Software Alternatives & Startups

Spanlens VS LightEval

Compare Spanlens VS LightEval and see what are their differences

Spanlens

Open source LLM observability and monitoring for OpenAI, Anthropic, and Gemini. Request logging, cost tracking, agent tracing. Self-hostable, MIT licensed.

Rating
0 reviews
Pricing
Open source Freemium $29 / Monthly (Pro)
LightEval

Lighteval is your all-in-one toolkit for evaluating LLMs across multiple backends - huggingface/lighteval

No screenshot yet
Rating
0 reviews

Which is more popular?

AI popularity
55% vs 45%
alternatives listed
20 vs 8

Base details

Website, pricing, platforms and company facts side by side.

Spanlens
LightEval
Website spanlens.io github.com
Pricing
Open source Freemium $29 / Monthly (Pro) Official pricing
—
Company 2026 —
Listed in

About Spanlens and LightEval

In their own words, as submitted to SaaSHub.

Spanlens
LightEval

Spanlens is an open source observability tool for LLM apps. You point your OpenAI, Anthropic, or Gemini client at the Spanlens proxy by changing the baseURL, and it records every request with the full body, token counts, cost, and latency. The dashboard shows per-model costs, latency percentiles,...

Read more about Spanlens

No description of LightEval yet.

Features and specs

What each product offers, as listed by its team.

Spanlens 5 features
LightEval 5 features
  • Real-time translation
    Spanlens offers real-time translation capabilities, allowing users to quickly convert speech or text between Spanish and other languages, which is useful for immediate communication needs.
  • Language learning support
    The platform appears designed to assist users in learning Spanish, providing tools that combine translation with educational features to help build vocabulary and comprehension.
  • Accessibility
    As a web-based tool, Spanlens is accessible from any device with an internet connection, eliminating the need for software installation and making it convenient for on-the-go use.
  • User-friendly interface
    The platform is designed with simplicity in mind, making it easy for users of varying technical skill levels to navigate and utilize its translation and learning features.
  • Focused niche
    By specializing in Spanish language tools, Spanlens can potentially offer more refined and accurate features compared to general-purpose translation apps that cover many languages.
  • Multiple backend support
    LightEval can run evaluations across several backends, including Hugging Face Transformers, accelerate, vLLM, Nanotron, and inference endpoints or APIs. This lets users evaluate models on local hardware or on hosted services without rewriting their evaluation setup.
  • Large built-in task library
    It ships with a broad catalog of benchmarks, including many from the Open LLM Leaderboard and the wider academic evaluation ecosystem (MMLU, ARC, HellaSwag, GSM8K, and others). This reduces the work needed to start benchmarking a model.
  • Detailed per-sample results
    Unlike many evaluation tools that only report aggregate scores, LightEval can save sample-by-sample outputs and details. This makes it easier to inspect failures, debug prompts, and compare models in depth.
  • Customizable tasks and metrics
    Users can define their own tasks, prompt formats, and metrics, and can add custom evaluation logic. This flexibility is useful for domain-specific evaluation and research experiments.
  • Hugging Face ecosystem integration
    It integrates well with the Hugging Face Hub, datasets, and related tooling, and results can be pushed to the Hub or tracked with tools like Weights & Biases. It is also actively developed and open source, which suits teams already on Hugging Face.

Possible disadvantages

  • Smaller community than alternatives
    Compared with EleutherAI's lm-evaluation-harness, LightEval has a smaller user base and fewer community-contributed tasks and examples. Finding answers to edge-case problems can be harder.
  • Rapidly evolving API
    The project has changed quickly, with shifts in CLI usage, task specification formats, and configuration. Older tutorials or scripts may break between versions, and users may need to keep up with migrations.
  • Steeper setup for custom tasks
    Writing custom tasks and metrics often requires understanding its internal abstractions, such as prompt functions, task configs, and metric definitions. This can be a learning curve for newcomers.
  • Documentation gaps
    Although documentation has improved, some advanced features, backend-specific options, and troubleshooting scenarios are less thoroughly covered. Users may need to read source code to understand certain behaviors.
  • Reproducibility differences across tools
    Scores may differ from those produced by other harnesses because of differences in prompt formatting, few-shot sampling, and normalization. This can make it hard to compare results against published numbers without careful configuration.

Analysis

An editorial look at what each product does well and who it suits.

Spanlens
LightEval

Overall verdict

  • I don't have verified, reliable information about Spanlens (spanlens.io) to make a confident assessment of its quality, legitimacy, or performance. Before using or purchasing from this service, I'd recommend conducting independent research.

Why this product is good

  • No verified data available on this specific product/service to confirm its features or quality
  • Unable to confirm the legitimacy, reputation, or track record of this website
  • Cannot verify user reviews, ratings, or customer satisfaction levels
  • No information on pricing, terms of service, or company background to evaluate

Recommended for

  • Research this independently before making any decisions
  • Check for reviews on trusted third-party platforms (Trustpilot, Reddit, BBB)
  • Verify company registration, contact information, and business legitimacy
  • Look for user testimonials or case studies from verified customers
  • Consider reaching out to the company directly with questions before committing

No analysis of LightEval yet.

Category popularity

How often each product is chosen within a category, 0–100% relative to the other.

Score bands 0–20 21–40 41–50 51–60 61–100
Spanlens
LightEval
55% 55%
AI
45% 45%
31% 31%
69% 69%
100% 100%
0% 0%
100% 100%
0% 0%

Questions & Answers

As answered by people managing Spanlens and LightEval.

What's the story behind your product?

Spanlens's answer

I was building LLM apps on the side and kept pasting token counts into a spreadsheet to figure out what each feature cost me. The tools I tried were either acquired mid-migration, closed source, or heavier to self-host than the app I was trying to monitor. So in April 2026 I started building the tool I actually wanted: change one line, see every request. It launched in June 2026, and the whole codebase went up on GitHub under MIT from day one.

What makes your product unique?

Spanlens's answer

The entire product is MIT licensed, including the dashboard, evals, and prompt A/B testing. There is no separate enterprise edition. Everything ships in one repo you can run with a single Docker Compose file. Integration is one line: you change the baseURL on your OpenAI, Anthropic, or Gemini client, and every call gets logged with its full body, token counts, cost, and latency. A few things that are usually paid add-ons come built in, like agent traces with a critical path view, A/B tests that use Welch's t-test to tell you whether a difference is real, and a recommender that flags cheaper models based on the traffic you actually send.

Why should a person choose your product over its competitors?

Spanlens's answer

Mostly because of where the market went. Helicone was acquired, LangSmith is closed source, and self-hosting Langfuse takes real setup work. Spanlens fills the gap those tools left: setup in about five minutes, one Docker Compose file if you want the data on your own servers, and no feature gating between free and paid tiers. To be fair, if you need SOC 2 reports and enterprise support today, the bigger platforms are ahead. If you want request logs, costs, and traces without adopting a heavy platform, that is what Spanlens was built for.

How would you describe the primary audience of your product?

Spanlens's answer

Developers who ship LLM features in production apps. The typical user is a solo developer or a small team that added OpenAI or Anthropic calls to their product and now has no clear picture of what those calls cost or why some are slow. Agent builders are the second group, since multi-step workflows are hard to debug without traces. It is a developer tool through and through: if you don't touch code, you won't get much out of it.

Who are some of the biggest customers of your product?

Spanlens's answer

We don't publish customer names yet. Spanlens launched in June 2026, and most users so far are indie developers and small AI teams.

Which are the primary technologies used for building your product?

Spanlens's answer

TypeScript across the stack. The dashboard is Next.js, the API and proxy run on Hono, and data is split between Supabase Postgres for accounts and relational data and ClickHouse for request logs, which grow fast. The repo is a pnpm monorepo that also holds the JavaScript and Python SDKs, a CLI, and an MCP server. Self-hosting runs on Docker Compose, and OpenTelemetry traces can be ingested over OTLP.

User comments

Share your experience with using Spanlens and LightEval. For example, how are they different and which one is better?

Log in or Post with

Alternatives to Spanlens and LightEval

When comparing Spanlens and LightEval, you can also consider the following products.