The AI router with built-in
observability & automated evals
Route every model through one API, then trace, monitor, and red-team every agent run.
Latest models with the best deals
All models001Gateway
Reach every model, and stay up.
Point the SDK you already use at one endpoint to reach 1,000+ models, with automatic fallbacks, response caching, and spend limits built in.
One API for every model
Send every request to one endpoint, reach 1,000+ models across every major provider, and switch between them by changing a single word.
One model fails, the next takes over
List the models to fall back to, and Respan moves to the next the moment one errors or rate-limits, so an outage never takes you down.
Repeat requests served from cache
Cache a request and its response, then serve the same call again instantly, cutting the cost and latency of every repeat to nothing.
Budgets and limits at every scope
Set budgets and rate limits per key, per customer, or org-wide, get warned as you near them, and block requests before spend runs away.
002Evals
Ship the version that scores best.
Score every output against the bar you set, so you know it holds up on a test set and in production, instead of just hoping it does.
Every way to grade an output, in one evaluator
An LLM judge, a deterministic code check, or a human reviewer, composed into one evaluator that turns any output into a single score.
Production traffic
Sampling 2% of 12,480 requests
Test cases sampled straight from production
Pull real requests from your logs by filter and sampling rate, or upload a CSV, so every case is one your users actually sent.
See which version scores better, before you ship
Run a model or prompt against the dataset, then compare their score distributions side by side, so you ship the change that measurably wins.
Faithfulness
Scoring 5% of production spans
The same evaluator, now scoring live traffic
Deploy an evaluator on production spans, filtered by status, customer, or thread and sampled to control cost, so regressions surface in real time.
003Monitoring
Know the moment things change.
Track requests, errors, cost, latency, and tokens on one dashboard, and get alerted the moment any of them crosses a threshold you set.
An alert the instant a metric crosses its limit
Watch cost, errors, latency, or tokens over any window, and the alert reaches Slack, email, or a webhook the moment it breaches.
Every metric on one dashboard
Requests, errors, cost, latency, and tokens across all your traffic, sliced by model, key, or user, so a spike is easy to spot.
004Tracing
See exactly what your agents did.
Every LLM call, tool run, retrieval, and agent turn becomes a span in one trace, with its input, output, latency, and cost captured.
Every step of a request, in one trace
LLM calls, tool runs, retrievals, and agent turns each become a span in one trace, showing exactly where a run's time and cost go.
{
"model": "claude-opus-4-8",
"temperature": 0.2,
"max_tokens": 1024,
"messages": [
{ "role": "system", "content": "You are a support agent. Answer only from the retrieved context." },
{ "role": "user", "content": "Why was I charged twice this month?" },
{ "role": "assistant", "content": "Let me check your recent invoices and payment retries." }
]
}Any span, down to the last field
Model, latency, cost, tokens, and the exact input and output sit on every span, showing precisely what each step ran and returned.
The AI observability platform behind 80 trillion+ tokens.
Loved by world-class founders, engineers, and product teams.
“Imagine jumping to a log immediately after every LLM call. This is the dream for debugging.”
Daniel Wolf
Product Lead, AlphaSense
“We scaled from 5M to 500M+ monthly API calls quickly. Respan gave us the debugging layer to resolve production issues 10x faster.”
Read how Retell builds next-gen voice agents that scale->Zexia Zhang
CTO, Retell AI
“Respan legit has some of the best UX/DX I’ve ever seen in my life. I truly don’t think I’ve ever integrated a product that was as easy.”
Rahul Behal
Co-founder, Gumloop
“This one felt pretty nice.”
Fabian Hedin
CTO, Lovable
“Such a no brainer choice over LangSmith or anything else and super easy to set up.”
Andy Wang
CEO, Finta
“Respan has been key in helping us scale to trillions of tokens reliably with real-time observability.”
Read how Mem0 builds reliable self-improving AI memory layer->Deshraj Yadav
CTO, Mem0
“Great product - really love the metrics dashboard.”
Esha Dinne
CTO, Giga
Certified where it counts.
Built to meet the security and privacy standards that enterprise and healthcare teams require.
ISO 27001
The internationally recognized standard for information security management.
SOC 2
Secure, compliant management of your data across all of our systems.
GDPR
Operated under GDPR, the world's strictest standard for data privacy.
HIPAA
HIPAA compliant, with a BAA available for healthcare teams.
Works with your entire stack
Use Respan with your favorite frameworks and tools.
