neptune.ai
Neptune.ai built a hosted SaaS platform for AI experiment tracking and model training observability, serving ML researchers and AI labs. Acquired by OpenAI in December 2025 for under $400 million, with its external platform winding down by March 2026.
- Company typePrivate
- Founded2018
- HeadquartersPalo Alto, United States
- Headcount51–100
- GTM typeB2B
- OfferingSoftware
What neptune.ai does
Neptune.ai was a Polish-founded software company specializing in experiment tracking and model training observability for machine learning teams. Spun out of Deepsense in 2018 and headquartered in Warsaw, the company built a hosted SaaS platform paired with a Python client library (neptune-client) that enabled AI researchers and ML engineers to log, monitor, and compare thousands of training runs in real time, analyze metrics across model layers, and surface anomalies during training. Its tooling integrated with the dominant ML frameworks (TensorFlow, PyTorch, Scikit-learn) and was used by AI labs including HeyGen, poolside, and InstaDeep, as well as OpenAI's own frontier training operations for over a year prior to acquisition.
The platform monetized via a freemium self-serve SaaS model supplemented by custom enterprise plans, distributed through content marketing, developer relations, and direct online sign-up (a product-led growth motion). The company raised approximately $18 million in venture funding across rounds in 2018, 2020, and 2022 from investors including TDJ Pitango Ventures, Almaz Capital, b2venture, and Rheingau Founders, scaling to over 50 employees.
On December 3, 2025, OpenAI entered a definitive agreement to acquire Neptune.ai in an all-stock transaction reported at just under $400 million, with the stated goal of integrating the company's experiment-tracking and training-monitoring tools into OpenAI's internal training stack. Following the acquisition, Neptune's external hosted platform was scheduled to wind down by March 5, 2026, requiring external customers to migrate, while the technology and team continue operationally inside OpenAI.
neptune.ai firmographics
Firmographics- Name
- neptune.ai
- Legal name
- Neptune.ai
- Website
- https://neptune.ai
- Company type
- Private
- Founded year
- 2018
- Operating status
- Acquired
- Headcount range
- 51–100 employees
- Short description
- Neptune.ai built a hosted SaaS platform for AI experiment tracking and model training observability, serving ML researchers and AI labs. Acquired by OpenAI in December 2025 for under $400 million, with its external platform winding down by March 2026.
- Ownership category
- akta.pro rank
neptune.ai industry classification
Industry- Product category
- MLOps and AI Training Observability Software
- NAICS
- Computer Systems Design and Related Services (54151)
- SIC
- Services-Prepackaged Software (7372)
- akta.pro primary industry
- AI Observability, Monitoring & Evaluation Platforms (Drift, Quality, Safety) (HDAEANAF)
- akta.pro secondary industry
- AI Benchmarking, Profiling & Performance Monitoring (HDAAAAAJ)
Keywords
Where neptune.ai is headquartered
LocationHeadquarters
- HQ city
- Palo Alto
- HQ country
- United States
- HQ region
- North America
Offices1 record
Markets served
neptune.ai business model
Business model- GTM type
- B2B
- Offering type
- Software
- Cost components
- Personnel, Technology or R&D, Infrastructure, Marketing or Sales, Operations
Revenue model
- SaaS Subscription: Neptune.ai operated as a hosted SaaS platform offering experiment tracking and model training monitoring services. The company offered pricing plans with tiers including free tiers and custom enterprise plans based on usage and features. The hosted platform was set to wind down by March 5, 2026 as part of the OpenAI acquisition.
Pricing tiers
| Model | Billing | Price |
|---|---|---|
| Freemium | Monthly | Free tier available |
| Subscription | Annual | Custom enterprise plans |
Go-to-market motion1 record
Distribution channels2 records
Marketing channels3 records
neptune.ai product offering
Product offeringCore offering
Neptune.ai provided a hosted SaaS ML experiment tracking and model training observability platform that enabled AI researchers and ML engineers to log metrics, parameters, and model artifacts during training runs, monitor training in real time, compare thousands of runs, and analyze metrics across model layers. The service was delivered through a web dashboard and a Python client library (neptune-client) integrated with popular ML frameworks including TensorFlow, PyTorch, and Scikit-learn.
Product overview
Neptune.ai is a specialized ML experiment tracking and model training observability platform offered as a unified SaaS product. The platform consists of a hosted Neptune.ai service (web dashboard and API) integrated with a Python client library (neptune-client) that ML practitioners use within their training scripts. The product focuses on experiment tracking, metrics logging, and training run monitoring to help organizations improve scalability and reduce time-to-market for AI solutions. Following its acquisition by OpenAI in December 2025, the external hosted platform was scheduled to wind down, with the technology being integrated exclusively into OpenAI's internal training infrastructure.
Differentiator
Problem solved
Functional benefit
Products and services
- Neptune.ai Experiment Tracking Platform Hosted SaaS platform for ML experiment tracking and model training observability that enables AI researchers and ML engineers to log metrics, parameters, and model artifacts; monitor training in real time; compare thousands of runs; and analyze metrics across model layers, with integrations for TensorFlow, PyTorch, and Scikit-learn.
Companies that use neptune.ai
Customer profileNamed customers3 records
Segments2 records
Ideal customer profiles2 records
neptune.ai technology and API
TechnologyTechnology focussed Yes
API detail
- Has API
- Yes
- API docs
- API detail
Core technology
AI maturity
App detail
AI capability4 records
Feature3 records
neptune.ai partnerships and signals
Strategic signalPartnerships
One partnership is on record.
- OpenAIflagshipOpenAI acquired Neptune.ai to integrate its experiment tracking and training monitoring tools into OpenAI's training infrastructure. The acquisition aims to strengthen OpenAI's research infrastructure by providing deeper visibility into frontier model training. Neptune's tools were already in use at OpenAI for over a year before the acquisition. Neptune will phase out external services by March 2026, with the technology to be used exclusively internally at OpenAI.
Scale indicators5 records
Recent moves7 records
Expansion highlights3 records
neptune.ai competitors and assessment
Company assessmentDirect peers
- Weights & Biases: Weights & Biases is the most direct competitor to Neptune.ai, offering experiment tracking, model training monitoring, and metrics dashboards for ML teams, with the same TensorFlow/PyTorch integrations and PLG GTM motion.
- MLflow: MLflow is the open-source experiment tracking and model lifecycle platform originally created by Databricks. It is a direct functional peer to Neptune's experiment tracking, with comparable use cases for ML researchers.
- Comet: Comet provides experiment tracking, model monitoring, and ML observability tools for data scientists, with a SaaS delivery model and self-serve/enterprise tiers that closely mirror Neptune's offering.
- ClearML: ClearML is an open-source MLOps platform offering experiment tracking, orchestration, and model management, positioning it as a directly comparable alternative to Neptune for ML teams.
Emerging players
- Aim (aimstack): Aim is an open-source experiment tracking tool focused on AI/ML researchers. It overlaps meaningfully with Neptune's core use case of comparing thousands of runs and tracking metrics, though with a smaller commercial footprint.
- TensorBoard: TensorBoard is the default visualization and tracking tool for TensorFlow and increasingly other frameworks. It addresses overlapping needs to Neptune's training monitoring and metrics dashboard, but ships free as part of the TensorFlow ecosystem.
- Iterative (DVC / Studio): Iterative.ai provides DVC for ML experiment tracking and data versioning, along with its managed Studio product, positioning it as a comparable tool for ML experiment management and model development workflows.
- Arize AI: Arize AI focuses on ML observability and model monitoring in production. While Neptune focused on training observability and Arize on inference/eval, both sit in the AI observability and evaluation category targeting ML practitioners.
Broad incumbents
- Databricks: Databricks is a broad data and AI platform that owns MLflow and bundles experiment tracking, model training, and deployment. It competes with Neptune indirectly by offering overlapping ML lifecycle capabilities as part of a much larger platform.
- Domino Data Lab: Domino provides an enterprise MLOps platform with experiment tracking, model development, and deployment. It overlaps with Neptune's experiment tracking and training monitoring use cases, with a stronger enterprise/regulated-industry focus.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat4 records
Key risks5 records
Key highlights6 records
Customer concentration
neptune.ai social profiles
Digital presenceneptune.ai financial estimates
Financial estimateRevenue estimate
Valuation estimate
neptune.ai leadership team
Management profileNumber of profiles
Profiles1 record
neptune.ai funding detail
Funding detailFunding overview
Funding rounds3 records
Investors4 records
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
neptune.ai M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about neptune.ai
What does neptune.ai do?
Neptune.ai provided a hosted SaaS ML experiment tracking and model training observability platform that enabled AI researchers and ML engineers to log metrics, parameters, and model artifacts during training runs, monitor training in real time, compare thousands of runs, and analyze metrics across model layers. The service was delivered through a web dashboard and a Python client library (neptune-client) integrated with popular ML frameworks including TensorFlow, PyTorch, and Scikit-learn.
Is neptune.ai a public or private company?
neptune.ai is a private company. It is classified as venture growth investor backed and is currently acquired.
When was neptune.ai founded?
neptune.ai was founded in 2018. It employs 51 to 100 people.
Where is neptune.ai based?
neptune.ai is headquartered in Palo Alto, United States, in the North America region.
How does neptune.ai make money?
One revenue line is on record: saaS Subscription.
Who are neptune.ai's main competitors?
Direct peers on record are Weights & Biases, MLflow, Comet and ClearML. Emerging players are Aim (aimstack), TensorBoard, Iterative (DVC / Studio) and Arize AI. Broad incumbents are Databricks and Domino Data Lab.
Does neptune.ai have an API?
Yes. Neptune.ai provides a Python client library (neptune-client) for integrating experiment tracking into ML workflows. The client allows users to log metrics, parameters, and model artifacts during training runs. Developer documentation is at docs.neptune.ai.
What industry is neptune.ai in?
neptune.ai's product category is MLOps and AI Training Observability Software. Its primary akta.pro industry code is HDAEANAF, AI Observability, Monitoring & Evaluation Platforms (Drift, Quality, Safety), with a secondary code of HDAAAAAJ, AI Benchmarking, Profiling & Performance Monitoring. Its NAICS code is 54151 and its SIC code is 7372.