Staxly

LangSmith vs Flagsmith

LLM observability, testing & evaluation — by LangChain
vs. Open-source feature flags + remote config — SaaS, private cloud, self-host

LangSmith websiteFlagsmith website

Pricing tiers

LangSmith

Developer (Free)
Free forever. 5,000 traces/month. 14-day retention. 1 seat. Basic evaluations.
Free
Plus
$39/seat/month. 10k base traces included ($2.50 per 1k overage). Full evaluations, custom dashboards, email support.
$39/mo
Enterprise
Custom. Self-host option, SSO, custom retention, dedicated support.
Custom
LangSmith website

Flagsmith

Free
$0. 50,000 API requests/mo. 1 team member. Unlimited flags. Community support.
Free
Self-hosted
$0 (OSS). Host yourself via Docker/K8s. Fair-source license (non-compete).
$0 base (usage-based)
Start-up
$40/mo. 1,000,000 API requests/mo. 3 team members. Standard support.
$40/mo
Scale-up
$200/mo. 5,000,000 API requests. 10 team members. Priority support + SLA.
$200/mo
Enterprise
Custom. Unlimited API requests, SSO, SAML, RBAC, audit logs, on-prem.
Custom
Flagsmith website

Free-tier quotas head-to-head

Comparing developer on LangSmith vs free on Flagsmith.

MetricLangSmithFlagsmith
No overlapping quota metrics for these tiers.

Features

LangSmith · 14 features

  • AlertsThreshold alerts on latency, cost, eval metrics.
  • Annotation QueuesHuman-review workflows for trace quality rating.
  • Custom DashboardsAggregate metrics dashboards per project/tag.
  • DatasetsCollect examples → use as eval sets or training data.
  • EvaluationsLLM-as-judge, embedding similarity, custom Python evaluators, offline batch eval
  • LangChain IntegrationAuto-trace any LangChain/LangGraph run with env var.
  • LangGraph IntegrationFirst-class trace + eval for LangGraph agents.
  • LLM TracingAutomatic trace every LLM call + tool call + chain step.
  • OpenTelemetry ExportExport traces as OTLP to Datadog/Honeycomb/etc.
  • PlaygroundTest prompts + models inline before deploying.
  • Prompt CanvasVisual prompt editor with live test + eval.
  • Prompt HubPublic + private prompt library with versioning.
  • Self-Hosted (Enterprise)Docker + k8s deployment in your infra.
  • Threads + SessionsGroup traces into conversational sessions.

Flagsmith · 14 features

  • A/B TestingMultivariate flag splits.
  • Audit LogFull history of flag changes.
  • Change RequestsApproval workflow for flag changes.
  • Edge APIGlobal low-latency flag eval.
  • Feature FlagsBoolean + multivariate + JSON flags.
  • Local EvaluationServer SDKs eval flags locally — no per-req API call.
  • Percentage RolloutsGradual traffic ramp.
  • Remote ConfigNon-boolean config values.
  • Role-Based AccessFine-grained permissions.
  • Scheduled FlagsTime-based flag changes.
  • SegmentsRule-based targeting.
  • Self-HostingDocker/Helm install.
  • SSO + SAMLEnterprise SSO.
  • WebhooksOutbound event streaming.

Developer interfaces

KindLangSmithFlagsmith
CLILangSmith CLIFlagsmith CLI
SDKlangsmith-js, langsmith-pythonflagsmith-android, flagsmith-go, flagsmith-ios, flagsmith-java, flagsmith-js (browser), flagsmith-nodejs, flagsmith-python, flagsmith-ruby
RESTLangSmith REST APIFlagsmith REST API
MCPLangSmith MCP
OTHERLangSmith DashboardFlagsmith Dashboard, Flagsmith Webhooks
Staxly is an independent catalog of developer platforms. Outbound links to LangSmith and Flagsmith are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.

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