Diffbot vs Stardog
Diffbot vs Stardog: side-by-side comparison of two knowledge-graph platforms systems — architecture, taxonomy, license, pricing, MCP/A2A support, and direct edges.
Cost & capability
| Diffbot | Stardog | |
|---|---|---|
| Cost tier | mid | — |
Where they differ (11)
Rows where both sides have data and the values disagree — the shortlist of dimensions that actually distinguish these two systems.
| Diffbot | Stardog | |
|---|---|---|
| Type | Auto-extracted KG from web crawl | RDF semantic platform + Voicebox AI |
| Created | 2008 | 2010 |
| Pricing | Free $0/month (10,000 credits); Startup $299/month (250,000 credits, overage $0.001/credit); Startup Plus $899/month (1,000,000 credits, overage $0.0009/credit); Enterprise custom | Stardog Free (renewable 1-year license, commercial use allowed, no HA/caching/backups); Enterprise on-prem and cloud quote-based |
| Funding | $12.5M total (Seed + Series A 2016) | $32M Series C (last known) · 2022-01 |
| Backend storage | custom | custom (RDF triple store) |
| Deployment | Managed-only | Both |
| API surface | REST + GraphQL (DQL Knowledge Graph; Enhance, Extract APIs) | REST, SPARQL, SDK: Java, Python, JS |
| Embedding | locked | BYO |
| Multi-tenancy | hard-isolation | Per-database access control; on-prem / private-cloud / SaaS options |
| MCP | yes — official diffbot/diffbot-mcp server (extract, search_web, crawl, entity resolution tools) | yes — official Stardog Cloud MCP server (stardog-union/stardog-cloud-mcp; remote setup in beta) |
| OpenTelemetry | no first-party OpenTelemetry exporter documented; standard logs/metrics typically available. | first-class — Prometheus + OTel |
At a glance
| Diffbot | Stardog | |
|---|---|---|
| Section | Knowledge-graph platforms | Knowledge-graph platforms |
| Tier | T1 | T1 |
| Type | Auto-extracted KG from web crawl | RDF semantic platform + Voicebox AI |
| Created | 2008 | 2010 |
| Pricing | Free $0/month (10,000 credits); Startup $299/month (250,000 credits, overage $0.001/credit); Startup Plus $899/month (1,000,000 credits, overage $0.0009/credit); Enterprise custom | Stardog Free (renewable 1-year license, commercial use allowed, no HA/caching/backups); Enterprise on-prem and cloud quote-based |
| Funding | $12.5M total (Seed + Series A 2016) | $32M Series C (last known) · 2022-01 |
| Backend storage | custom | custom (RDF triple store) |
| Deployment | Managed-only | Both |
| API surface | REST + GraphQL (DQL Knowledge Graph; Enhance, Extract APIs) | REST, SPARQL, SDK: Java, Python, JS |
| Embedding | locked | BYO |
| Multi-tenancy | hard-isolation | Per-database access control; on-prem / private-cloud / SaaS options |
| MCP | yes — official diffbot/diffbot-mcp server (extract, search_web, crawl, entity resolution tools) | yes — official Stardog Cloud MCP server (stardog-union/stardog-cloud-mcp; remote setup in beta) |
| A2A | no Google A2A (Agent2Agent) integration documented as of 2026-05. | no Google A2A (Agent2Agent) integration documented as of 2026-05. |
| OpenTelemetry | no first-party OpenTelemetry exporter documented; standard logs/metrics typically available. | first-class — Prometheus + OTel |
| Optimised for | relationship modeling + reasoning + governance over pure vector | relationship modeling + reasoning + governance over pure vector |
| Anti-fit | not for purely-vector or simple-RAG use cases (graph adds setup cost) | not for purely-vector or simple-RAG use cases (graph adds setup cost) |
Pros & cons
Diffbot
Pros: Pre-built knowledge graph of the web (KGoW) — you don't build the graph, you query someone else's; saves enormous extraction cost.
Cons: Quality is bounded by Diffbot's extraction; no schema control; not appropriate for proprietary internal data.
Stardog
Pros: Mature semantic graph + virtualization (data fabric over relational/cloud sources); strong inference rules engine.
Cons: Enterprise-tier pricing and complexity; smaller community than Neo4j; license shifted to Stardog Studio commercial focus.