Quantum Trust Index

The Quantum Trust Index (QTI) is a single 0–1000 score that summarises how much a quantum backend can be trusted for production workloads. Where an ACOS certificate is a pass/fail badge at a point in time, the Trust Index is a living, rankable score built from real, auditable signals — so you can compare backends, monitor drift, and pick the right hardware with one number. Every score is transparent: each contributing signal reports whether it is backed by measured data or an inferred fallback, so the index never presents a guess as if it were an observation.

curl https://api.softquantus.com/api/v1/acos/trust-index

How the score is built

The 0–1000 score is the sum of four weighted sub-scores:

Signal	Max	What it measures
ACOS-ISA Conformance	500	The certification result — tier achieved and pass rate across the 10 ACOS-ISA tests. An expired/suspended certificate still counts, but at half weight.
Evidence Integrity	200	Whether a hash-consistent evidence bundle exists for the backend. Present + signed = full; present but unsigned (today’s `sealed_unsigned` bundles) = partial; absent = zero.
Reliability & Availability	200	Live provider health — availability, latency and queue depth. When no telemetry is available a clearly-flagged neutral baseline (60 %) is used.
Certification Recency	100	How fresh the certification is relative to its validity window. A brand-new cert scores full; the score decays linearly to zero as it approaches expiry.

Total = 1000.

Trust bands

The numeric score maps to a labelled band (with a badge colour) for at-a-glance ranking:

Score	Band	Badge
≥ 900	Platinum Trust	◆
750 – 899	Gold Trust	●
600 – 749	Silver Trust	●
400 – 599	Bronze Trust	●
< 400	Unrated	○

`measured` vs `fallback`

Each sub-score carries a source field:

measured — backed by observed data (a real certificate, a verified evidence bundle, live provider health, an actual issue date).
fallback — no data available, so a conservative default is applied and clearly marked (e.g. reliability with no telemetry, or a backend that has never been certified).

This lets buyers distinguish “we measured this and it’s low” from “we don’t have data yet”.

Endpoints

Score every certified backend (public, ranked high → low):

curl https://api.softquantus.com/api/v1/acos/trust-index

{
  "trust_indexes": [
    {
      "backend_id": "sim_aer",
      "backend_name": "Aer",
      "provider": "SoftQuantus",
      "score": 875,
      "max_score": 1000,
      "band": "gold",
      "band_label": "Gold Trust",
      "band_color": "#FFD700",
      "subscores": [
        { "key": "conformance", "label": "ACOS-ISA Conformance", "value": 500, "max": 500, "source": "measured", "detail": "full — 100% pass rate, status=active." },
        { "key": "evidence",    "label": "Evidence Integrity",   "value": 100, "max": 200, "source": "measured", "detail": "Bundle present and hash-consistent but unsigned." },
        { "key": "reliability", "label": "Reliability & Availability", "value": 175, "max": 200, "source": "measured", "detail": "available, latency=0ms, queue=n/a." },
        { "key": "recency",     "label": "Certification Recency", "value": 100, "max": 100, "source": "measured", "detail": "Certified 0d ago of 90d validity." }
      ],
      "computed_at": "2026-07-04T21:13:00Z"
    }
  ],
  "total": 1
}

Get the full breakdown for a single backend:

curl https://api.softquantus.com/api/v1/acos/trust-index/ibm_fez

In the portal

The QCOS Compatible page at platform.softquantus.com renders the Trust Index as a ranked table with band badges and per-signal bars, plus a self-serve Certify flow and an Evidence tab that verifies bundles client-side. See Using the QCOS Compatible page.

Why it matters for buyers

Procurement — rank candidate backends by a single, defensible number instead of comparing raw calibration data.
Continuous assurance — a backend that lets its certification lapse or drops in availability loses points automatically.
Trust, not marketing — every point is traceable to a certificate, a verifiable sealed evidence bundle, or live telemetry.

Core

Modules

Certification

Quantum Trust Index

Quantum Trust Index

How the score is built

Trust bands

`measured` vs `fallback`

Endpoints

In the portal

Why it matters for buyers

​Quantum Trust Index

​How the score is built

​Trust bands

​measured vs fallback

​Endpoints

​In the portal

​Why it matters for buyers

Quantum Trust Index

How the score is built

Trust bands

`measured` vs `fallback`

Endpoints

In the portal

Why it matters for buyers