HotMem

A local-first memory sidecar for agent applications. One SQLite DB. One port: 8711.

HotMem provides fast, queryable working memory with hybrid vector + keyword search. Store facts, retrieve them ranked, and get back LLM-ready message objects you can stitch directly into prompts.

Supports Python 3.11, 3.12, 3.13, and 3.14.

Install

pip install hotmem
# or
uv pip install hotmem

Quick Start

# Start with a mount directory (portable memory)
hotmem serve --mount ./hotmem

# Or just start (uses temp DB)
hotmem serve

CLI

hotmem serve --port 8711 --mount ./data/hotmem
hotmem serve --db ./my.sqlite
hotmem hydrate --file swap.jsonl --db ./my.sqlite
hotmem hydrate --file swap.jsonl.gz --db ./my.sqlite
hotmem snapshot --file swap.jsonl --db ./my.sqlite
hotmem status

API

All endpoints under /v1. Default: http://127.0.0.1:8711

GET /v1/health

{"status": "ok", "memory_count": 42, "db_path": "...", "uptime_s": 120.5}

POST /v1/add

{"identifier": "vendor_x", "fact": "Invoice total was $5000", "importance": 0.8}

POST /v1/search

{"query": "duplicate invoice risk", "top_k": 5, "max_chars": 1500}

Returns ranked message objects ready for LLM stitching:

{
  "memories": [
    {"role": "system", "content": "...", "memory_id": "...", "identifier": "...", "score": 0.87}
  ],
  "count": 5,
  "trace_ms": 2.1
}

POST /v1/hydrate

{"file": "swap.jsonl"}

POST /v1/snapshot

{"file": "swap.jsonl"}

Python Client

from hotmem.client import HotMemClient

with HotMemClient("http://127.0.0.1:8711") as client:
    client.add("vendor_x", "Invoice total $5000", importance=0.8)

    memories = client.search("duplicate invoice risk", top_k=5, max_chars=1500)

    # memories are LLM-ready message objects
    messages = memories + [{"role": "user", "content": "Analyze this vendor."}]

Ecosystem

HotMem core stays zero-dep. Framework adapters live in adapters/, each a separate pip-installable package wrapping HotMemClient:

The hotmem-hermes adapter is the deep integration: HotMem implements the Hermes Memory Provider Plugin interface, so Hermes calls into HotMem at every lifecycle point automatically (prefetch, sync, memory-write mirroring, pre-compress extraction, session-end snapshot).

A typed TypeScript client (npm install hotmem) lives in ts/ — zero-dependency, works in Node 18+, Deno, Bun, and edge runtimes.

Mounting

Any directory can be a HotMem mount. The mount contains:

• hotmem.sqlite - the database
• swap.jsonl - portable JSONL backup
• manifest.json - mount metadata

Plain .jsonl is the canonical portable swap format. HotMem can also hydrate from and snapshot to .jsonl.gz for compressed archives.

hotmem serve --mount /mnt/usb/hotmem     # portable memory on USB
hotmem serve --mount ./data/hotmem        # local project memory

Development

uv sync                          # install deps
uv run pytest                    # run tests
uv run ruff check src/ tests/    # lint
uv run ruff format src/ tests/   # format
uv build                         # build wheel

Architecture

Each source module is self-contained with a docstring header describing its purpose and interface:

Every operation emits structured JSON traces to stderr with component tags:

hotmem serve --mount ./data 2>&1 | grep '"component": "search"'

Contributing

See CONTRIBUTING.md for development setup and guidelines.

License

MIT - see LICENSE.