LangSmith vs. Helicone: Best Open-Source Tool for LLM Observability
Deep Dive: LangSmith vs. Helicone
What Makes Helicone Different?
1. Helicone is Open-Source
Helicone is fully open-source and free to start. Companies can also self-host Helicone within their infrastructure. This ensures that you have full control over the application, flexibility, and customization tailored to specific business needs.
LangSmith is a closed-source solution, which means you're dependent on their development roadmap and pricing structure.
2. Ease of Integration
Developers often choose Helicone for our simple proxy setup. Simply by changing the base URL, you can start logging everything with any providers.
https://oai.helicone.ai/v1 # new baseURL
https://api.openai.com/v1 # old baseURL
Being a proxy, Helicone offers caching, prompt threat detection, key vault, rate limiting, and other useful gateway features.
However, if you don't want to place Helicone in your critical path, you can use our async logging method.
Latency Impact & Reliability 💡
Helicone is built on the edge using Cloudflare Workers to minimize time to response. This adds only ~50 ms for about 95% of the world's Internet-connected population. We're also proud of our 99.99% uptime in the last year.
3. Scalable Usage-Based Pricing
Helicone is more cost-effective than LangSmith for two reasons.
First, we operate on a volumetric pricing model that gets cheaper the more requests you have. Second, our paid tier starts at $20/seat/month, which gets you access to all features in Helicone, compared to $39/seat/month for LangSmith. Our seat-based pricing caps at $200/mo for fast-growing teams needing unlimited seats.
Here's how the pricing scales between Helicone and LangSmith:
| Logs per month | Helicone | LangSmith |
|---|---|---|
| 10,000 logs | Free | Free |
| 25,000 logs | $24.00 | $7.50 |
| 50,000 logs | $44.00 | $20.00 |
| 100,000 logs | $61.50 | $45.00 |
| 2,000,000 logs | $631.50 🟢 | $995.00 🔴 |
| 15,000,000 logs | $2,321.50 🟢 | $7,495.00 🔴 |
Comparing Helicone and LangSmith
As a platform that focuses on optimizing your entire LLM lifecycle, Helicone isn't just a great alternative to LangSmith. It also outperforms in scalability and reliability compared to tools like Langfuse and Portkey.
| Helicone | LangSmith | |
|---|---|---|
| Best For | Teams looking for a holistic, user-friendly observability solution | Teams integrated with LangChain ecosystem |
| Pricing | Starting at $20/user/month. Free trial and multiple tiers available |
Starting at $39/user/month. Limited free plan, multiple tiers available |
| Integration | Proxy-based (popular with developers) or async SDK options | Async SDK option only |
| Strengths | Easy setup, real-time observability features like Sessions, intuitive UI, supports any LLM provider | Deep workflow tracing for lang-products, comprehensive evaluation tools |
| Drawbacks | No built-in support for automatically scoring requests and experiments | Complex for simple tasks, layers of abstraction. Mixed opinions about production readiness, especially among experienced engineers. |
LLM Observability and Monitoring
| Feature | Helicone | LangSmith |
|---|---|---|
| Open-Source | ✅ | ❌ |
| Self-Hosting Ability to deploy on your own infrastructure |
Highly flexible deployment options due to open-source nature | Only available to enterprise users |
| Real-Time Observability Reflect updates instantly |
✅ See real-time updates on the dashboard as your agent is running |
❌ No real-time dashboard updates due to caching mechanism |
| Built-in Caching Cache common responses to reduce costs |
✅ | ❌ |
| Prompt Management Tools to version, test, and optimize prompts |
✅ | ✅ |
| LLM Workflow Tracing Track complex multi-step or agentic workflows |
✅ | ✅ |
| Experimentation Tools to test and compare different approaches |
✅ | ✅ |
| User Tracking Monitoring usage patterns by individual users |
✅ | 🟠 Basic user tracking |
| Security Features Key vault, rate limiting, threat detection |
✅ | 🟠 Basic security features |
| Supported LLMs Range of LLM providers compatible with the tool |
✅ Wide provider support |
🟠 Fewer models, optimized for LangChain ecosystem |
| User Support Discord support, chat, email, dedicated Slack for Enterprise |
✅ | ✅ |
Security, Compliance, Privacy
| Feature | Helicone | LangSmith |
|---|---|---|
| Data Retention Control how long data is stored |
1 month (Free) 3 months (Pro/Team) Forever (Enterprise) |
From 14 to 400 days (longer retention costs more) |
| API Key Management Securely store and manage provider credentials |
✅ | ✅ |
| Rate Limiting Prevent excessive usage and manage costs |
✅ | ❌ |
| Threat Detection Identify prompt injection and other security risks |
✅ | ❌ |
| Data Protection Control sensitive data logging/selective logging |
✅ | ✅ |
| HIPAA-Compliant Support for healthcare data privacy requirements |
✅ | ✅ |
| GDPR-Compliant Compliance with EU data protection standards |
✅ | ✅ |
| SOC 2 Certified Audited security and data handling practices |
✅ | ✅ |
Self-Hosting and Deployment Options
| Option | Helicone | LangSmith |
|---|---|---|
| Manual Installation Direct installation on servers |
✅ | ❌ |
| Kubernetes Container orchestration deployment. Helm charts available |
✅ | ✅ |
| Docker Compose Multi-container deployment |
✅ | ✅ |
| External Databases Connection to existing database systems |
✅ | ✅ |
| Licensing Licensing model for self-hosting |
✅ No license required |
✅ Enterprise license required |
UI Comparison: Helicone vs LangSmith
We believe that observability should be simple and intuitive at Helicone, that's why we designed our platform to be easy to use and understand. It's reflected in both our UI and workflow that are designed to make you more productive as a developer.
Integration Example
Helicone's proxy integration requires minimal code changes. Here's an example of integration with OpenAI:
import OpenAI from "openai";
const openai = new OpenAI({
apiKey: OPENAI_API_KEY,
baseURL: "https://oai.helicone.ai/v1",
defaultHeaders: { "Helicone-Auth": `Bearer ${HELICONE_API_KEY}` }
});
Which platform should you choose?
We hear our customers say that their experience of monitoring LLM application in Helicone is intuitive and integrates well into any LLM observability tech stack. LangSmith is a great tool, and there are some things we would recommend them over Helicone for, such as if you're an enterprise that is in the LangChain ecosystem.
Frequently Asked Questions
How hard is it to add Helicone or LangSmith to my existing app?
Helicone can be added by changing a single line of code (for the proxy approach) or using their SDK for background async logging. LangSmith requires adding decorators to your functions and using their SDK throughout your code.
Will these tools help me save money on my LLM costs?
Helicone has built-in caching that can significantly reduce costs by reusing responses for similar requests. LangSmith doesn't have any features particularly geared towards cost saving besides basic cost tracking.
Can I host these tools on my own servers?
Yes, both offer self-hosting. Helicone gives you more options (manual setup, Kubernetes, Docker, cloud deployment) and can be hosted for free, while LangSmith focuses on Kubernetes and Docker and requires an Enterprise subscription.