Respan AI Observability: Tracing, Evals & Pricing

Founded 2024|San Francisco, California|1-10 people|Free plan, Team subscription, Enterprise custom

What is Respan?

Respan is the AI router with built-in observability and automated evals, and its AI observability turns every LLM call, tool run, retrieval, and agent turn into a span in one nested trace, each with its own input, output, latency, and cost. Threads group multi-turn sessions, so a bad output on turn five traces back to the context set on turn two.

Evals combine an LLM judge, a deterministic code check, or a human reviewer into one evaluator, and the same evaluator runs on a test set before shipping and on live production spans after, sampled to control cost. Clicking any score lands on the trace behind it. Datasets are built straight from production logs, and experiments run a prompt or model change across a dataset with side-by-side score distributions.

Monitors watch cost, errors, latency, and tokens and alert through Slack, email, or a webhook the moment a metric breaches. Prompts are versioned and deployed without a code change, and because observability lives inside the router, every request across 1,000+ models is already traced and priced.

Key features

Core capabilities this platform advertises.

Nested traces for every LLM call, tool run, and agent turn
Threads for multi-turn sessions
Online evals on live production traffic
LLM-judge, code, and human evaluators
Datasets from production logs and experiments at scale
Monitors with Slack, email, and webhook alerts
Prompt versioning and deployment without code changes

Strengths and tradeoffs

What this tool does well, and the limitations to keep in mind.

Pros

Every score links to the trace that produced it
Evals run on live production traffic, not only on test sets
Built into the router, so there's no separate gateway to integrate
Monitors alert the moment a metric breaches
Unlimited seats on the free plan

Cons

The free plan retains data for 7 days
The free plan includes 1k scores and 2 evaluators
Ingestion throughput is metered per tier, starting at 412 logs per minute on Free

Plans & pricing

What's included in each plan, and how the tiers compare.

Free

100k logs per month
1k scores, 2 evaluators, 5 datasets, 5 prompts
7-day retention
Unlimited seats
Tracing, monitors, and alerts

Pro

$49/month

Monthly

Unlimited datasets, evaluators, and prompts
10k scores, then $1 per 1k
100k logs, then $8 per 100k
30-day retention

Enterprise

Custom

Contact sales for a quote

Custom packages and volume discounts
Custom retention
SSO and RBAC
Dedicated support
99.99% uptime SLA

View official pricing page

Common use cases

Engineering and product teams running AI agents and LLM apps in production

Debugging agent failures down to the step that broke
Catching quality regressions before users report them
Turning production failures into test datasets
Testing a prompt or model change against real cases before shipping
Attributing LLM cost to each end customer

Using Respan with Respan

Respan Observability IS the monitoring and evaluation platform. It provides real-time tracing, cost analytics, prompt management, and quality evaluation for all LLM interactions across your AI stack.

Real-time tracing of all LLM calls with detailed metrics
Automated quality evaluation of LLM outputs
Prompt versioning and A/B testing without code changes
Cost analytics across all providers from a single dashboard

Catch quality regressions before your users do

10KFree traces/mo

1,000+Models

5 minSetup

Respan traces every LLM call, tool run, and agent turn, scores output on live production traffic, and links every score to the trace behind it. Start free with 100k logs a month.

Try Respan free

Best Respan alternatives & competitors

Top companies in Observability, Prompts & Evals you can use instead of Respan.

LangSmith

Native tracing for LangChain and LangGraph