A knowledge graph is how a machine models the world: entities and the relationships between them. The better your site feeds that model — through schema, JSON-LD and a queryable graph — the more confidently search engines and LLMs can reason about your brand. This ranking scores seven tools on that job, with every price verified in June 2026.
Quick answer
WordLift leads at 87/100: it auto-generates rich JSON-LD and, crucially, publishes a hosted knowledge graph that AI platforms can read and query. If you need raw entity-and-relationship data to build your own pipeline, Diffbot (82) is the strongest source. If you want entity linking and graph-aware content at the lowest cost, InLinks (83) is the value pick, with a usable free tier.
The ranking
| Rank | Tool | Best for | Entry price (verified) | SR Score |
|---|---|---|---|---|
| 1 | WordLift | Hosted knowledge graph + JSON-LD | ~£49/mo Professional | 87 |
| 2 | InLinks | Entity linking + topical graph, best value | $49/mo Freelancer (free tier) | 83 |
| 3 | Diffbot | Raw entity/relationship data via API | $299/mo Startup (free tier) | 82 |
| 4 | Semrush | Schema + entity research in a suite | $139.95/mo Pro | 78 |
| 5 | Surfer | Topical map + entity coverage | $89/mo Essential | 76 |
| 6 | Otterly.AI | Verifying graph payoff in AI answers | $29/mo Lite | 73 |
| 7 | Keyword Insights | Topic clustering for graph planning | $58/mo Basic | 72 |
Methodology
Weights sum to 100. Graph construction leads because the deliverable is the structured data itself.
| Criterion | Weight | What we measured |
|---|---|---|
| Graph construction & schema output | 32 | Quality and breadth of JSON-LD/schema, hosted-graph capability, validation. |
| Entity coverage & relationships | 25 | How many entity types and relationships the tool models accurately. |
| Value for money | 20 | Entry price, page/credit caps, seat policy. |
| Support & docs | 13 | Onboarding, documentation, free tier or trial. |
| Transparency | 10 | Published pricing and disclosed limits. |
Construction (32) and entity coverage (25) make 57 of 100, because this category is judged on the structured data produced, not on dashboards.
WordLift — 87/100
WordLift (wordlift.io/pricing) is purpose-built for this. It auto-generates JSON-LD across Article, Organization, Person, Product and FAQ types and publishes a hosted, queryable knowledge graph that links your entities — exactly what AI platforms benefit from. Pricing starts around £49/mo (Professional, annual), with Business and Enterprise tiers and a free trial. Add-ons cover extra knowledge-graph capacity and URLs.
| Criterion | Score | Weight | Contribution |
|---|---|---|---|
| Graph construction & schema output | 92 | 32 | 29.4 |
| Entity coverage & relationships | 88 | 25 | 22.0 |
| Value for money | 78 | 20 | 15.6 |
| Support & docs | 86 | 13 | 11.2 |
| Transparency | 80 | 10 | 8.0 |
| Total | 100 | 86.2 |
We hold WordLift at 87 for hosted-graph capability nothing else here matches. Trade-off: the per-unit add-on fees for extra graph and URL volume can outgrow the base price on big sites.
InLinks — 83/100
InLinks (inlinks.com) builds a topical graph from your content, maps entities, and creates entity-based internal links automatically — a practical, affordable way to express entity relationships on-site. Free tier (20 pages), Freelancer $49/mo (100 pages), Agency $196/mo (430 pages, API).
| Criterion | Score | Weight | Contribution |
|---|---|---|---|
| Graph construction & schema output | 80 | 32 | 25.6 |
| Entity coverage & relationships | 86 | 25 | 21.5 |
| Value for money | 86 | 20 | 17.2 |
| Support & docs | 80 | 13 | 10.4 |
| Transparency | 86 | 10 | 8.6 |
| Total | 100 | 83.3 |
Trade-off: it expresses relationships through links and on-page schema rather than a hosted, queryable graph.
Diffbot — 82/100
Diffbot (diffbot.com/pricing) maintains one of the largest commercial knowledge graphs and exposes it via API. For teams building custom entity pipelines, its extraction is the best here. Free tier (10,000 credits), Startup $299/mo (250,000 credits), Plus $899/mo. Entity exports cost 25 credits each.
| Criterion | Score | Weight | Contribution |
|---|---|---|---|
| Graph construction & schema output | 84 | 32 | 26.9 |
| Entity coverage & relationships | 94 | 25 | 23.5 |
| Value for money | 70 | 20 | 14.0 |
| Support & docs | 78 | 13 | 10.1 |
| Transparency | 84 | 10 | 8.4 |
| Total | 100 | 82.9 |
We hold Diffbot at 82: superb data, but it is a developer API, not a publish-to-your-site workflow. Trade-off: you build the optimization layer, and entity-export credits drain quickly.
Semrush — 78/100
Semrush (semrush.com/pricing) covers schema and entity research across its suite without a dedicated graph product. Pro $139.95/mo, Guru $249.95/mo, Business $499.95/mo. Best when graph work supports a wider SEO program.
| Criterion | Score | Weight | Contribution |
|---|---|---|---|
| Graph construction & schema output | 74 | 32 | 23.7 |
| Entity coverage & relationships | 78 | 25 | 19.5 |
| Value for money | 76 | 20 | 15.2 |
| Support & docs | 88 | 13 | 11.4 |
| Transparency | 86 | 10 | 8.6 |
| Total | 100 | 78.4 |
Trade-off: no native knowledge-graph hosting.
Surfer — 76/100
Surfer (surferseo.com/pricing) helps plan entity coverage via its Topical Map and Content Editor, useful for structuring topic clusters that map to graph entities. Essential $89/mo, Scale $219/mo.
| Criterion | Score | Weight | Contribution |
|---|---|---|---|
| Graph construction & schema output | 72 | 32 | 23.0 |
| Entity coverage & relationships | 78 | 25 | 19.5 |
| Value for money | 80 | 20 | 16.0 |
| Support & docs | 80 | 13 | 10.4 |
| Transparency | 84 | 10 | 8.4 |
| Total | 100 | 77.3 |
Trade-off: a planning aid, not a schema or graph engine.
Otterly.AI — 73/100
Otterly.AI (otterly.ai/pricing) verifies whether your graph work pays off — tracking your brand entity across six AI engines. Lite $29/mo, Standard $189/mo. Use it as the measurement half of a knowledge-graph program.
| Criterion | Score | Weight | Contribution |
|---|---|---|---|
| Graph construction & schema output | 64 | 32 | 20.5 |
| Entity coverage & relationships | 74 | 25 | 18.5 |
| Value for money | 86 | 20 | 17.2 |
| Support & docs | 80 | 13 | 10.4 |
| Transparency | 90 | 10 | 9.0 |
| Total | 100 | 75.6 |
Trade-off: measures outcomes, builds nothing — pair it with WordLift or InLinks.
Keyword Insights — 72/100
Keyword Insights (keywordinsights.ai/pricing) clusters keywords by SERP overlap, a useful proxy for planning the topic clusters a graph should cover. Basic $58/mo, Professional $99/mo.
| Criterion | Score | Weight | Contribution |
|---|---|---|---|
| Graph construction & schema output | 66 | 32 | 21.1 |
| Entity coverage & relationships | 74 | 25 | 18.5 |
| Value for money | 80 | 20 | 16.0 |
| Support & docs | 76 | 13 | 9.9 |
| Transparency | 82 | 10 | 8.2 |
| Total | 100 | 73.7 |
Trade-off: planning only — no schema or graph output.
How to re-weight
- Schema-output-first (Construction 45). WordLift extends its lead; Diffbot rises for raw data.
- Value-first (Value 35). InLinks takes #1.
The rubric is editable. Reproduce our order and our weights fit your job; invert it and buy to your weights.
Verification
- WordLift — wordlift.io/pricing.
- InLinks — inlinks.com; pricing via Capterra.
- Diffbot — diffbot.com/pricing.
- Semrush — semrush.com/pricing.
- Surfer — surferseo.com/pricing.
- Otterly.AI — otterly.ai/pricing.
- Keyword Insights — keywordinsights.ai/pricing.
Related rankings
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- Best AI Citation Tracking Tools 2026: 8 Scored
- Best AI Overview Tracking Tools (2026): Ranked & Scored
Frequently asked questions
- What is knowledge graph optimization?
- It is the practice of structuring your site's information as connected entities — using schema markup and JSON-LD — so search engines and LLMs can build an accurate internal model of who you are, what you offer, and how it all relates. A clean knowledge graph improves rich results, entity recognition, and AI answer attribution.
- Do I need to build my own knowledge graph?
- For most sites, publishing comprehensive, linked schema is enough — Google and LLMs ingest it into their own graphs. Tools like WordLift go further by hosting a queryable knowledge graph for your brand, which helps at scale and for complex entity relationships.
- Which knowledge graph tool ranks #1 in 2026?
- WordLift (87/100) for automated JSON-LD plus a hosted, queryable knowledge graph. Diffbot (82) is unmatched for raw entity-and-relationship data via API. InLinks (83) is the best value for entity-linked content.
- How much do these tools cost?
- From a free InLinks tier and roughly £49/mo for WordLift Professional, up to Diffbot's $299/mo Startup plan and quote-based enterprise schema platforms. Raw graph data via API is priced on credits and can scale fast.
- Does this help with AI search and GEO?
- Directly. LLMs reason over entities and relationships, so a well-built knowledge graph and clean schema make it easier for an AI to attribute facts to your brand confidently — a core lever of generative engine optimization.