Staxly

LangSmith vs Mailgun

LLM observability, testing & evaluation — by LangChain
vs. Email API for developers with deep deliverability tooling

LangSmith websiteMailgun 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

Mailgun

Free
100 emails/day. 1 custom domain, 1-day log retention, 1 inbound route. No credit card.
Free
Basic
$15/month. 10,000 emails/month, no daily limit, 5 inbound routes.
$15/mo
Foundation
$35/month (1st month free). 50,000 emails/month, 1,000 custom domains, 5-day retention.
$35/mo
Scale
$90/month. 100,000 emails/month, SAML SSO, 5,000 email validations, dedicated IP pools, 30-day retention.
$90/mo
Enterprise
Custom. Deliverability services, managed onboarding.
Custom
Mailgun website

Free-tier quotas head-to-head

Comparing developer on LangSmith vs free on Mailgun.

MetricLangSmithMailgun
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.

Mailgun · 14 features

  • Batch SendingSend up to 1,000 recipients per API call via recipient variables.
  • Dedicated IPsIP pools with auto warmup. Scale+ tier.
  • Deliverability SuiteInbox placement testing, DMARC reporting, seed lists.
  • Email LogsSearchable log of all send attempts + events.
  • Email TemplatesTemplate builder + variables + versioning.
  • Email ValidationReal-time email verification (syntax, MX, role accounts, disposable).
  • EU RegionData stored in EU for GDPR-sensitive customers.
  • Inbound RoutingRoute incoming emails to URLs/SMTP. Attachment forwarding.
  • Mailing ListsUnlimited mailing lists with bulk subscribe/unsubscribe.
  • Open/Click TrackingHTML + text tracking with configurable tracking domain.
  • SAML SSOScale+ tier.
  • Send APIREST/SMTP send with MIME + tracking.
  • TagsTag messages to slice stats.
  • Webhook Eventsdelivered, opened, clicked, unsubscribed, complained, permanent_fail, temporary_

Developer interfaces

KindLangSmithMailgun
CLILangSmith CLI
SDKlangsmith-js, langsmith-pythonmailgun.js (Node), mailgun-php, mailgun-python, mailgun-ruby
RESTLangSmith REST APIMailgun REST API
MCPLangSmith MCP
OTHERLangSmith DashboardInbound Routing, SMTP Relay, Webhooks
Staxly is an independent catalog of developer platforms. Outbound links to LangSmith and Mailgun are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.

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