Open WebUI vs Tambo
An independent, evidence-based trust comparison of Open WebUI and Tambo, two UI & App Builders projects in the HVTracker registry. Scores come from public, checkable signals — supply-chain provenance, OSSF Scorecard, maintenance, and adoption — not popularity.
Tambo leads on trust — 83.7/100 (Grade A) vs 82.2/100 (Grade A), a 1.5-point gap. Note: Tambo's evidence coverage is thinner (coverage B vs A) — its score rests on fewer independent signal types. Full breakdown below.
| Signal | Open WebUIopen-webui/open-webui | Tambotambo-ai/tambo |
|---|---|---|
| HVTrust score | 82.2 | 83.7 |
| Evidence grade | A | A |
| Coverage grade | A | B |
| Overall rank | #53 | #47 |
| Rank in UI & App Builders | #4 | #3 |
| GitHub stars | 147.8k | 11.2k |
| Last updated | today | today |
| Build provenance | Yes | Yes |
| OSSF Scorecard | 5.6 / 10 | 5.3 / 10 |
| License | NOASSERTION | MIT |
| Downloads | 350k/wk | 6k/wk |
| Trust dimensions (points earned) | ||
| Safety / integrity / 25 | 16.9 | 19.1 |
| Identity & provenance / 18 | 18.0 | 18.0 |
| Transparency / 17 | 13.3 | 13.0 |
| Maintenance / 20 | 20.0 | 17.0 |
| Adoption / 20 | 19.8 | 14.8 |
| Runtime capability surface (full matrix) | ||
| MCP server | — | Declared |
| External providers | 12 — Amazon Bedrock, Anthropic, Brave Search, … | 2 — Anthropic, OpenAI |
| Requires API keys | Yes | Yes |
| Plugin surface | plugins | plugins |
| Provenance drift | Unknown | Match |
How to read this: HVTrust (0–100) weighs supply-chain signals (provenance, OSSF Scorecard, signed commits, open license) alongside real-world adoption, scaled by an evidence-confidence factor. Grade bands: A ≥ 80, B ≥ 65, C ≥ 50, D < 50. Signals refresh daily. Full methodology v4.2 →