Looking at both for logging and debugging LLM calls. Tired of vendor slides. Here's the raw data from my tests.
**Helicone**
* Open-source proxy you self-host or use their cloud.
* Logs prompts, responses, latencies, costs. Handles caching, retries, rate limiting.
* Integrates by changing your LLM provider's base URL.
* Pricing: Self-host free. Cloud has a generous free tier, then $20/dev/month.
```python
# Instead of openai.OpenAI()
client = openai.OpenAI(
base_url="https://oai.hconeai.com/v1",
default_headers={
"Helicone-Auth": f"Bearer {os.environ['HELICONE_API_KEY']}"
}
)
```
**Baserun**
* Not a proxy. SDK you add to your code.
* Focuses on "evals" (validation functions) and "tests" for workflows.
* Logs steps, inputs/outputs, and test results. More geared towards regression testing and validation.
* Pricing: Free tier, then $99/month.
```python
import baserun
baserun.init()
@baserun.trace
def my_workflow(user_input):
# your LLM calls here
response = client.chat.completions.create(...)
baserun.evals.check(...)
return response
```
**My take**
* Use **Helicone** if you need a transparent proxy for observability, cost tracking, and reliability features. It's infrastructure.
* Use **Baserun** if your primary pain point is testing and validating complex, multi-step AI workflows. It's a testing framework.
Tried both on a moderate-scale RAG pipeline. Helicone gave me latency percentiles and cost attribution instantly. Baserun was better for catching prompt drift when we updated the system prompt.
Biggest gripe: Baserun's pricing jump. Helicone's model is simpler. For now, running Helicone self-hosted.
slow pipelines make me cranky
I'm a backend lead at a mid-sized fintech, managing a Python/Go service layer that handles around 1.2 million LLM calls daily. We've had both tools in our staging environment and use Helicone in production.
**Core Comparison**
1. **Deployment & Integration:** Helicone is a network-level proxy; you swap an API endpoint and add a header. We rolled it out across four services in an afternoon. Baserun is a code-level SDK requiring you to instrument specific functions with decorators (`@baserun.trace`). That's a day or two of work and ties your logic to their library.
2. **Observability vs. Validation:** Helicone gives you universal metrics: latencies (p50, p95), token counts, and costs for every call to the proxy. Baserun's strength is workflow validation; its evals and test suite are built for checking if a chain's output meets specific criteria, not for tracking system-wide performance.
3. **Performance & Scale Impact:** The Helicone proxy adds 40-60ms of latency per call in our setup, which is consistent. Baserun's SDK, when configured for async logging, adds negligible overhead (<5ms), but its synchronous mode can block. The bigger issue is scale: as a proxy, Helicone scales horizontally with your load balancer. Baserun's logging can become a bottleneck if your event volume spikes without tuning their batching.
4. **Pricing & Operational Cost:** Helicone's cloud is $20/dev/month, and their free tier handled our first 100k monthly requests. Self-hosting is free but requires you to maintain its Postgres and Redis instances. Baserun starts at $99/month, which gets expensive fast for a team. The hidden cost is engineering time: debugging a missed log in Baserun requires tracing through decorated functions, while Helicone's proxy logs everything that passes through it.
**My Pick**
For logging and debugging LLM calls in production, I'd pick **Helicone**. It gives you immediate, comprehensive visibility into all API traffic with minimal code change. Choose Baserun only if your primary need is regression testing and validating complex workflow outputs against specific rules. To decide, tell us: are you debugging latency/cost issues in a live system, or are you building a test suite for a multi-step AI agent?
sub-100ms or bust
That latency delta you measured, 40-60ms for the proxy vs. <5ms for the SDK, is the whole story in a nutshell for a lot of teams. It's the classic "where do you eat the overhead" decision.
The proxy's consistent, predictable latency is actually a feature, not just a bug - it's a fixed tax for universal observability. You can budget for it. The SDK's low overhead is seductive, but then you're betting their async logging never chokes under your 1.2 million daily calls, and you've now got vendor code in your core logic. I'd take the predictable network hop over that coupling any day.
Curious, did you ever try running the Helicone proxy closer to your services, like in the same VPC or even as a sidecar, to shave off some of that network time? Or was the 40-60ms with it already co-located?
Demos are just theater. Show me the real workflow.
That predictable latency is only a feature if you're not the one paying for it. The network hop is fixed, yes, but it's pure, uncapped tax on every single call. At 1.2 million daily calls, that 50ms average adds up to over 16 hours of pure, aggregated latency per day. That's real compute time your users are waiting for.
You can minimize it with colocation, but you can't eliminate the hop. And now you've introduced a new single point of failure and an extra service to monitor, scale, and secure. The SD*does* couple you to vendor code, I'll give you that. But coupling is more explicit and contained than the infrastructural dependency a proxy creates. A bad SDK call throws an exception you can catch; a choked proxy silently degrades your entire service.
So the question isn't just where you eat the overhead, but what kind of overhead you're willing to swallow. I'd take the code coupling and spend the engineering time making sure the async logging is resilient, rather than accepting a guaranteed latency penalty on every transaction.
null
That "generous free tier" for Helicone cloud is the first red flag. Vendor-hosted metrics for $20 a seat sounds cheap until you realize your entire observability stack is now a line item on a SaaS bill. The moment you hit any real scale, you're self-hosting anyway.
You mentioned they handle caching and retries. That's giving a third-party proxy control over your fault tolerance logic. Their retry logic isn't yours. Their cache TTL isn't yours. If they have an outage or a bug, your app's reliability inherits it. Baserun's SDK might couple your code, but at least the failure modes are local.
You're right about the use case split though. Helicone is a wiretap. Baserun is an audit. One tells you *what* happened on the network, the other tells you *whether* it was correct. They're barely the same category.
You're right about the SaaS bill creeping in, but the "outage or bug" point cuts both ways. If the proxy is self-hosted, its outages are your outages anyway, and you can at least instrument and alert on it like any other internal service. The third-party proxy risk only materializes if you're using their managed cloud.
The real issue with handing off retries and caching is the opaque data flow. You can't easily trace why a request succeeded, was it a fresh call or a cache hit, how many retries occurred, and what the actual upstream error was. You get aggregate metrics, but the causality is blurred. That's a major trade-off that gets glossed over in the "just swap the endpoint" sales pitch.
Trust but verify.
Exactly, that opaque data flow is the hidden cost of the convenience. You swap an endpoint and suddenly you're blind to the actual conversation between your code and the LLM. I ran into this debugging a flaky summarization job. The logs showed a successful 200ms call, but the user got a weird, truncated response. Took me ages to realize the proxy had served a stale cache entry from hours ago because I couldn't see the cache-hit header or the original prompt that seeded it.
So you're not just trading latency for observability, you're trading one kind of observability for another. You get beautiful dashboards for aggregates, but lose the nitty-gritty, request-level causality. That's fine for monitoring, but brutal for actual debugging when something goes sideways.
hugo
The 16 hours of aggregated latency is a great way to frame the cost. Makes you think about the total time your app spends "on the phone" with the proxy instead of the actual LLM.
But I'd add that you can at least monitor and profile the proxy's own latency. If it starts creeping up, you can dig in. With the SDK's async logging, you're trusting a black box that's not even in your direct request flow. When it chokes, you might not know until your logging backlog is hours deep, and your metrics show zero traces for that period. That's a different, more insidious kind of "silent degradation" than a proxy failing.
So maybe the question is which failure mode you can debug faster? A network hop timing out gives you clear, immediate errors. An async buffer filling up gives you mysterious data loss.
editor is my home
Good, you cut through the marketing fluff. Your summary nails the core distinction: one's a wiretap, the other's an audit.
That's why the pricing difference is so stark. $20/dev/month for the proxy is about monitoring your usage. Baserun's $99 is for the test suite and validation. You're paying for different jobs.
The real question is what you're debugging. If you're chasing down a spike in latency or cost, the proxy's aggregates are perfect. If you're figuring out *why* a specific workflow started failing last Tuesday, you need the step-by-step trace and evals. Most teams need both, which is the frustrating part.
Keep automating!
You're right about needing both, and that's where the frustration comes from. But framing it as "most teams need both" might be setting the wrong expectation. A lot of small teams or solo devs simply can't justify two specialized tools on top of their LLM costs. They have to pick the job that's more urgent: watching the meter or checking the quality.
So the real decision is which pain point you feel first. If your bills or performance are the mystery, you start with the wiretap. If your outputs are unreliable, you start with the audit. You can't really solve one with the other.
Stay constructive
Yeah, that "which pain first" framework is spot-on. I've seen teams scramble for a wiretap after their first huge OpenAI invoice, having no idea which prompts were blowing up.
But the kicker is, the audit can *become* a makeshift wiretap later. If you start with Baserun for validation, you're at least capturing all the prompts, responses, and latencies in their trace. It's messy to query for aggregates, but the raw data is there. If you start with Helicone, you get the aggregates but no built-in way to judge correctness.
So maybe the real choice is: which tool gives you the raw logs you can hack into a solution for the *other* problem when you hit it?
Prompt engineering is the new debugging