Rate Verification

Every rate returned by /v1/rates/live includes a status and (for Builder+) a confidence score, computed by comparing the exchange VWAP against an independently calculated synthetic price.

How it works

1. FX rate collection -- Hourly USD/fiat rates (USD/NGN, USD/ZAR, USD/KES, USD/GHS, USD/UGX) from ExchangeRate-API.

2. Synthetic price -- For each crypto/fiat pair:

   CRYPTO/FIAT (synthetic) = CRYPTO/USDT (Binance) x USD/FIAT (ExchangeRate-API)

3. Deviation check -- The verification engine computes percentage divergence between exchange VWAP and synthetic price against per-pair thresholds.

Status levels

Status	Confidence	Meaning
verified	0.95	Divergence within threshold. Rate is reliable.
caution	0.80	Divergence exceeds threshold but within 2x. Warrants attention.
unverified	0.60	Divergence exceeds 2x threshold. Use synthetic price as fallback.

Per-pair thresholds

Currency	Verified	Caution	Unverified
Default (ZAR, KES, GHS, UGX)	≤2%	2–5%	>5%
NGN	≤5%	5–10%	>10%

NGN pairs have higher tolerance due to the parallel market premium. USDTNGN routinely trades 5--10% above the official rate (legitimate market behavior).

Tier-gated fields

Field	Free	Builder+	Enterprise
status	Yes	Yes	Yes
data_quality	Yes	Yes	Yes
confidence	--	Yes	Yes
synthetic_divergence_pct	--	Yes	Yes
notes	--	Yes	Yes
pricing (via include_synthetic/include_sources)	--	Yes	Yes
audit (via include_audit)	--	--	Yes

Example response (data.{PAIR} format)

Free tier:

{
  "data": {
    "BTCNGN": {
      "rate": 92745268.5,
      "calculation": "vwap",
      "data_freshness_seconds": 7,
      "sources": [
        {"exchange": "luno", "rate": 92948735.0, "time": "2026-04-03T01:45:00+00:00"},
        {"exchange": "quidax", "rate": 92541802.0, "time": "2026-04-03T01:45:00+00:00"}
      ],
      "status": "verified",
      "data_quality": "high"
    }
  },
  "meta": {"request_id": "...", "timestamp": "...", "latency_ms": 5}
}

Builder+ tier adds confidence, synthetic_divergence_pct, and notes to each pair object.

Certificates

Enterprise customers can retrieve cryptographically signed rate attestation certificates via the Certificates endpoint. Each certificate contains HMAC-SHA256 signed audit data for a specific pair and timestamp, suitable for regulatory reporting.

Inline audit hashes

Enterprise customers can pass include_audit=true on /v1/rates/live to receive the HMAC-SHA256 audit hash inline:

"audit": {"signature": "sha256:d842a519e279..."}

Premium and divergence analysis

The Premium Analysis endpoint provides time-series data on the divergence between exchange VWAP and synthetic cross-rate prices. Available to Builder tier and above.

Recommended usage

• Pricing engines: Only use rates with status: "verified". Fall back to the synthetic price (via include_synthetic=true) when status is unverified.
• Monitoring: Alert when any pair transitions to caution or unverified.
• Audit/compliance: Enterprise customers should use include_audit=true or Certificates for the full verification trail.