Humanloop alternative | LangWatch
Real agents need more than single-turn evals.
Multi-turn, multi-tool, open source. Yours to extend.
Humanloop scores single input/output pairs through a closed platform. LangWatch is OpenTelemetry-native, simulates full multi-turn agent flows, and gives you the source code under Apache 2.0.
single-turn eval
input: refund query
output: refund flow
score: 0.84
looks fine? not the whole story.
multi-turn simulation
- turn-01: greet
- turn-02: classify
- turn-03: lookup
- turn-04: policy ❗
- turn-05: escalate
caught at turn-04
turns/run
12
tools called
4
open source
yes
How LangWatch compares to Humanloop.
Five things teams care about when picking a quality layer for agents. Each row shows what Humanloop ships today and what LangWatch gives you on day one.
| Capability | LangWatch | Humanloop |
|---|---|---|
| 01 | Multi-turn testing | Single-turn evaluation |
| Agent simulation suite | Traditional eval platform focused on single input/output pairs. Multi-step agent flows are not the core model. | |
| 02 | Source code & deploy | Proprietary SaaS |
| Open source platform | Closed-source platform with restricted customization and dependency on vendor-controlled infrastructure. | |
| 03 | Observability | Custom instrumentation |
| Native OpenTelemetry | Proprietary SDK integration required, limiting interoperability with existing observability tooling. | |
| 04 | Evaluator model | GUI-led workflows |
| Code + UI evaluators | Platform-centric workflows designed primarily for manual testing and GUI-based configuration. | |
| 05 | Red teaming, governance, and gateway | Prompt-CMS focused |
| Adversarial safety and security testing, an AI gateway for every model and key, and a governance layer with control over every agent in your org, plus quality-aware alerts on eval-score drops. | Humanloop centers on prompt management and evals. No built-in agent red teaming, AI gateway, or org-wide agent governance. |
Three reasons agent teams choose LangWatch.
- 6 turns · 1 caught
Test the whole agent, not the prompt. Multi-turn simulations exercise tools, state, and reasoning. The kinds of failures that pop in production show up here first.
No vendor lock-in
Self-hosted Apache 2.0 deployment removes platform discontinuation risk. Acquisition-proof, by design.Deep agent tracing and debugging
AI-powered Ask finds errors and anomalies for you, across flame charts, span lists, topology and graph views, waterfall traces with a full audit trail, and your own saved lenses.
“Single-turn evals shipped a polite agent that broke on call three. Multi-turn simulations caught it in seven minutes.”
Lead engineer· Voice AI agent team
94% regressions caught pre-prod
5 min time-to-first-eval
any frameworks supported
$0 cost to start
Evals are table stakes. Agent simulation is the bar.
Try LangWatch yourself or book time with an expert to help you get set up.