Linked Papers

A lightweight, self-hosted web app for exploring academic paper reference graphs. Search for a paper and see an interactive graph of the papers it cites. Node size is proportional to citation count.

Features

• Search by paper title, DOI, or arXiv ID
• Interactive force-directed graph (vis-network)
• Node size based on citation count
• Click a node to see details; double-click to re-center the graph
• File-based JSON cache (survives container restarts)
• Works offline for previously cached graphs
• Uses OpenAlex for all paper data
• Shows only outgoing references (papers the seed paper cites)
• Dockerized

Data Source

• OpenAlex API: https://openalex.org/

OpenAlex is free. Anonymous usage has rate limits; if you hit them often, get a free API key and set it in a .env file (see below).

Quick Start

# (Optional) Add your OpenAlex API key
cp .env.example .env
# edit .env with your OA_API_KEY and OA_EMAIL

# Build and run
docker-compose up -d --build

# Open locally
# http://127.0.0.1:5000

Configuration

Edit docker-compose.yml to tune these environment variables:

Variable	Default	Description
CACHE_TTL_DAYS	30	Days before cached graph is refreshed
SEARCH_LIMIT	20	Number of search results, sorted by citation count
REFERENCE_LIMIT	100	Top N papers cited by the seed paper (outgoing)
OA_API_KEY	(from .env)	OpenAlex API key (higher rate limits)
OA_EMAIL	(from .env)	Email for OpenAlex polite pool (recommended)

Getting an API key (optional but recommended)

• OpenAlex: https://openalex.org/rest-api

Set it in .env and restart:

cp .env.example .env
# edit .env with your OA_API_KEY and OA_EMAIL
docker-compose up -d

Cache

Cached graphs are stored as JSON files in ./cache/. To clear the cache:

rm -f cache/*.json

You can also inspect the cache files directly — they are plain JSON.

Troubleshooting

503 from OpenAlex

OpenAlex has its rate limit and sends a 503 if exceeded. Set OA_API_KEY and OA_EMAIL for higher limits.

Offline Mode

If the APIs are unreachable but a cached graph exists, the app returns the cached graph automatically.

Useful Commands

# View logs
docker-compose logs -f

# Restart
docker-compose restart

# Stop
docker-compose down

# Rebuild after code changes
docker-compose up -d --build