Migrating from LangSmith

If you are moving LangChain tracing off LangSmith, this page is the mechanical walkthrough: stop the LangSmith exporter, point your chains at the Tracelane gateway, and (optionally) port your @traceable spans to the OpenTelemetry API. We do not restate LangSmith’s feature set here. It is an actively developed product — check what your plan covers against LangSmith’s own documentation rather than trusting our summary of someone else’s product. Below is what Tracelane brings, so you can compare it yourself.

What Tracelane gives you

Capability	Tracelane
Framework adapters	18+ `instrument_*` adapters (OpenAI, Anthropic, LangChain, LangGraph, CrewAI, AutoGen, MCP, …)
LLM gateway / BYOK	205 providers, 0 % markup on your provider keys
Inline guardrails	Heuristic rails at the gateway, verdicts written to the ledger. The predictive layer is observe-first by default — a `Block` is recorded and the request still proceeds unless enforcement is explicitly enabled
Tamper-evident audit log	Hash chain + Merkle + Ed25519 per-tenant signing (live); resolved Sigstore Rekor v2 inclusion proof on anchored batches (best-effort); universal per-run anchoring on the roadmap
Prompt versioning + gates	Prompt promotion live; rollback is EWMA drift on metrics you post, not autonomous; eval gating live — a promotion without a passing run returns `409` unless you record an attributed override
Time-travel replay	Read-only re-render; cross-model re-execution is on the roadmap
Self-hostable	Apache 2.0, single-node Docker Compose (`infra/self-host/docker-compose.yml`). No Helm chart is published

Step 1 — Install the SDK

pip install tracelane

Step 2 — Replace the LangSmith init

Before:

from langsmith import Client
client = Client()
# LangSmith tracing wired via environment:
# LANGCHAIN_TRACING_V2=true
# LANGCHAIN_API_KEY=ls__...

After: Tracelane captures your LangChain traces by routing the calls through the gateway (next step) — there is no tracing env var to set, and auto_instrument() deliberately does not touch LangChain (graphs and chains are user-constructed, so there is no default object to wrap). If you want SDK-side spans in addition to the gateway’s, call instrument_langchain(client) yourself after you build the client. Otherwise just set your key:

export TRACELANE_API_KEY=tlane_...

Remove LANGCHAIN_TRACING_V2, LANGCHAIN_API_KEY, and LANGSMITH_PROJECT from your environment.

Step 3 — Point your LangChain clients at the gateway

The Tracelane gateway is OpenAI-compatible. Point LangChain’s ChatOpenAI at it — including for Anthropic models. The gateway also serves native /v1/messages; this example uses the OpenAI-compatible route and routes by model prefix.

from langchain_openai import ChatOpenAI

# OpenAI-compatible providers
llm = ChatOpenAI(
    model="gpt-4o",
    base_url="https://gateway.tracelane.dev/v1",
    api_key="tlane_...",  # Tracelane resolves your provider key via BYOK
)

# Anthropic models — same endpoint, the model prefix selects the provider
claude = ChatOpenAI(
    model="claude-sonnet-4-6",
    base_url="https://gateway.tracelane.dev/v1",
    api_key="tlane_...",
)

Your LCEL chains, agents, and tools continue to work unchanged.

Step 4 — (Optional) Remove the LangSmith SDK

pip uninstall langsmith

If you used @traceable decorators for custom spans, replace with Tracelane’s OTel-based custom span API:

# LangSmith
from langsmith import traceable

@traceable
def my_function(x):
    ...

# Tracelane — standard OpenTelemetry API
from opentelemetry import trace

tracer = trace.get_tracer("my-app")
with tracer.start_as_current_span("my_function") as span:
    span.set_attribute("input", x)
    ...

Migrating existing LangSmith traces

There is no trace import path today. Tracelane ships no LangSmith importer, and the two importers it does ship — tlane import-helicone and tlane import-litellm — translate configuration, not trace history. Nothing in Tracelane ingests a LangSmith export, and there is no imported tag on traces. Plan for a cut-over rather than a backfill: keep your LangSmith history where it is for as long as you need to read it, and let Tracelane accumulate from the moment you point your chains at the gateway. If a historical import matters to your migration, tell us — it is not built.

Competitor details verified as of 2026-08-26 against public documentation and public repositories. Where a capability is marked absent, we found none documented at that date — not that the vendor lacks it. If anything here is inaccurate, please open an issue.

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Migrating from LangSmith

What Tracelane gives you

Step 1 — Install the SDK

Step 2 — Replace the LangSmith init

Step 3 — Point your LangChain clients at the gateway

Step 4 — (Optional) Remove the LangSmith SDK

Migrating existing LangSmith traces

​What Tracelane gives you

​Step 1 — Install the SDK

​Step 2 — Replace the LangSmith init

​Step 3 — Point your LangChain clients at the gateway

​Step 4 — (Optional) Remove the LangSmith SDK

​Migrating existing LangSmith traces

​Related

What Tracelane gives you

Step 1 — Install the SDK

Step 2 — Replace the LangSmith init

Step 3 — Point your LangChain clients at the gateway

Step 4 — (Optional) Remove the LangSmith SDK

Migrating existing LangSmith traces

Related