Decision comparison
Neptune.ai vs Weights & Biases
Neptune.ai is no longer an option: it shut down its hosted service permanently on March 5, 2026, after its acquisition by OpenAI, and deleted all external user data, so there is nothing left to export or migrate. The Neptune.ai descriptions on this page are historical context, not current features. Of the two tools compared here, only Weights & Biases can be chosen today. Choose it for teams that need a publicly priced entry point, rich reproducibility metadata, collaboration controls, registry/lineage capabilities, and explicitly described local or enterprise deployment options.
Neptune.ai is no longer available as an active product
Neptune.ai shut down its hosted service permanently on March 5, 2026 following its acquisition by OpenAI, and all external user data was deleted. There is nothing left to export or migrate. Treat this page as historical context rather than a current buying page.
Active alternatives to evaluate
Direct comparison. These are reviewed substitutes bought for the same job, so the differences below are the ones that decide between them.
All 2 are experiment tracking.
Quick Comparison
| Decision factor | Neptune.ai | Weights & Biases |
|---|---|---|
| Best For | Nothing today: Neptune.ai shut down its hosted service permanently on March 5, 2026, after its acquisition by OpenAI, and deleted all external user data. It was built for frontier and foundation-model research that needed months-long training monitoring, branch-aware experiment tracking and fast comparison across thousands of metrics. | ML teams needing collaborative debugging, reproducibility, experiment tracking, asset lineage, and model management from experimentation through production. |
| Architecture | Historically a hosted experiment tracker: a Python client library logged model-training metadata to Neptune's service. Its documentation described a hosted product, not a self-hosted deployment, and that hosted service no longer runs. | AI developer platform with experiment tracking and registry/lineage; Personal supports running a W&B server locally using Docker and Python. |
| Pricing Model | No longer sold. The hosted service shut down on March 5, 2026, so there is no plan to buy, no quote to request and no free tier. Before the shutdown it was sold as an Enterprise product without published dollar rates; none of those terms apply today. | Weights & Biases is now part of CoreWeave Forge, whose pricing page lists the plans. Free: $0 per month, up to 5 model seats, 5 GB of storage and 1 GB of Weave data ingestion a month. Pro: starts at $60 per month, billed monthly, for early-stage teams with fewer than 50 employees; up to 10 model seats, 100 GB of storage and 1.5 GB of Weave data ingestion a month; additional storage $0.03 per GB and additional Weave data ingestion $0.10 per MB. Enterprise: custom plans with customizable seats, storage and ingestion; additional Weave data ingestion $0.20 per MB. Academic: free, with unlimited projects and teams and 200 GB of cloud storage. Verified 2026-10-09 against https://coreweave.com/forge-pricing. |
| Ease of Use | Historical only: it was built around monitoring and visualizing how training evolved, with filtering and search across large experiment datasets and comparison across many metrics. None of it can be used today. | Account-based onboarding supports tracking pipeline components, debugging and comparing runs, plus team collaboration and reproducibility workflows. |
| Scalability | Historical only: it was designed to retain massive training data, filter it rapidly and compare thousands of metrics during long-running, multi-step, branched training. The data it held for external users was deleted at the shutdown. | Enterprise offers single-tenant regional deployment, private connectivity, customer-managed encryption keys, SSO, and a HIPAA-compliant option. |
| Community/Support | No vendor support since the March 5, 2026 shutdown. Its Python client repository has 16 stars and a latest release of 0.30.0, and it remains only as a record of a service that no longer runs. | MIT-licensed Python repository with 11,246 stars; Pro includes priority email and chat support, while Enterprise adds deployment options. |
Neptune.ai
- Best For:
- Nothing today: Neptune.ai shut down its hosted service permanently on March 5, 2026, after its acquisition by OpenAI, and deleted all external user data. It was built for frontier and foundation-model research that needed months-long training monitoring, branch-aware experiment tracking and fast comparison across thousands of metrics.
- Architecture:
- Historically a hosted experiment tracker: a Python client library logged model-training metadata to Neptune's service. Its documentation described a hosted product, not a self-hosted deployment, and that hosted service no longer runs.
- Pricing Model:
- No longer sold. The hosted service shut down on March 5, 2026, so there is no plan to buy, no quote to request and no free tier. Before the shutdown it was sold as an Enterprise product without published dollar rates; none of those terms apply today.
- Ease of Use:
- Historical only: it was built around monitoring and visualizing how training evolved, with filtering and search across large experiment datasets and comparison across many metrics. None of it can be used today.
- Scalability:
- Historical only: it was designed to retain massive training data, filter it rapidly and compare thousands of metrics during long-running, multi-step, branched training. The data it held for external users was deleted at the shutdown.
- Community/Support:
- No vendor support since the March 5, 2026 shutdown. Its Python client repository has 16 stars and a latest release of 0.30.0, and it remains only as a record of a service that no longer runs.
Weights & Biases
- Best For:
- ML teams needing collaborative debugging, reproducibility, experiment tracking, asset lineage, and model management from experimentation through production.
- Architecture:
- AI developer platform with experiment tracking and registry/lineage; Personal supports running a W&B server locally using Docker and Python.
- Pricing Model:
- Weights & Biases is now part of CoreWeave Forge, whose pricing page lists the plans. Free: $0 per month, up to 5 model seats, 5 GB of storage and 1 GB of Weave data ingestion a month. Pro: starts at $60 per month, billed monthly, for early-stage teams with fewer than 50 employees; up to 10 model seats, 100 GB of storage and 1.5 GB of Weave data ingestion a month; additional storage $0.03 per GB and additional Weave data ingestion $0.10 per MB. Enterprise: custom plans with customizable seats, storage and ingestion; additional Weave data ingestion $0.20 per MB. Academic: free, with unlimited projects and teams and 200 GB of cloud storage. Verified 2026-10-09 against https://coreweave.com/forge-pricing.
- Ease of Use:
- Account-based onboarding supports tracking pipeline components, debugging and comparing runs, plus team collaboration and reproducibility workflows.
- Scalability:
- Enterprise offers single-tenant regional deployment, private connectivity, customer-managed encryption keys, SSO, and a HIPAA-compliant option.
- Community/Support:
- MIT-licensed Python repository with 11,246 stars; Pro includes priority email and chat support, while Enterprise adds deployment options.
Public signals
Verified factual signals only. Bars appear only for like-for-like metrics with five weekly assessments for every tool; missing evidence stays explicit. These signals do not establish enterprise adoption, product quality, or total cost.
| Metric | Neptune.ai | Weights & Biases |
|---|---|---|
| GitHub commits, 90d(Developer adoption) | 0 | Not available |
| GitHub stars(Developer adoption) | 16 | Not available |
| Search interest(Market interest) | 0 | 0 |
| Product Hunt comments(Community interest) | 0 | 8 |
| Product Hunt rating(Community interest) | Unavailable | 5.0/5 |
| Product Hunt reviews(Community interest) | 0 | 3 |
| Product Hunt votes(Community interest) | 6 | 110 |
| PyPI weekly downloads(Developer adoption) | 22.5k | Not available |
| Stack Overflow questions(Community interest) | 20 | 139 |
| Docker Hub pulls(Product adoption) | Not available | 4.1M |
| GitHub commits, 90d(Product adoption) | Not available | 514 |
| GitHub stars(Product adoption) | Not available | 11,000+ |
| Hacker News mentions, 90d(Community interest) | Not available | 0 |
| Hugging Face downloads(Product adoption) | Not available | 3.3k |
| Hugging Face likes(Product adoption) | Not available | 33 |
| npm weekly downloads(Developer adoption) | Not available | 3.8k |
| PyPI weekly downloads(Product adoption) | Not available | 4.6M |
As of November 9, 2026 — updated weekly.
Health & risk evidence
Observed public-source checks for mapped package versions and repositories.
Neptune.ai
November 9, 2026Package vulnerabilities
PyPI · neptune@1.14.0.post2
0 vulnerabilities
across 1 package
Repository security score
Not available
Weights & Biases
November 9, 2026Package vulnerabilities
npm · @wandb/sdk@0.5.1 · PyPI · wandb@0.31.0
0 vulnerabilities
across 2 packages
Repository security score
Not available
Interface Preview
Neptune.ai
Weights & Biases
Feature Comparison
| Feature | Neptune.ai | Weights & Biases |
|---|---|---|
| Experiment tracking depth | ||
| Training-run tracking | Tracked foundation-model training across multiple steps and branches until the March 5, 2026 shutdown | Tracks AI model experiments with reproducibility metadata |
| Metric analysis | Visualized and compared thousands of metrics in seconds | Debugs and compares model runs and pipeline pieces |
| Long-running research | Monitored months-long model training as it evolved | Manages models from experimentation through production |
| Metadata and reproducibility | ||
| Captured model context | Logged model-training metadata through its Python client library | Captures architecture, hyperparameters, Git commits, model weights, and GPU usage |
| Data and prediction context | Documentation emphasized training metadata and metric histories | Tracks datasets and predictions alongside model experiments |
| Lineage management | Not described in its documentation | Provides AI assets registry and lineage tracking on Free |
| Exploration workflow | ||
| Search large experiment data | Filtered and searched massive amounts of tracked data quickly | Documentation describes run comparison and debugging workflows |
| Branch-aware analysis | Tracked training workflows with multiple steps and branches | Not available in the public documentation |
| Training behavior visibility | Helped researchers understand complex model behavior in real time | Visualizes all pieces of the machine-learning pipeline |
| Collaboration and access | ||
| Team collaboration | Documentation focused on researcher experiment-tracking workflows | Supports teammate collaboration on experiments and models |
| Access controls | Not described in its documentation | Pro includes team-based access controls and service accounts |
| Enterprise identity and security | Sold as Enterprise before the shutdown; security capabilities were not specified | Enterprise includes SSO, private connectivity, and customer-managed encryption keys |
| Deployment and commercial access | ||
| Entry-level access | None: the service shut down on March 5, 2026, and is no longer sold | Free includes evaluations, tracing, scorers, tracking, and lineage |
| Local deployment | Not described in its documentation; the hosted service no longer runs | Personal permits local W&B server with Docker and Python |
| Enterprise deployment | Not available: the hosted service shut down and all external user data was deleted | Enterprise offers single-tenant deployment with regional choice |
Experiment tracking depth
Training-run tracking
Metric analysis
Long-running research
Metadata and reproducibility
Captured model context
Data and prediction context
Lineage management
Exploration workflow
Search large experiment data
Branch-aware analysis
Training behavior visibility
Collaboration and access
Team collaboration
Access controls
Enterprise identity and security
Deployment and commercial access
Entry-level access
Local deployment
Enterprise deployment
Which to choose
Neptune.ai is no longer an option: it shut down its hosted service permanently on March 5, 2026, after its acquisition by OpenAI, and deleted all external user data, so there is nothing left to export or migrate. The Neptune.ai descriptions on this page are historical context, not current features. Of the two tools compared here, only Weights & Biases can be chosen today. Choose it for teams that need a publicly priced entry point, rich reproducibility metadata, collaboration controls, registry/lineage capabilities, and explicitly described local or enterprise deployment options.
Best-fit scenarios
Neptune.ai (no longer available):
Neptune.ai cannot be chosen today: it shut down its hosted service permanently on March 5, 2026, after its acquisition by OpenAI, and deleted all external user data, so there is no account to open, no plan to buy and no history to recover. It was built for foundation-model research: observing months-long, branched training, searching very large experiment histories and comparing thousands of metrics. Of the tools on this page, Weights & Biases now covers that need. It tracks model experiments with architecture, hyperparameters, Git commits, model weights, GPU usage, datasets and predictions, lets teams debug and compare runs, and includes asset registry and lineage on its Free tier. One gap: W&B's documentation does not describe the branch-aware analysis Neptune.ai was built around, so test your branched training workflows on W&B before you commit to it. Teams that want open-source software can also evaluate MLflow for ML lifecycle management.
Choose Weights & Biases if:
Choose Weights & Biases when a small or growing ML team needs Free or $60/mo Pro access, collaborative debugging, detailed run metadata, asset lineage, or enterprise security controls.
These scenarios reflect the available product evidence. Your requirements, existing stack, and team expertise should guide the final decision.
Frequently Asked Questions
What is the main difference between Neptune.ai and Weights & Biases?
Today the main difference is that only Weights & Biases is available. Neptune.ai shut down its hosted service permanently on March 5, 2026, after its acquisition by OpenAI, and deleted all external user data. Before that, Neptune.ai was an experiment tracker for foundation-model training, with particular emphasis on months-long runs, multiple steps and branches, fast searching through massive data, and comparison of thousands of metrics. Weights & Biases is described more broadly as an AI developer platform: it captures architecture, hyperparameters, Git commits, model weights, GPU usage, datasets, and predictions; it also emphasizes collaboration, asset registry and lineage, and managing models from experimentation to production.
Which is better for small teams?
Weights & Biases, because Neptune.ai is no longer available to any team: it shut down its hosted service on March 5, 2026. W&B's Free tier includes AI application evaluations, tracing, scorers, model experiment tracking, and asset registry and lineage tracking. Its Pro plan is $60/mo and includes unlimited teams for collaboration, team-based access controls, service accounts, and priority email and chat support.
Can I migrate from Neptune.ai to Weights & Biases?
No. Neptune.ai deleted all external user data when it shut down its hosted service on March 5, 2026, after its acquisition by OpenAI. There are no runs, metric histories, parameters or artifacts left to export or move. Former Neptune.ai users who still need experiment tracking start a new history: Weights & Biases records architecture, hyperparameters, Git commits, model weights, GPU usage, datasets and predictions from the first run you log to it.
What are the pricing differences?
Neptune.ai has no price today. It is no longer sold, because its hosted service shut down permanently on March 5, 2026, after its acquisition by OpenAI; the Enterprise terms it was sold under before the shutdown no longer apply. Weights & Biases publishes several concrete options: Free includes evaluations, tracing, scorers, experiment tracking, and registry/lineage; Pro is $60/mo with collaboration and support features; Enterprise is contact sales with single-tenant, security, connectivity, and regional deployment options. Personal is $0/mo for one user and personal projects only; corporate use is prohibited.
What happened to Neptune.ai and its data?
Neptune.ai shut down its hosted service permanently on March 5, 2026, after its acquisition by OpenAI, and deleted all external user data. Nothing is left to export, restore or migrate, the product is no longer sold and it has no support. The Neptune.ai descriptions on this page are kept as historical context for readers who used it, or who want to compare its former approach with Weights & Biases before they choose an experiment tracker.