# Onto vs Jina Reader · Add scoring + safety to your AI reads > Jina Reader is great for free, no-signup Markdown extraction. Onto adds a 0–100 accuracy score, hallucination-risk flags, an MCP server, and a site-side SDK — the layer your agent needs to decide whether to trust a page. **Source:** /compare/jina-reader **Extracted:** 2026-05-20T20:59:17.609Z --- Compared · Onto vs Jina Reader ## Jina gives you Markdown. _Onto gives you Markdown plus the score._ Jina Reader is excellent for free, no-signup Markdown extraction and is a natural fit if you live in the Jina embeddings ecosystem. Onto adds a 0–100 accuracy score, hallucination-risk flags, an MCP server, and a site-side SDK — so your agent knows whether to trust a page before grounding on it. [Try the scanner free](/scanner)[Read API docs](https://docs.buildonto.dev/api/read) 0–100 Accuracy score per read <100 ms Cache-hit latency 1,000 Free reqs / month, forever 01 // Shared ground ### What both products do well. Before the differences, the overlap. Jina Reader is a good product and gets a lot right. So does Onto. Here's the honest shared baseline. Markdown01 HTML → clean Markdown Both strip nav and chrome, preserve semantic structure, and return text an LLM can ingest directly. The basic job is identical. JS rendering02 Handles dynamic pages Both render JavaScript-heavy SPAs without you operating a headless browser or proxy pool. Same single endpoint, different infrastructure. Free tier03 Real free usage, no card Both offer real free quotas — Jina via the unauthenticated reader, Onto via a 1,000 req/month forever tier on every API key. Managed04 No infra to run Both are managed APIs with edge caching and reasonable rate limits. Neither needs you to deploy crawlers, browsers, or scrapers yourself. 02 // Capability matrix ### Feature-by-feature. Em-dashes mean "not a current capability," not "intentionally missing." Onto Read API Jina Reader HTML → Markdown ✓Yes Yes AIO accuracy score (0–100) ✓Every response — Hallucination-risk flags ✓Per-field risk labels — Score insights & penalties ✓Traceable to structural causes — Site-side SDK (Serve) ✓@ontosdk/next, request-time inject — Official MCP server ✓@ontosdk/mcp — Auth model ✓Bearer token, per-user Optional API key Edge-cache latency ✓Sub-100 ms hit Origin-side cache Response determinism ✓Content-hashed Best-effort Pricing model ✓Subscriptions + credit packs Free + token-based paid Embedding integration — (use any embedder downstream) Yes (Jina embeddings) 03 // Where Onto extends the layer ### The scoring + safety layer Jina doesn't ship. Anyone can clean HTML. The interesting question is what arrives with the Markdown — the metadata your agent needs to decide whether to trust a page. 01 0–100 accuracy score Every read returns a subtractive score grading semantic clarity, structural richness, and content-negotiation health. Jina gives you Markdown; Onto tells you whether the Markdown is worth grounding on. 02 Per-field hallucination flags We surface specific fields the page describes ambiguously or contradicts itself on. Your agent can route low-confidence fields differently — refuse, fall back to a stronger model, or ask the user. 03 Official MCP server @ontosdk/mcp drops Onto's three tools (read\_url, score\_url, read\_and\_score) into Claude Code, Cursor, Cline, Zed, Continue. No HTTP layer needed if you live in an MCP host. 04 One engine across Read · Serve · Act The cleaning + scoring engine that powers reads also powers @ontosdk/next — site owners can opt in to feed agents their own pre-cleaned content with the same accuracy bar. Jina is read-only. 04 // Which to pick ### The honest decision matrix. A comparison page that only says "pick us" isn't a comparison. Here's when each one is actually the right call. Pick Onto if01 * ✓You're building an AI agent and need to know whether to trust a page before grounding on it. * ✓You want hallucination risk flagged at the field level, not handled post-hoc with a re-prompt. * ✓You're planning to ship the same content surface to your own users via the Serve SDK — one engine, one accuracy bar. * ✓You want an MCP server so the agent in Claude/Cursor/Cline can call read\_and\_score directly. Pick Jina Reader if02 * →You want zero-signup, no-auth Markdown extraction for quick experiments — Jina's unauthenticated r.jina.ai endpoint is unbeatable here. * →You're already in the Jina ecosystem (embeddings, rerankers) and want first-party integration. * →Your use case is straight HTML-to-Markdown for downstream processing — you don't need scoring or hallucination flags. * →You want token-priced usage rather than subscriptions + credit packs. 05 // Common questions ### What developers ask before switching. Can I migrate from Jina Reader to Onto?+ Yes — both endpoints accept a URL and return Markdown. The shape differs (Onto returns a JSON wrapper with `markdown`, `score`, `insights`, `hash`; Jina returns Markdown directly), but most integrations swap in under an hour. Set `Accept: text/markdown` on Onto's `/v1/read` if you want the same plain-text response Jina gives you. Is Jina free forever, like Onto's free tier?+ Jina's unauthenticated reader endpoint is genuinely free with rate limits; Jina's authenticated API has a generous free tier on the paid plan. Onto's free tier is 1,000 requests/month forever with no card. Honest: both are real free tiers; Jina's unauth flow is faster to start with, Onto's gives you scoring on every call. Does Onto offer embeddings like Jina?+ No. Onto stops at clean Markdown + a 0–100 accuracy score + hallucination flags. Embed the output with whatever embedder you prefer downstream — OpenAI, Voyage, Cohere, or Jina's own embeddings. The advantage of decoupling is you can swap embedders without re-running extraction. What's the AIO score actually grading?+ The score is _subtractive_: a page starts at 100 and loses points for specific structural problems — missing headings, schema not parseable, content-negotiation absent, JS-rendered content with no SSR fallback. Every penalty is traceable to a named cause. [Full methodology](/scoring). Is this comparison fair?+ We tried. Jina Reader is a good product and the unauth endpoint is genuinely best-in-class for quick experimentation. We're optimized for read + score for AI grounding; they're optimized for read + embed for retrieval. If you need both jobs, run them side by side on a few of your real URLs and let your own data decide. Try it on your URLs ### Run both on the same page. Let the data decide. The scanner is free. Drop any URL and get an AIO score in seconds — then run it through Jina Reader and compare the output side by side. [Open the scanner](/scanner)[// Or see pricing](/pricing)