LangSmith vs Opik in 2026 - Turnkey and Closed vs Cheap and Open

LangSmith and Opik sit at opposite ends of the same category. LangSmith is turnkey, closed, deeply wired to LangChain, and expensive at scale. Opik is open, framework-agnostic, self-hostable for free, and the cheapest managed cloud in the category. If you are comparing them, you are usually a LangSmith user staring at the trace bill, or a new team deciding whether the LangChain integration is worth the lock-in. Either way, the answer turns on two things: how deep you live in LangChain, and how much the meter scares you.

I have run both. Here is the honest split.

The short version

	LangSmith	Opik
License	Fully closed source	Apache-2.0 (OSI permissive)
Self-host	Enterprise only	Free, full features, no gates
Best for	LangChain and LangGraph apps	Cheapest cloud, permissive OSS
Starting price	$39/seat/mo	Free / $19/mo
Cost at scale	~$2,514/mo at 1M base traces	$5 per 100k spans over 100k
Eval standout	Align Evals (judge calibration)	LLM-judge, code metrics, Agent Optimizer
Backed by	LangChain ($1.25B valuation)	Comet (founded 2017, ~$63M raised)

LangSmith: the deepest LangChain tracing, at a price

LangSmith is the most turnkey observability you can point at a LangChain app. Add a callback and every chain, tool call and agent step shows up traced with zero extra work. Nothing touches it for depth on LangChain and LangGraph code, because nobody else ships LangChain. The eval side is strong too - Align Evals, its workflow for calibrating an LLM judge against human scores, is a genuinely useful capability most tools do not treat as first-class.

It is backed by a $1.25B company (roughly $260M raised), so survival is not the question. Value-for-money is.

Two things keep it hard to recommend broadly. The bill runs roughly $2,514/mo at 1M base traces on one seat, about 25x Langfuse for comparable volume, with base traces at $2.50 per 1,000 and extended at $5.00. And you cannot self-host your way out - LangSmith is fully closed source and self-hosting is Enterprise-only. It accepts OpenTelemetry as a receiver, so you are not forced onto the LangChain SDK, but the zero-config magic only appears when you use it. When LangChain cut its old free tier, Reddit threads pushed a visible wave of users toward self-hosted alternatives for exactly this reason.

Opik: open, cheap, and self-hosts without the catch

Opik is Comet’s open-source observability and eval platform, and it is the near-opposite of LangSmith on every axis that matters to a cost-sensitive team. The OSS build is Apache-2.0 - the most permissive license of the major platforms - and Comet states the self-hosted version ships the full feature set with unlimited spans, members and retention, and no feature gates. You keep everything when you self-host, and the per-trace cost disappears.

If you want managed, Opik’s Pro cloud is $19/mo for 100k spans - the cheapest paid tier of the major eval platforms, with $5 per additional 100k. It is also the fastest-growing project of its peers at roughly 20.8k GitHub stars, and the eval side is real: LLM-as-judge, code metrics, online evaluation, Guardrails and an Agent Optimizer.

The honest gotcha is per-seat pricing at scale. The recurring complaint is that seat costs climb as the team grows - the $19 headline is the small-team configuration. A few users also report occasional UI slowdown on very large projects. Neither undercuts the core value, but if you are a big team, model the seat cost before you commit to the cloud.

Where Langfuse fits

If you are leaving LangSmith on cost, Langfuse is the other default destination and worth weighing against Opik. It is MIT, self-hosts free with only three features gated, and runs about $101/mo at 1M events versus LangSmith’s roughly $2,514/mo. Against Opik, the trade is that Langfuse’s self-host is a heavier four-service stack (Postgres, ClickHouse, Redis, S3), while Opik’s self-host is more turnkey and its cloud is cheaper. We cover the full field in LangSmith alternatives and the pairing in Opik vs Langfuse.

LangSmith vs Opik: which should you pick?

• You live in LangChain and LangGraph and the bill does not scare you - LangSmith. The zero-config tracing is the deepest available for that stack, and Align Evals is a real reason to stay.
• You are cost-sensitive at production volume - Opik. $19/mo managed or free self-host, against LangSmith’s ~$2,514/mo at 1M traces, is not close.
• You need to self-host on your own infrastructure - Opik. LangSmith gates self-host behind an Enterprise sales call; Opik hands you the full-featured build under Apache-2.0.
• You are framework-agnostic and want out of any lock-in - Opik, which works across 60+ integrations rather than being deepest on one stack.
• You want the cheapest managed cloud specifically - Opik at $19/mo, the cheapest of the major platforms.
• You want a broader look before deciding - read best LLM observability tools and Opik alternatives.

Every price and date here was read from each vendor’s own materials on 26 July 2026. This category ships breaking changes monthly, so we re-verify every 30 days. The gap that decides most of these migrations - the roughly 25x between LangSmith and the open tools at 1M traces - has held for a while. If cost is why you are here, it is not close.