Staxly

Loops vs LangSmith

Email marketing for SaaS — loops, transactional, campaigns in one
vs. LLM observability, testing & evaluation — by LangChain

Loops websiteLangSmith website

Pricing tiers

Loops

Free
1,000 subscribed contacts. 4,000 sends/month. All features. Loops footer on emails.
Free
Paid — 1.5k
1,500 contacts. Unlimited sends. No footer.
$15/mo
Paid — 5k
5,000 contacts. Unlimited sends.
$49/mo
Paid — 10k
10,000 contacts.
$99/mo
Paid — 25k
25,000 contacts.
$199/mo
Paid — 50k
50,000 contacts.
$349/mo
Custom
>100k contacts — contact sales.
Custom
Loops website

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

Free-tier quotas head-to-head

Comparing free on Loops vs developer on LangSmith.

MetricLoopsLangSmith
No overlapping quota metrics for these tiers.

Features

Loops · 12 features

  • API KeysScoped keys for testing vs production.
  • Audiences (Segments)Filter contacts by properties + event behavior.
  • Campaign AnalyticsOpen/click/unsubscribe rates, heatmaps, A/B significance.
  • CampaignsOne-off broadcasts to audience segments. Schedule + A/B test subject.
  • ContactsContact records with custom properties (strings, numbers, booleans, dates).
  • Email EditorVisual block-based + Markdown + HTML modes.
  • EventsSend events to trigger loops/journeys or filter audiences.
  • Loops (Automations)Event-triggered automation flows with delays + conditions.
  • Mailing ListsOpt-in lists with subscribe/unsubscribe preferences per list.
  • Template LibraryPre-built templates for SaaS use cases (onboarding, digest, launch).
  • Transactional APISend transactional emails (receipts, password resets) via /transactional endpoin
  • WebhooksSubscribe to contact/event changes.

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.

Developer interfaces

KindLoopsLangSmith
CLILangSmith CLI
SDK@loops/loops, loops-pylangsmith-js, langsmith-python
RESTLoops REST APILangSmith REST API
MCPLangSmith MCP
OTHERWebhooksLangSmith Dashboard
Staxly is an independent catalog of developer platforms. Some links to Loops and LangSmith may be affiliate links — Staxly may earn a commission if you sign up through them, at no extra cost to you. Pricing is verified against vendor pages at publication time — reconfirm before buying.

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