+    company: str = ""
+    industry: Optional[str] = None
+    products: List[str] = Field(default_factory=list)
+    markets: List[str] = Field(default_factory=list)
+    certifications: List[str] = Field(default_factory=list)
+    known_evidence: List[str] = Field(default_factory=list)
+    target: str = "CRA"
+    scanner_findings: List[ProducedSignal] = Field(default_factory=list)   # adapters upstream produced these
+
+
+class AdvisorResponse(BaseModel):
+    silent_intake_summary: str = ""
+    headline: str = ""
+    auto_detected: List[str] = Field(default_factory=list)
+    inferred_assumptions: List[InferredAssumption] = Field(default_factory=list)
+    rejected_assumptions: List[RejectedAssumption] = Field(default_factory=list)
+    top_5_questions: List[AdvisorQuestion] = Field(default_factory=list)
+    capability_delta: List[str] = Field(default_factory=list)
+    top_measures: List[AdvisorMeasure] = Field(default_factory=list)
+    evidence_requests: List[str] = Field(default_factory=list)
+    unsupported_domains: List[str] = Field(default_factory=list)
+    completeness_summary: str = ""
+
+
+@router.get("/targets")
+def list_targets() -> dict:
+    return {"targets": supported_targets()}
+
+
+@router.post("/advisor-start", response_model=AdvisorResponse)
+def advisor_start_endpoint(req: OnboardingAdvisorRequest) -> AdvisorResponse:
+    if req.target not in supported_targets():
+        raise HTTPException(status_code=404, detail="unsupported target '%s'; supported: %s" % (req.target, supported_targets()))
+    result, si_summary = run_advisor(
+        company=req.company, certifications=req.certifications, target=req.target,
+        signals=req.scanner_findings, known_evidence=req.known_evidence,
+        products=req.products, markets=req.markets, industry=req.industry or "")
+    return AdvisorResponse(
+        silent_intake_summary=si_summary, headline=result.headline, auto_detected=result.auto_detected,
+        inferred_assumptions=result.inferred_assumptions, rejected_assumptions=result.rejected_assumptions,
+        top_5_questions=result.next_best_questions, capability_delta=result.capability_delta,
+        top_measures=result.top_measures, evidence_requests=result.evidence_requests,
+        unsupported_domains=result.unsupported_domains, completeness_summary=result.completeness_summary)
diff --git a/backend-compliance/compliance/services/onboarding_service.py b/backend-compliance/compliance/services/onboarding_service.py
new file mode 100644
index 00000000..c57c4f0e
--- /dev/null
+++ b/backend-compliance/compliance/services/onboarding_service.py
@@ -0,0 +1,80 @@
+"""Onboarding Advisor service — the app-caller that loads knowledge and runs the pure orchestration.
+
+This is the SERVICE layer that makes the Smart Onboarding Advisor runtime-usable: it loads the curated
+knowledge (certification hypotheses, signal vocabulary + map, the target's required capabilities) once
+and calls the already-built, pure orchestration (normalize_signals -> silent_intake -> advisor_start).
+It adds NO new reasoning logic — it only exposes what exists. No DB, no persistence (by scope).
+"""
+
+from __future__ import annotations
+
+import os
+from typing import Any, Dict, List, Sequence, Tuple
+
+import yaml
+
+from compliance.onboarding import (
+    AdvisorResult,
+    CapabilityHypothesis,
+    OnboardingInput,
+    ProducedSignal,
+    SignalMapping,
+    SignalVocabularyEntry,
+    advisor_start,
+    normalize_signals,
+    resolve_for_certifications,
+    silent_intake,
+)
+from compliance.transition_reasoning import TargetRequirement
+
+_K = os.path.join(os.path.dirname(__file__), "..", "..", "knowledge")
+
+
+def _load(*parts: str) -> Any:
+    return yaml.safe_load(open(os.path.join(_K, *parts), encoding="utf-8"))
+
+
+_HYP_LIB = [CapabilityHypothesis(**h) for h in _load("certification_hypotheses", "hypotheses.yaml")["hypotheses"]]
+_VOCAB = [SignalVocabularyEntry(**v) for v in _load("onboarding", "signal_vocabulary.yaml")["signals"]]
+_SIGNAL_MAP = [SignalMapping(**m) for m in _load("onboarding", "intake_signal_map.yaml")["mappings"]]
+
+# target id -> transition pattern that defines its required capabilities (curated registry)
+_TARGET_PATTERNS = {
+    "CRA": "transition_pattern_iso27001_to_cra_maschinenvo_v1.yaml",
+    "TISAX": "transition_pattern_isms_to_tisax_v1.yaml",
+    "MDR": "transition_pattern_iso13485_to_medical_v1.yaml",
+    "Environmental": "transition_pattern_iso14001_to_environmental_v1.yaml",
+}
+
+
+def supported_targets() -> List[str]:
+    return sorted(_TARGET_PATTERNS)
+
+
+def _target(target_id: str) -> Tuple[List[TargetRequirement], Dict[str, List[str]]]:
+    pat = _load("transition_patterns", _TARGET_PATTERNS[target_id])
+    reqs = [TargetRequirement(capability_id=a["capability"]) for a in pat["likely_covered"]]
+    reqs += [TargetRequirement(capability_id=d["capability"], question_intent=d.get("needed_information", "verify_existence"),
+                               expected_evidence=d.get("expected_evidence", [])) for d in pat["delta_requirements"]]
+    covers = {d["capability"]: d.get("covers_targets", []) for d in pat["delta_requirements"]}
+    return reqs, covers
+
+
+def run_advisor(
+    company: str, certifications: Sequence[str], target: str,
+    signals: Sequence[ProducedSignal], known_evidence: Sequence[str],
+    products: Sequence[str], markets: Sequence[str], industry: str = "",
+) -> Tuple[AdvisorResult, str]:
+    """Producers (ProducedSignal) -> Normalizer -> Silent Pass -> Advisor. Returns an AdvisorResult.
+
+    `target` must be a supported target id. Raises KeyError otherwise (the handler maps it to 400/404).
+    """
+    reqs, covers = _target(target)
+    si = silent_intake(normalize_signals(signals, _VOCAB), _SIGNAL_MAP)
+    inp = OnboardingInput(company=company, industry=industry or None, products=list(products),
+                          markets=list(markets), certifications=list(certifications),
+                          known_evidence=list(known_evidence), target=[target])
+    result = advisor_start(
+        inp, resolve_for_certifications(certifications, _HYP_LIB), reqs, target_id=target,
+        covers_targets=covers, corpus_status={target: "validated"}, detected_capabilities=si.capability_ids())
+    return result, si.summary
diff --git a/backend-compliance/tests/test_onboarding_endpoint.py b/backend-compliance/tests/test_onboarding_endpoint.py
new file mode 100644
index 00000000..9029415a
--- /dev/null
+++ b/backend-compliance/tests/test_onboarding_endpoint.py
@@ -0,0 +1,53 @@
+"""POST /onboarding/advisor-start — the runtime endpoint that exposes the existing Advisor.
+
+Exercises the router in isolation (no DB, no full app): scanner findings (ProducedSignal) -> normalize
+-> Silent Pass -> Advisor -> the advisory payload. No new reasoning logic — just the wiring.
+"""
+
+from __future__ import annotations
+
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from compliance.api.onboarding_routes import router
+
+_app = FastAPI()
+_app.include_router(router)
+_client = TestClient(_app)
+
+_BODY = {
+    "company": "synthetic", "industry": "machine_builder", "products": ["parking payment system"],
+    "markets": ["EU"], "certifications": ["ISO27001", "ISO9001"], "known_evidence": ["CE process"],
+    "target": "CRA",
+    "scanner_findings": [
+        {"signal_id": "cyclonedx_found", "source_type": "repository", "evidence": "sbom", "provenance": "sbom.cdx.json"},
+        {"signal_id": "vdp_found", "source_type": "website", "provenance": "/.well-known/security.txt"},
+        {"signal_id": "risk_assessment_pdf", "source_type": "document", "provenance": "risk.pdf"},
+        {"signal_id": "cloud_hosted", "source_type": "product"},
+    ],
+}
+
+
+def test_targets_endpoint_lists_supported():
+    r = _client.get("/onboarding/targets")
+    assert r.status_code == 200
+    assert "CRA" in r.json()["targets"]
+
+
+def test_advisor_start_returns_full_payload():
+    r = _client.post("/onboarding/advisor-start", json=_BODY)
+    assert r.status_code == 200, r.text
+    d = r.json()
+    for field in ["silent_intake_summary", "inferred_assumptions", "rejected_assumptions",
+                  "top_5_questions", "capability_delta", "top_measures", "evidence_requests",
+                  "completeness_summary"]:
+        assert field in d
+    assert len(d["top_5_questions"]) <= 5
+    assert d["auto_detected"]                                    # Silent Pass recognised things from the scanners
+    assert "sbom_creation" not in {q["capability_id"] for q in d["top_5_questions"]}  # detected -> not asked
+
+
+def test_unknown_target_is_404():
+    body = dict(_BODY, target="NOPE")
+    r = _client.post("/onboarding/advisor-start", json=body)
+    assert r.status_code == 404