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Machine Learning · head to head

LlamaIndex vs Preact

LlamaIndex logo

LlamaIndex

Machine Learning

Data framework for LLM applications

From
Free
Rated
-
Full reviewWebsite
Preact logo

Preact

Web Development

3kB alternative to React with the same modern API

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: LlamaIndex the free LlamaCloud plan includes 10K credits and has no pay as you go option, so work stops when credits run out; Preact compatibility through preact/compat is good but not total, and some React libraries break in ways that are hard to diagnose
  • They diverge on capability: LlamaIndex covers Data connectors, Preact covers 3kB runtime.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which LlamaIndex and Preact actually diverge.

Attributes where LlamaIndex and Preact differ
AttributeLlamaIndexPreact
Pricing modelusage-basedOpen source, no licence fee
PlatformsLinux, Mac, WindowsWeb
CategoryMachine LearningWeb Development
Founded2022Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in LlamaIndex

  • Data connectors
  • Indexing
  • Query engine
  • RAG pipelines
  • Agents
  • OpenAI
  • Anthropic
  • Pinecone

Only in Preact

  • 3kB runtime
  • preact/compat
  • Same modern API
  • Fast rendering

What people use each for

The jobs each tool is most often brought in to do.

LlamaIndex

  • Parsing PDFs and complex documents into structured text for RAGnot Preact
  • Building retrieval augmented generation pipelines over private datanot Preact
  • Indexing and querying enterprise documents from an LLM applicationnot Preact

Preact

  • Embedded widgets that load inside someone else’s page and must stay smallnot LlamaIndex
  • Marketing and content sites where JavaScript payload affects Core Web Vitalsnot LlamaIndex
  • Applications targeting low-bandwidth or low-powered devicesnot LlamaIndex

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

LlamaIndex

  • The free LlamaCloud plan includes 10K credits and has no pay as you go option, so work stops when credits run out
  • Concurrent parse jobs are capped at 5 on Free and Starter, 20 on Pro and 100 on Enterprise
  • Pay as you go spend is capped at $500 per month on Starter and $5,000 per month on Pro
  • Enterprise SSO is Enterprise plan only
  • Volume discounts on credits and 5x higher rate limits are Enterprise only
  • SaaS or hybrid cloud deployment choice and a dedicated account manager are Enterprise only
  • Enterprise pricing is by quote with no published rate

Preact

  • Compatibility through preact/compat is good but not total, and some React libraries break in ways that are hard to diagnose
  • Behavioural differences from React exist in edge cases, particularly around event handling
  • A much smaller community, so unusual problems have fewer existing answers than React

Pricing, plan by plan

LlamaIndex

Free
  • FreeFree
    • 10K monthly credits
    • Basic parsing
    • 5 concurrent jobs
  • Starter$50/month
    • 40K credits + pay-as-you-go
    • Up to 400K credits
    • 5 concurrent jobs
  • Pro$500/month
    • 400K credits + limited-time bonus
    • 20 concurrent jobs
    • Priority Slack support
  • Enterprise$null/custom
    • Custom volume discounts
    • 5x higher rate limits
    • SSO

Preact

Free
  • PreactFree
    • Full library
    • Commercial use permitted
    • No usage limits

Which should you pick?

Choose LlamaIndex if

  • You need data connectors.
  • You want to start without paying.
  • You work on Linux, Mac, Windows.
  • You also want indexing.
LlamaIndex review

Choose Preact if

  • You need 3kb runtime.
  • You want to start without paying.
  • You also want preact/compat.
Preact review

Questions people ask

Is LlamaIndex or Preact better?
Neither clearly leads. LlamaIndex starts at Free and Preact at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, LlamaIndex or Preact?
LlamaIndex starts at Free and Preact at Free.
Does LlamaIndex or Preact run on more platforms?
LlamaIndex runs on Linux, Mac, Windows. Preact runs on Web.
Can I use LlamaIndex for free?
Both have a free tier, so you can try either at no cost before committing.
What is LlamaIndex best used for?
LlamaIndex is most often used for parsing pdfs and complex documents into structured text for rag, building retrieval augmented generation pipelines over private data, indexing and querying enterprise documents from an llm application. Of those, parsing pdfs and complex documents into structured text for rag and building retrieval augmented generation pipelines over private data are not what Preact is typically brought in for.
What can LlamaIndex do that Preact cannot?
LlamaIndex covers Data connectors, Indexing, Query engine, RAG pipelines. Preact covers 3kB runtime, preact/compat, Same modern API, Fast rendering.

Answered from the vendors’ own pages

LlamaIndex: How much does LlamaIndex (LlamaParse) cost?

LlamaIndex offers a Free plan with 10K monthly credits at $0/month. The Starter plan is $50/month for 40K credits plus pay-as-you-go overage up to 400K total. The Pro plan is $500/month for 400K credits. Credits are priced at 1,000 credits for $1.25.

Source
Preact: Is Preact free?

Yes, open source under the MIT licence.

LlamaIndex: Is LlamaIndex free?

Yes, LlamaIndex offers a free plan with 10K monthly credits, basic parsing, 5 concurrent jobs, and support for up to 100 users with no upfront payment required.

Source
Preact: Can I use React libraries with Preact?

Most, through the preact/compat layer. Compatibility is good but not complete, so libraries relying on React internals can break.

LlamaIndex: What are LlamaIndex's concurrent job limits?

The Free and Starter plans allow 5 concurrent jobs. The Pro plan increases this to 20 concurrent jobs. Enterprise plans offer custom configurations with 5x higher rate limits.

Source
Preact: Why choose Preact over React?

Bundle size, almost always. If payload is not a binding constraint, React’s ecosystem is usually the better trade.

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