The Ayubaba Standard
How Engineering Verification Works
Every product listed on Ayubaba undergoes the same rigorous process, carried out by a qualified electronics engineer, not an algorithm, not a tick-box exercise.
Step 1
Physical Engineering Assessment
Each product is assessed hands-on by a trained engineer using calibrated diagnostic tools. Condition, functionality, provenance, and safety. Nothing is assumed from listed specs. Every check is independently conducted.
- Condition grading against standardised criteria
- Functional testing of all key features
- Wi-Fi and connectivity verification
- IMEI check vs. National Stolen Property Database
- Physical safety and structural integrity
- Water damage indicator inspection
Step 2
Verification Record Generation
Assessment results are locked into the Engineering Verification System (EVS) as an immutable record. At submission, the record is sealed with a SHA-256 cryptographic hash, so any later change to the stored data is detectable. Re-assessments never overwrite a record: they issue a new version, and every previous version remains permanently preserved for audit and buyer trust.
- Unique EVS ID assigned per unit
- Record sealed with a SHA-256 cryptographic hash
- Measured values, diagnostic tools and evidence recorded per check
- Data wipe certification (BS EN 15713)
- Immutable versioning: previous records are never deleted
- PDF Verification Record with QR verification link
Step 3
Verified Listing
Only products whose latest EVS record completes every mandatory check are eligible for listing; publishing is blocked otherwise. The complete record, its confidence scores and its integrity status are published on every product page, and anyone can independently verify a record at any time via its public verification page or the QR code on the PDF.
- All mandatory checks required to list, enforced automatically
- Technical confidence and risk scores on every record
- Full record and integrity status on every product page
- Public verification page for every EVS ID
- Every publish, PDF and integrity event logged in an append-only audit trail
- 30-day return guarantee
The Scores
What the confidence scores mean
Every EVS record carries deterministic, rule-based scores computed at submission time from the engineer's check results, and never adjusted afterwards. The reasons behind each score are stored on the record itself and shown alongside it, so you can see exactly why a product earned its numbers.
Technical Confidence (0–100)
Starts at 100. Failed checks cost 25 points if mandatory or 15 if optional, advisories cost 8, and each uncompleted mandatory check costs 20. Thin evidence (completed checks without measured values or evidence) costs up to 10 more. 90+ is Excellent, 75+ Good, 60+ Fair.
Product Risk (0–100)
Starts at 0; lower is better. The same signals add risk, weighted toward safety-critical checks: a failed battery, data-wipe or provenance check adds 35 points, other failed mandatory checks 25, optional failures 15, advisories and missing mandatory checks 8–20.
Sustainability Confidence (0–100)
Only on Verified Sustainable products. Scored from sustainability-scope checks alone: each failure costs 30 points, each uncompleted check 25, and each advisory 12.
- Scores are computed by fixed rules, with no manual adjustment and no algorithmic opacity
- The reasons behind each score are stored on the record and shown with it
- Safety-critical checks (battery, data wipe, provenance) are weighted heaviest
- A product cannot be listed if any mandatory or safety-critical check fails or is incomplete
- Scores and reasons are sealed under the record's SHA-256 hash
- Re-assessment issues a new record version; scores are never edited in place