Setup
API Keys & Registration
BYOK setup for LLM providers and 51 knowledge sources. Verified July 2026.
c4reqber is free (AGPL-3.0) — you only pay upstream APIs. Minimum: one OpenRouter key. Add science keys to unlock full MultiSourceSearcher throughput.
Required
LLM providers (optional)
Search APIs
Scientific sources (recommended)
Manual approval
No registration needed
Add to .env
cp .env.example .env
# Minimum
export OPENROUTER_API_KEY=""
# Recommended for literature at scale
export NCBI_API_KEY=""
export NCBI_EMAIL="you@institution.edu"
export CORE_API_KEY=""
export TAVILY_API_KEY="" Copy .env.example → .env. Never commit secrets. Verify: python3 tools/check_keys.py