Inngest vs LangSmith
Durable functions + event-driven workflows for modern apps
vs. LLM observability, testing & evaluation — by LangChain
Pricing tiers
Inngest
Free
$0. 50K steps/mo + 1K concurrent executions. 7-day log retention. 1 environment.
Free
OSS (self-host)
Free forever. Inngest Dev Server + self-hosted Inngest runtime. Apache 2.0.
$0 base (usage-based)
Starter
$20/mo. 250K steps/mo. 5K concurrency. 14-day retention. 3 envs.
$20/mo
Pro
$75/mo. 1M steps/mo. 10K concurrency. 30-day retention. Priority support.
$75/mo
Enterprise
Custom. SSO, HIPAA, dedicated clusters, self-host with Inngest Enterprise.
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 Inngest vs developer on LangSmith.
| Metric | Inngest | LangSmith |
|---|---|---|
| No overlapping quota metrics for these tiers. | ||
Features
Inngest · 14 features
- AgentKit — Build AI agents as durable Inngest functions.
- Auto Retries — Configurable retries with exponential backoff.
- Concurrency Controls — Per-function and per-user concurrency limits.
- Cron Triggers — Scheduled functions via cron syntax.
- Debounce — Coalesce rapid-fire events into one execution.
- Dev Server — Local Inngest runtime for dev.
- Durable Steps — step.run, step.sleep, step.waitForEvent.
- Event System — Typed events with schemas.
- Fan Out / Batching — Process many events in parallel with batch control.
- Priority Lanes — Route premium customers to faster execution.
- Rate Limiting — Throttle events per key.
- Realtime — Stream function output to clients.
- Replay — Re-run past functions with new code.
- Self-Host — OSS runtime — run your own Inngest.
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 | Inngest | LangSmith |
|---|---|---|
| CLI | inngest-cli (dev server) | LangSmith CLI |
| SDK | inngestgo, inngest (Python), inngest (TS/Node) | langsmith-js, langsmith-python |
| REST | Inngest REST API | LangSmith REST API |
| MCP | Inngest MCP | LangSmith MCP |
| OTHER | Inngest Cloud Dashboard | LangSmith Dashboard |
Staxly is an independent catalog of developer platforms. Outbound links to Inngest and LangSmith are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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