Humanloop has been a popular tool for product teamsand AI teams building applications with LLMs. It combined prompt management, evaluation and observability in a single platform. Following Anthropic’s acquisition of the company, Humanloop will be sunset on 8 September 2025 and all accounts and data will be deleted. Billing stopped on 30 July 2025 and the company recommends exporting data well before the shutdown. In its migration guide Humanloop suggests looking at other prompt‑management and evaluation tools such as Keywords AI, Langfuse, and Braintrust.

For teams that relied on Humanloop’s best‑in‑class tools for collaborative prompt management, version control and evaluation, moving to another platform can feel daunting. This guide compares three top alternatives - Keywords AI, Braintrust and Langfuse - and explains why Keywords AI is the natural upgrade for Humanloop users.

What made Humanloop unique?

Humanloop wasn’t just a log viewer. It provided:

• Collaborative workspace – Engineering, product and subject‑matter experts could work together to manage prompts and iterate on them
• Safe prompt iteration with version control – Users could experiment with prompts, see history of changes, evaluate performance and roll back when needed
• Unified prompt playground – A single interface allowed creation, testing and deployment of prompts across proprietary and open‑source models
• End‑to‑end prompt optimisation – Prompt data, evaluations and observability were integrated to give feedback loops for continuous improvement
• Evals‑driven and collaborative development – Humanloop emphasised evaluation‑driven iteration and cross‑functional collaboration

Those capabilities gave teams 100 % visibility into AI product performance and allowed rapid iteration.

When picking an alternative, you should look for a platform that combines observability, prompt management and evaluations, supports your workflow (UI‑first or code‑first) and is easy to migrate to.

1. Keywords AI – the all‑in‑one LLM‑Ops platform

Keywords AI was built by developers for AI product teams. It offers a unified workspace where developers and product managers can monitor and improve AI applications. Its core modules cover observability, prompt management, evaluations and a powerful AI gateway.

LLM observability

Keywords AI provides real‑time monitoring, logging and tracing of LLM requests. You can dive into individual logs to debug issues, visualise agent execution graphs and view user analytics to understand how end‑users interact with your application. Built‑in dashboards track metrics such as latency, token usage and errors.

Prompt management and version control

Humanloop users will appreciate Keywords AI’s prompt playground and prompt editor. You can test and iterate on prompts with real inputs, inspect variables and context, track usage/latency/token counts and manage versions with the ability to roll back. This mirrors the collaborative prompt versioning workflow that Humanloop pioneered, ensuring a familiar experience.

Evaluations

Keywords AI includes both online evaluations (batching multiple LLM calls) and prompt experiments to test prompts before deployment. It supports human‑ and LLM‑based scoring, allowing you to benchmark different prompts or models on custom quality metrics.

Unified AI gateway

A standout feature is Keywords AI’s AI gateway. Instead of integrating with each model separately, you send your calls to Keywords AI and it routes them to over 250 large language models. The gateway performs retries, load‑balancing, caching, prompt‑level caching and fallbacks. Benefits include:

• Calling 250+ models with the same API format
• Central management of API keys and costs
• Improved reliability through automatic retries and fallbacks

This capability is particularly helpful for teams experimenting with different providers or needing redundancy. The gateway is optional, so you can use observability and prompt‑management features without proxying requests.The gateway is optional, so you can use observability and prompt‑management features without proxying requests.

Why Keywords AI is the best choice for Humanloop users

2. Braintrust – evaluation‑first platform

Braintrust positions itself as an evals and observability platform for building reliable AI agents. It emphasises systematic evaluation of prompts and models, providing features such as:

• Evals – Braintrust allows teams to create “evals” that combine prompts, datasets and scorers. Side‑by‑side diffs show how prompt changes affect outputs. Both automated and human scoring are supported, and evals can be integrated into CI/CD pipelines
• Prompt playground and human review – A visual interface lets teams compare prompts and models, while domain experts can annotate outputs. Scorers and datasets can be chained together for sophisticated workflows
• Production monitoring – Braintrust monitors latency, cost and quality in real time and triggers alerts when quality metrics drop
• CI/CD integration and agent support – Evals can be hooked into continuous‑integration pipelines. Braintrust also offers an agent called Loop that auto‑generates prompts, datasets and scorers

Pricing and integration considerations

Braintrust offers a free tier (up to 1 million trace spans and 10 000 scores) but the Pro plan is $249 per month with additional fees for extra data. Self‑hosting and premium support require an Enterprise plan. Integration generally requires using Braintrust’s SDK or proxy; flexible observability features and cost analytics are limited. A comparison by Helicone notes that Braintrust focuses on enterprise‑grade evaluation and requires SDK‑based integration, with basic analytics and limited dashboard features.

For teams primarily interested in evaluation and already running CI/CD pipelines, Braintrust can be a strong fit. However, product teams seeking comprehensive observability and cost tracking may find it lacking.

3. Langfuse – observability‑first platform

Langfuse is an open‑source platform for LLM tracing, prompt management and evaluation. The company recently open‑sourced all previously commercial features (LLM‑as‑a‑Judge, annotation queues, prompt experiments and the playground) under an MIT licence. Key attributes include:

• Open source and self‑hostable – Langfuse’s core tracing is MIT‑licensed and designed to be freely available. You can self‑host the entire platform or use Langfuse Cloud
• Developer‑first – Langfuse explicitly targets developers and provides an API‑first platform. It supports OpenTelemetry and integrates with major LLM frameworks (LangChain, LlamaIndex, Vercel AI SDK, etc.)
• Detailed tracing for complex workflows – Langfuse captures hierarchical traces of LLM calls, enabling debugging of complex, nested workflows
• Prompt management and versioning – The prompt‑management module includes version control, composability and A/B testing; prompts can be cached for low latency
• Evaluation methods – Langfuse supports LLM‑as‑a‑judge evaluations, manual annotations and custom scoring. Its open‑source nature means new evaluation methods can be added by the community.

Who Langfuse is best for

Langfuse is ideal if you prefer open source with simple self‑hosting, need detailed tracing for complex workflows and are comfortable with an SDK‑based approach. Because it is built for developers, the interface is code‑heavy; non‑technical product managers may find it less intuitive. It does not include built‑in cost tracking or caching by default, so additional tooling may be needed for full operational analytics.

Comparison summary

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| Platform        | Strengths                                                                                                                                                                                                                                                               | Integration & pricing                                                                                                                                | Best for                                                                                                                                                                                                      |

| --------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Keywords AI | Complete observability (real‑time monitoring, logging, agent tracing and user analytics); collaborative prompt playground and editor with version control; online and human/LLM evaluations; AI gateway to call 250+ models with one API and automatic retries/caching. | OpenAI‑compatible API; optional proxy/gateway; integrates with common frameworks; pricing tailored to startups (free tier plus scalable paid plans). | Teams that need an all‑in‑one replacement for Humanloop with seamless migration and a polished UI/UX. | | Braintrust | Strong evaluation framework with automated and human scoring; visual prompt playground and side‑by‑side comparisons; CI/CD integration and production monitoring. | Requires SDK or proxy integration; pricing starts at $249/month for Pro plan; limited analytics and dashboards. | Enterprises and engineering teams whose primary need is systematic evals and who are willing to pay for enterprise‑grade features. | | Langfuse | Open source and self‑hostable; developer‑first with API‑first design; detailed LLM tracing for complex workflows; versioned prompt management and A/B testing; multiple evaluation methods. | SDK‑based integration; community‑driven support; no built‑in cost tracking or caching; self‑hosting may require DevOps effort. | Engineering teams who need fine‑grained tracing and value open source; comfortable with code‑heavy workflows and willing to build additional analytics. Teams that need an all‑in‑one replacement for Humanloop with seamless migration and a polished UI/UX. |

Final thoughts

Humanloop’s shutdown on 8 September 2025 leaves many teams searching for a new home for their prompts, evaluations and observability workflows. While platforms like Braintrust and Langfuse offer strong evaluation or open‑source tracing capabilities, Keywords AI is the only alternative that combines observability, prompt management, evaluations and an optional AI gateway in a single, developer‑ and product‑friendly package. Its familiar feature set, easy integration and comprehensive support make it the natural upgrade for Humanloop users. Export your Humanloop data well before the September deadline. Experiment with the alternatives, and give Keywords AI a try to keep your LLM applications reliable, observable and easy to iterate on.