Protocol Adoption Index
Quarterly tracking of UCP, ACP, and AP2 adoption rates across five industry verticals. Based on automated technical compliance checks across 500+ enterprise domains per quarter. The benchmark dataset for agentic commerce protocol readiness.
Q1 2026 Headline Numbers
Key takeaway: UCP is accelerating fastest — up 54% quarter-over-quarter — driven by Google AI Mode's preference for merchants with UCP manifests. ACP adoption lags UCP by roughly 9 percentage points, reflecting the additional technical complexity of checkout API integration. AP2 adoption remains lowest but shows strong growth in Financial Services where audit trail requirements make Verifiable Credentials non-optional.
Adoption by Industry — Q3 2025 to Q1 2026
Data from automated compliance checks of .well-known protocol endpoints. Percentages represent the share of surveyed enterprise domains with fully functional endpoints.
B2B SaaS
Accelerating| Protocol | Q3 2025 | Q4 2025 | Q1 2026 | QoQ Change |
|---|---|---|---|---|
| UCP | 18% | 26% | 34% | +8pp |
| ACP | 9% | 14% | 18% | +4pp |
| AP2 | 3% | 6% | 9% | +3pp |
Retail
Accelerating| Protocol | Q3 2025 | Q4 2025 | Q1 2026 | QoQ Change |
|---|---|---|---|---|
| UCP | 14% | 21% | 28% | +7pp |
| ACP | 8% | 13% | 19% | +6pp |
| AP2 | 2% | 4% | 6% | +2pp |
Financial Services
Steady| Protocol | Q3 2025 | Q4 2025 | Q1 2026 | QoQ Change |
|---|---|---|---|---|
| UCP | 12% | 17% | 21% | +4pp |
| ACP | 6% | 9% | 11% | +2pp |
| AP2 | 7% | 10% | 12% | +2pp |
Travel
Steady| Protocol | Q3 2025 | Q4 2025 | Q1 2026 | QoQ Change |
|---|---|---|---|---|
| UCP | 6% | 10% | 15% | +5pp |
| ACP | 3% | 6% | 8% | +2pp |
| AP2 | 1% | 2% | 3% | +1pp |
Healthcare
Slow| Protocol | Q3 2025 | Q4 2025 | Q1 2026 | QoQ Change |
|---|---|---|---|---|
| UCP | 3% | 5% | 8% | +3pp |
| ACP | 1% | 2% | 3% | +1pp |
| AP2 | 2% | 3% | 4% | +1pp |
Source: Adam Silva Consulting Protocol Adoption Index. n=100 enterprise domains per industry per quarter. "pp" = percentage points. Methodology: automated HTTP checks of standardized .well-known protocol endpoint paths.
Methodology
Domain Selection
100 enterprise domains per vertical are selected using a stratified sample methodology: 30 large-cap ($1B+ revenue), 40 mid-market ($100M-$1B), and 30 emerging ($10M-$100M). Domains are held constant across quarters to enable longitudinal comparison. New cohorts are added annually.
Compliance Checks
Automated HTTP GET requests to standardized .well-known endpoint paths: /ucp/manifest.json, /acp/config.json, /ap2/mandates.json. Endpoints are scored as compliant only if they return valid JSON with required protocol fields — not just a 200 HTTP status code. Checks run first week of each quarter.
Quality Standards
Compliance requires: (1) valid JSON response, (2) correct Content-Type header (application/json), (3) required protocol version field present, (4) at least one capability or transport declared, (5) no authentication required for the manifest itself. Partial compliance is not counted.
Limitations
The index measures technical endpoint presence, not implementation quality. A minimal manifest with a single product counts equally with a comprehensive implementation covering all transports. The Agentic Commerce Readiness Index (published in the State of Agentic Commerce report) provides the quality-weighted alternative metric.
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