Alternatives to Spool

Helicone is an AI gateway and LLM observability platform that routes, caches, and logs traffic across 100+ model providers.

LangSmith is agent and LLM observability from the LangChain team: trace, monitor, evaluate, and deploy AI agents.

Local, MIT-licensed token usage and cost tracking for AI coding agents — reads the logs your agents already write.

Arena AI ranks chat models and coding agents on live head-to-head human votes and real agent sessions.

FFMPerative Outrider turns AI research into review-ready draft pull requests matched to your codebase, then measures whether they helped.

Agent evaluation platform that simulates voice and chat agents, traces production, and scores hallucinations before your customers hit them

Synth is a research workbench and hosted compute for optimizing coding agents with reproducible, evidence-backed evals.

Open-source Python library that turns vibe checks into reproducible evaluation loops for RAG pipelines and AI agents.

Accordion is a free, MIT-licensed pi extension that shows your coding agent's entire context window as blocks you can fold, unfold, and steer.

AgentNotch streams live Claude Code and Codex token and cost telemetry into your Mac's notch

Open-source benchmark that scores AI agents on real, multi-step software-company work tasks.

AppWorld benchmarks interactive coding agents on 750 multi-app tasks across 457 APIs.

OpenJudge is an Apache 2.0 open-source AI evaluation framework shipping 50+ benchmark-validated graders for agents, LLMs, code, math, and multimodal models.

Comet's Opik brings LLM observability and evaluation that turns agent traces into code fixes

Galileo turns offline AI evals into production guardrails for agents and RAG pipelines.

Athina is a shared workspace where your team writes prompts, runs evals, annotates datasets, and traces LLM calls in production.

Conan is a native macOS HUD for Claude Code that streams every prompt, tool call, skill and token live as the session runs.

Prompt library where teams save, tag, and share ChatGPT, Claude, and Gemini prompts in one workspace.

PromptLayer is the collaboration layer for AI engineering teams — a prompt CMS, eval harness, and agent observability stack in one dashboard.

Kiln is a local-first AI workbench for building, evaluating, optimizing, and fine-tuning AI systems on your own machine.

Edgee Team token observability puts every coding agent on a budget you set, with per-repo and per-PR attribution.

OpenCode Bar tracks AI coding quota windows, spend, and burn pace from your macOS menu bar

PandaProbe is open-source agent observability that traces runs, evaluates outcomes, and turns failures into validated fixes via its Repair

CodeClash benchmarks goal-oriented software engineering by making AI models build and evolve codebases to win 15-round arena tournaments.

BALROG is an open ICLR-published benchmark that scores agentic LLM and VLM reasoning across seven procedurally generated games.

Open-source collaboration layer that turns domain expertise into AI agent test suites

Open-source LLM observability: trace agents, manage prompts, and run evals on one MIT-licensed platform.

Nebuly turns the conversations employees and customers have with your AI agents into adoption, fluency and ROI numbers for enterprise leaders.

Open-source LLM observability and agent evaluation you can trace, self-host, and eval end to end.

LangWatch is an open-source LLMOps platform for agent testing, LLM evaluation and OpenTelemetry-native LLM observability.