Antfly vs pgvector
Open-source vector similarity search for Postgres
Feature Comparison
| Feature |  Antfly | pgvector |
|---|---|---|
| Price | ||
| Price | $ Open source (Apache-2.0), self-hosted | $ Free extension (PostgreSQL License); hosting varies |
| Search | ||
| Vector Search | Native Built-in vector engine with hybrid search | Native HNSW and IVFFlat indexes; halfvec, sparsevec, binary quantization, iterative scans for filtering |
| Full-Text Search | Native BM25 + semantic hybrid search | Native Built-in tsvector/tsquery; ts_rank is not BM25 (BM25 via pg_search or VectorChord-bm25 extensions) |
| Hybrid Search | Native Unified BM25 + vector scoring in a single query | Partial Hand-written SQL fusing tsvector and vector results, such as reciprocal rank fusion |
| Inference Models | ||
| Model Execution | Native Antfly Inference runs embedders, rerankers, chunkers locally | None None in pgvector; embeddings come from outside, or from the PostgresML extension |
| Re-ranking | Native Built-in cross-encoder reranking via Antfly Inference | None No native reranking |
| End-to-End RAG | Native Ingest, embed, store, retrieve, rerank, generate | None Retrieval only; embedding, reranking, and generation run elsewhere |
| Modalities | ||
| Text | Native Built-in text embeddings via Antfly Inference | Partial Stores text vectors; requires external embedding |
| Image | Native CLIP image embeddings via Antfly Inference | None No native image support |
| Audio | Native Audio embeddings via Antfly Inference | None No native audio support |
| Video | Native Video frame embeddings via Antfly Inference | None No native video support |
Native PDF chunking and embedding via Antfly Inference | None No native PDF support | |
| Storage | ||
| Structured Data / ACID | Native Full document store with ACID transactions | Native Full relational database with ACID transactions |
| Distributed Clusters | None No multi-node clusters; a standalone server with an optional hot standby | Partial Relies on Citus or manual partitioning for distribution |
| Multi-Tenancy | Native Namespace-level tenant isolation | Partial Schema or row-level security based |
| Hosting | ||
| Self-Hosted | Native A Lite file or a standalone server | Native Self-hosted anywhere PostgreSQL runs |
| Cloud-Hosted | Native Antfly Cloud, from $20/mo, first year free | Native Available on RDS, Supabase, Neon, and others |
| Operations | ||
| Operational Simplicity | Native Single binary, zero-config standalone mode | Partial Standard PostgreSQL administration applies |
Why Antfly
- Antfly runs on top of Postgres, not instead of it: built-in CDC replication streams your tables into the retrieval layer
- Built-in ML inference eliminates external embedding API costs
- Hybrid BM25 + vector retrieval with reranking and pruning, no hand-rolled SQL
- pgvector stores and matches vectors; Antfly adds the judgment layer: ranking, pruning, and learning from use
- Keep Postgres as your system of record; add the retrieval agents need
Pricing
Antfly
Free and open source (Apache-2.0) to self-host. Antfly Cloud from $20/mo, first year free.
pgvector
Free extension. PostgreSQL hosting varies; RDS from ~$15/mo, Supabase free tier or Pro from $25/mo.
pgvector itself is free; the external embedding, reranking, and orchestration services around it are the cost that adds up.
Deep Dive
pgvector brings vector similarity search to PostgreSQL, and if your team runs Postgres, you should probably have it. It keeps vectors next to your data, costs nothing to install, and is well maintained.
The question isn't pgvector or Antfly, because they sit at different layers. Postgres is your system of record, and pgvector gives it vector storage and similarity matching. What it doesn't give you is the rest of retrieval: embedding generation, hybrid fusion, cross-encoder reranking, score-based pruning, and multimodal indexing still come from external services and hand-crafted SQL.
Antfly sits on top of Postgres rather than replacing it. Built-in CDC replication streams your tables into a retrieval layer that adds hybrid BM25 + vector ranking, local ML inference, reranking, and pruning, and gets sharper with use. Keep your Postgres. Add retrieval. See the PostgreSQL Replication guide for the setup.