Arcana
Native RAG for Elixir/Phoenix with agentic loops and GraphRAG
Arcana is a standout RAG library for Elixir/Phoenix developers, offering deep OTP integration, three operation modes (advanced, modular, agentic), and built-in GraphRAG. It's free and open-source, with local-first embeddings via Bumblebee and support for cloud LLMs. However, it's strictly for Elixir projects—non-Elixir teams should look at alternatives like LangChain or Haystack. If you're on the BEAM, Arcana is the most native and capable choice for adding AI features.
Verified 15d ago · liveness 64/100 · cite: rightaichoice.com/tools/arcana
- Elixir developers wanting AI search/Q&A inside Phoenix apps
- Teams wanting RAG without extra services
- Projects needing agentic workflows inside OTP
- Ecto/PostgreSQL projects seeking a native AI layer
- Non-Elixir projects
- Beginners uncomfortable with Elixir/OTP
- Teams needing a hosted, no-code RAG solution
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Skip Arcana if you are not building in Elixir/Phoenix, if you need a hosted no-code RAG solution, or if your data lives outside PostgreSQL/pgvector.
Deploying Arcana in production requires you to run your own Phoenix app, PostgreSQL, and vector index—there is no managed service, so you pay for your own infrastructure.
Arcana is free and open-source, making it the cheapest RAG option for Elixir teams—no per-token or per-seat fees. Compared to Python-based libraries like LangChain, which may have paid tiers, Arcana is completely free, but you must bring your own infrastructure and LLM API keys.
In short
Arcana — Native RAG for Elixir/Phoenix with agentic loops and GraphRAG. Best for Elixir developers wanting AI search/Q&A inside Phoenix apps, Teams wanting RAG without extra services, Projects needing agentic workflows inside OTP. Free to use.
What people actually say about Arcana — is it worth it?
We scanned public community sources for Arcana on Jul 3, 2026 and could not establish that the discussion we found is about this tool rather than something else sharing its name. Our own analysis of that scan says the posts were off-subject. Rather than publish a sentiment score built on the wrong subject, we publish nothing here and re-run the scan.
Viability Score
How well maintained and how widely used is Arcana? Built from what the vendor actually publishes (docs, changelog, tutorials, integrations, pricing), whether the site is live, and how much real users discuss it. How we calculate this
Last calculated: September 2026
How we score →Key Features
- Advanced RAG with query rewriting and hybrid search
- Modular RAG via composable pipeline steps
- Agentic RAG with runtime tool selection
- GraphRAG with Leiden community detection
- Hybrid search (semantic + fulltext) with RRF fusion
- Cross-encoder reranking via Bumblebee
- Local embeddings via Bumblebee (EXLA/Torchx)
- Cloud LLM support (OpenAI, Anthropic, Z.ai)
- Streaming support for real-time responses
- Source citation with NLI hallucination check
- LiveView monitoring dashboard
- Telemetry events for pipeline steps
- Pluggable behaviours (chunker, embedder, searcher, etc.)
- Declarative configuration via mix igniter.install
- Self-correcting search and answer modes
About Arcana
Arcana is an embeddable Retrieval-Augmented Generation (RAG) library built natively for Elixir and Phoenix applications, leveraging the BEAM ecosystem and your existing Ecto repo with PostgreSQL and pgvector. It provides three modes of operation: Advanced RAG via Arcana.search/2 and Arcana.ask/2 with default query rewriting, hybrid search, and cross-encoder reranking; Modular RAG via Arcana.Pipeline for composing custom retrieval steps; and Agentic RAG via Arcana.Loop where the LLM picks tools like search, answer, or give_up at runtime. Arcana also ships GraphRAG with community detection (Leiden) and fusion with vector search. All processing runs inside your OTP supervision tree—no separate services needed. Built for Elixir developers who want AI features without leaving the BEAM, Arcana offers local-first embeddings via Bumblebee and optional cloud LLMs (OpenAI, Anthropic, Z.ai). It includes a LiveView dashboard for monitoring and debugging, extensive telemetry, and evaluation tooling. Unlike Python-based RAG libraries that require HTTP wrappers, Arcana runs as a native OTP library with low latency and full data control.
Behind the Verdict
Arcana excels because it treats RAG as a first-class citizen inside the BEAM, not as an external service. The three operation modes give you a clear path from a simple search to a fully agentic loop, and the modular pipeline lets you swap components (chunker, embedder, searcher) via custom behaviours. The built-in LiveView dashboard is a major plus for debugging, and the NLI hallucination check adds a layer of trust. However, the learning curve is real: you need to be comfortable with Elixir, OTP, and Ecto. The lack of a hosted version means you manage your own infrastructure, and the library is tightly coupled to PostgreSQL/pgvector—if you're using another database, it's a dead end. For teams already on the BEAM, Arcana delivers unmatched integration and performance. For others, it's a non-starter. Compared to Python-centric RAG frameworks, Arcana is more performant and private, but less portable.
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Real-world workflow fit
Concrete scenarios for the personas Arcana actually fits — and what changes day-one when you adopt it.
You want to let users search posts by meaning, not just keywords.
Outcome: Install Arcana, add Ecto schema with pgvector, use Arcana.search/2 with hybrid search to return relevant posts, and display results in a LiveView component.
You need answers that cite sources and reduce hallucinations.
Outcome: Use Arcana.ask/2 with source citation and NLI hallucination check to provide trustworthy answers, and monitor performance via the LiveView dashboard.
You want the AI to decide whether to search, answer, or hand off to a human.
Outcome: Configure Arcana.Loop with tools like search and give_up, enabling the LLM to triage queries and escalate when confidence is low.
Use Cases
- Build a Q&A bot over your Elixir app's documentation and error logs
- Create semantic search for a Phoenix forum or knowledge base
- Automate customer support replies with agentic RAG pipelines
- Enable private, self-hosted AI research assistant for internal documents
- Add source-cited answer generation to any Phoenix LiveView dashboard
Models Under the Hood
as of 2026-09-08
Limitations
- Arcana is tied to the Elixir ecosystem, so non-Elixir projects cannot use it.
- The free open-source version lacks official support SLAs.
- Some advanced integrations (e.g., specific vector DBs) may require additional setup or paid modules in the future (currently all open source).
as of 2026-08-24
Verification history
We have re-verified Arcana 7 times since . Each pass re-reads the vendor's own pages and re-checks every listed field against that evidence; passes where nothing had changed are marked as such.
- — re-checked, vendor evidence unchanged
- — re-checked, vendor evidence unchanged
- — re-checked, vendor evidence unchanged
- — re-checked, vendor evidence unchanged
- — re-checked, vendor evidence unchanged
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
Showing the 6 most recent of 7 verification passes.
Free to cite with attribution — this page re-verifies continuously.
12-month cost
Project the real annual outlay, including the implied monthly cost when only an annual tier is published.
Vendor list price only. Add-on usage, seat overages, and contract minimums are surfaced under Hidden costs & gotchas.
Plans compared
For each published Arcana tier: who it actually fits, and what it adds vs. the previous tier. Cross-reference the cost calculator above for projected annual outlay.
Open Source
$0
Ideal for
Elixir developers and teams who want a free, self-hosted RAG library and are comfortable managing their own infrastructure and LLM API keys.
What this tier adds
This is the only tier—free and fully open source, with all features included and no paid upgrades.
Where the pricing makes sense
The company stage and team size where Arcana's pricing actually pencils out — and where peers do it cheaper.
Arcana is free and open-source, making it the cheapest RAG option for Elixir teams—no per-token or per-seat fees. Compared to Python-based libraries like LangChain, which may have paid tiers, Arcana is completely free, but you must bring your own infrastructure and LLM API keys.
Setup time & first value
How long it actually takes to get something useful out of Arcana — broken out by persona, not the marketing-page minute.
For an experienced Elixir developer, you can install Arcana and run a basic search within an afternoon (3-4 hours). Setting up agentic loops and GraphRAG may take a few days to tune. Beginners unfamiliar with OTP should budget extra time for learning the ecosystem.
Switching to or from Arcana
How to bring data in from common predecessors and how to get it back out — written for the switcher, not the buyer.
- →From LangChain (Elixir): Rewrite your pipeline using Arcana.Pipeline, swap Python dependencies for Elixir behaviours, and reuse existing Ecto schemas.
- ↗To Haystack: Export your indexed documents and re-index using Haystack's document store, then rewrite queries in Python.
Integrations
Resources & Guides
Tutorials & Learning
YouTube returned 6 videos for “Arcana”, and we withheld 6: 6 could not be judged, because “Arcana” is a single word that other videos use for other things. We are showing none, because we could not prove any of them are about Arcana.
Official links
Featured Head-to-Head Comparisons
Arcana vs Spider Cloud
Choose Spider Cloud if you need fast, low-cost web crawling and scraping with AI-powered extraction for any stack. Choose Arcana if you're building RAG inside an Elixir/Phoenix project and want a pure Elixir solution with no external service dependency.
Arcana vs Voyage Ai
For Elixir developers wanting an all-in-one, embeddable RAG solution without leaving the BEAM, Arcana is a no-brainer: free, open-source, and deeply integrated with Phoenix and Ecto. But for enterprises needing top-tier retrieval accuracy on specialized domains like finance or legal, Voyage AI's domain-tuned models and low-dimensional embeddings justify its contact-based pricing—especially with the new Voyage 4 series on the horizon. Choose based on your tech stack and need for domain specificity.
Arcana vs Temporal Ai
Temporal AI is the clear winner for teams needing reliable, fault-tolerant orchestration of AI agents and microservices across multiple languages, with strong support for human-in-the-loop and long-running workflows. Arcana is a niche but excellent choice for Elixir developers seeking to add RAG capabilities to their Phoenix apps without external dependencies. Choose Temporal for multi-language, mission-critical workflows; choose Arcana only if you're deep in the BEAM ecosystem.
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Frequently Asked Questions
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