Loops vs LangSmith
Email marketing for SaaS — loops, transactional, campaigns in one
vs. LLM observability, testing & evaluation — by LangChain
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
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
Free-tier quotas head-to-head
Comparing free on Loops vs developer on LangSmith.
| Metric | Loops | LangSmith |
|---|---|---|
| No overlapping quota metrics for these tiers. | ||
Features
Loops · 12 features
- API Keys — Scoped keys for testing vs production.
- Audiences (Segments) — Filter contacts by properties + event behavior.
- Campaign Analytics — Open/click/unsubscribe rates, heatmaps, A/B significance.
- Campaigns — One-off broadcasts to audience segments. Schedule + A/B test subject.
- Contacts — Contact records with custom properties (strings, numbers, booleans, dates).
- Email Editor — Visual block-based + Markdown + HTML modes.
- Events — Send events to trigger loops/journeys or filter audiences.
- Loops (Automations) — Event-triggered automation flows with delays + conditions.
- Mailing Lists — Opt-in lists with subscribe/unsubscribe preferences per list.
- Template Library — Pre-built templates for SaaS use cases (onboarding, digest, launch).
- Transactional API — Send transactional emails (receipts, password resets) via /transactional endpoin…
- Webhooks — Subscribe to contact/event changes.
LangSmith · 14 features
- Alerts — Threshold alerts on latency, cost, eval metrics.
- Annotation Queues — Human-review workflows for trace quality rating.
- Custom Dashboards — Aggregate metrics dashboards per project/tag.
- Datasets — Collect examples → use as eval sets or training data.
- Evaluations — LLM-as-judge, embedding similarity, custom Python evaluators, offline batch eval…
- LangChain Integration — Auto-trace any LangChain/LangGraph run with env var.
- LangGraph Integration — First-class trace + eval for LangGraph agents.
- LLM Tracing — Automatic trace every LLM call + tool call + chain step.
- OpenTelemetry Export — Export traces as OTLP to Datadog/Honeycomb/etc.
- Playground — Test prompts + models inline before deploying.
- Prompt Canvas — Visual prompt editor with live test + eval.
- Prompt Hub — Public + private prompt library with versioning.
- Self-Hosted (Enterprise) — Docker + k8s deployment in your infra.
- Threads + Sessions — Group traces into conversational sessions.
Developer interfaces
| Kind | Loops | LangSmith |
|---|---|---|
| CLI | — | LangSmith CLI |
| SDK | @loops/loops, loops-py | langsmith-js, langsmith-python |
| REST | Loops REST API | LangSmith REST API |
| MCP | — | LangSmith MCP |
| OTHER | Webhooks | LangSmith 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.
Want this comparison in your AI agent's context? Install the free Staxly MCP server.