Respan Review 2026: LLM Gateway, Observability, Evals, and Pricing

Respan is a credible shortlist choice for teams that want one control plane for model routing, agent traces, prompt releases, evaluation, spend, and operational alerts. The generous free allowance makes a realistic pilot possible. Its biggest architectural tradeoff is concentration: routing and logging every model call through one vendor improves visibility but also creates a sensitive data path and a potential dependency that must be tested under failure.

• Teams operating multiple model providers
• Developers debugging production AI agents
• Organizations unifying gateway, prompts, evals, and spend

• Workloads that cannot send traces through a third party
• Teams needing an evaluator to act as ground truth
• Simple low-volume prototypes with no operations burden

Current first-party material covers a unified gateway for hundreds of models, provider fallback, retries, load balancing, caching, key storage, budgets, rate limits, OpenTelemetry-compatible tracing, multimodal logs, prompt versioning, datasets, deterministic and LLM-judge evaluators, human review, production sampling, custom dashboards, and alerts through Slack, email, or webhooks. The former Keywords AI URLs now redirect to the Respan brand, while the legal entity remains Keywords AI, Inc.

Prompts, outputs, tool arguments, retrieved content, and user identifiers may enter traces unless teams omit or mask them. Automated evaluators are not ground truth and require calibration against expert labels. Gateway outages, routing changes, cache semantics, provider-specific features, and retry behavior can alter quality or duplicate consequential actions. The $199 Team figure is annualized, and downstream model inference remains an additional cost.

Respan lists a $0 Free plan with 100,000 logs, 1,000 scores, five datasets, two evaluators, five prompts, seven-day retention, and one workspace. Team is $199 per month when billed annually and adds unlimited datasets, evaluators, and prompts, 30-day retention, five members, and private Slack support. Extra usage is listed at $8 per 100,000 logs and $1 per 1,000 scores; additional Team seats are $15 per member. Enterprise and model-provider charges are separate or custom. Reviewed September 9, 2026.

Mirror five percent of sanitized production traffic for two weeks, then route a reversible workload through Respan with direct-provider bypass available. Compare trace completeness, evaluator agreement with 300 expert labels, fallback correctness, cache safety, p50 and p95 latency, gateway and provider errors, cost attribution, PII masking, export quality, and recovery during an injected outage. Calculate platform cost per investigated failure and per accepted output.

Respan earns a pilot for teams whose model traffic, evaluations, and prompts have outgrown separate dashboards and scripts. Use the free tier to prove trace quality and incident-time savings, keep a tested provider bypass, exclude sensitive fields by default, and grant production evaluators authority only after measuring false positives and false negatives.

This is a research-based product assessment, not a claim of hands-on long-term testing. Product, pricing, privacy, security, ownership, and usage claims were checked against the first-party sources below on September 9, 2026. Verify current terms and run the proposed test with approved data before adoption.