Comparison
Nexus vs Galileo AI for Agent Observability
Galileo AI focuses on LLM evaluation — hallucination detection, fine-tuning data curation, and prompt regression testing. Nexus focuses on agent runtime observability. Here's when each tool is the right fit.
TL;DR
Choose Nexus if you…
- ✓ Need runtime trace visibility for live AI agents in production
- ✓ Want per-agent health cards, error rates, and alerting
- ✓ Want webhook and email alerts when agent error rates spike
- ✓ Need a simple $9/mo flat price with no evaluation quotas
Choose Galileo if you…
- ✓ Need systematic hallucination detection and quality scoring
- ✓ Are running fine-tuning workflows and need evaluation datasets
- ✓ Need prompt regression testing across model versions
- ✓ Your primary concern is LLM output quality, not runtime health
Feature Comparison
| Feature | Nexus | Galileo AI |
|---|---|---|
| Primary focus | Agent runtime observability | LLM evaluation and quality |
| Live agent tracing | ✓ Full span waterfall, per-agent view | Offline evaluation, not runtime traces |
| Hallucination detection | Not built-in | ✓ Core feature — automated scoring |
| Fine-tuning data curation | ✗ Not supported | ✓ Evaluation dataset export for fine-tuning |
| Per-agent health dashboard | ✓ Error rates, 7d trends, alerting | No agent-level health view |
| Webhook / email alerts | ✓ Included on Pro plan | Not available |
| Prompt regression testing | Not supported | ✓ Compare prompt versions systematically |
| Pricing | Free tier + $9/mo flat (Pro) | Enterprise pricing — contact sales |
| Setup time | 5 min — one API call to start tracing | Longer — requires eval dataset setup |
| Multi-framework support | ✓ LangChain, CrewAI, AG2, LangGraph, more | OpenAI / Anthropic focused |
The honest take
Galileo and Nexus address different phases of the AI development lifecycle. Galileo is a pre-production quality tool: you build evaluation datasets, score model outputs for hallucination and relevance, and use that signal to guide fine-tuning or prompt engineering decisions.
Nexus is a production monitoring tool: once your agent is live, you need to know which runs failed, why, and which agents are healthy. That's real-time trace data, per-agent error rates, and alerting when error rates spike — not offline evaluation scores.
Many teams use both: Galileo for pre-deployment quality gates, Nexus for post-deployment runtime health. They don't really compete — they sit at different points on the same pipeline. If you're only choosing one and your primary concern is "are my production agents working?", Nexus is the answer.
Galileo's pricing is enterprise — you'll need to contact sales. Nexus is $9/mo flat with a free tier and no sales call required. For indie developers and small teams, that difference alone often settles the decision.
Try Nexus free
Agent runtime observability. Free tier, no credit card required. Works with LangChain, CrewAI, LangGraph, AG2, and more.