Weights and Biases (W&B) is an MLOps and AI developer platform covering the full lifecycle of model and LLM application development. W&B Models provides experiment tracking, hyperparameter sweeps, artifacts, model registry, and reports. W&B Weave provides LLM tracing, evaluation, cost tracking, guardrails, and prompt/playground tooling for production AI applications. Three CoreWeave- powered serverless capabilities sit alongside the core platform: Serverless Inference (OpenAI-compatible API for open-source foundation models), Serverless RL (post-training with ART/RULER), and Serverless Sandboxes (isolated code execution). The platform exposes a Python SDK, a public REST API, and a GraphQL API at api.wandb.ai, with CLI tooling and webhook integrations. W&B was acquired by CoreWeave in 2025.
Weights and Biases publishes 16 API contracts indexed on the APIs.io network, including Calls API, Costs API, Feedback API, and 13 more. Tagged areas include MLOps, Experiment Tracking, LLM Observability, Model Registry, and AI Platform.
The Weights and Biases catalog on APIs.io includes 1 Spectral governance ruleset.
Weights and Biases’ developer surface includes authentication, documentation, GitHub presence, pricing, engineering blog, and 18 more developer resources.
37.9/100thin▬ flatAgent34/100agent readyFront door AI6/6
dominant
Heartbeat95/100
alive
open core · Apache-2.0
Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →
Regulatory Posture applies to this provider. Its tags matched the
Horizontal (data, software, accessibility, platform) regime, so
Regulatory Posture carries 15 points of the composite.
If this regime is wrong for your business, say so on your
provider repo — the
applicability map is public and we will correct it.
Open Source Surface applies to this provider. This product is open source and we
read its repository directly, so Open Source Surface carries
10 points of the composite. It is scored from what the repository actually
publishes — a security policy, a contribution guide, a release history, a code of conduct — read live from the
provider rather than inferred from our own catalog pointers.
This facet adds; nothing was taken away to make room for it. An open-source project is not excused from
the commercial facets, because exemption would strip it of the points it does earn.
If we have the wrong repository, or this product is not open source, say so on your
provider repo and we
will drop the facet rather than have you publish against it.
Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it
carries 10 points of the composite. It is scored from the published contracts
themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already
holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in
front of it, and the first time that check is skipped a duplicate record is created.
Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet,
not penalised by it.
The six quality facets above are damped to 65 points between them,
because both conditional facets apply and carry
35 points together. That is why each facet's contribution is shown against a damped
maximum: raising a quality facet moves the composite by 65% of its nominal
weight, not 100%. The full arithmetic is at apis.io/rating/.
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Agent readiness — checks not met, largest first (exact, from this profile):
Idempotency+9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card+8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Request/Response Examples+7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link
Delegated User Identity+6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented)
Typed Event Surface+6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks
7 more unmet checks in the Agent Readiness table above.
Kin Score — facets with the most composite points still available (weight × headroom):
Access Clarityscores 15.8 — up to +16.8 composite points
The Kin Score Market layer reads a provider inside its market:
its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted:
not part of the Kin Score or agent readiness.
Registered MCP server and declares compatibility are report only — not weighted.
Undeclared means we found nothing we can read, so there is no number: we never infer integrations.
Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.
Primary programmatic surface for W&B Models. The Python public API (wandb.Api) speaks GraphQL against api.wandb.ai to query and manage runs, projects, sweeps, artifacts, registr...
REST endpoints exposed by the W&B platform for ingestion, artifact upload, file storage, and integration callbacks. Used internally by the wandb SDK and CLI, and available to cu...
LLM observability and evaluation platform providing tracing, output evaluation, cost estimation, prompt playground, guardrails, and a Python and TypeScript SDK. Traces and evalu...
Official Python SDK (wandb) for logging runs, metrics, gradients, media, and artifacts; running sweeps; and interacting with the W&B public API. Apache-2.0 licensed.
OpenAI-compatible inference API for hosted open-source foundation models, running on CoreWeave GPU infrastructure with native Weave tracing and usage tracking.
Outbound webhook integrations driven by W&B automations. Customers register endpoints that W&B POSTs to when configured events fire (artifact created, alias added, run state cha...
Primary programmatic surface for W&B Models. The Python public API (wandb.Api) speaks GraphQL against api.wandb.ai to query and manage runs, projects, sweeps, artifacts, registr...
GRAPHQL
Weights and Biases API pricing
Not yet checked against Weights and Biases's own pricing page. Compiled by API Evangelist on 2026-05-22; confirm before you rely on a figure. A free plan or tier is listed.
aid: wandb
url: https://raw.githubusercontent.com/api-evangelist/wandb/refs/heads/main/apis.yml
name: Weights and Biases
kind: company
description: 'Weights and Biases (W&B) is an MLOps and AI developer platform covering the full lifecycle of model and LLM
application development. W&B Models provides experiment tracking, hyperparameter sweeps, artifacts, model registry, and
reports. W&B Weave provides LLM tracing, evaluation, cost tracking, guardrails, and prompt/playground tooling for production
AI applications. Three CoreWeave- powered serverless capabilities sit alongside the core platform: Serverless Inference
(OpenAI-compatible API for open-source foundation models), Serverless RL (post-training with ART/RULER), and Serverless
Sandboxes (isolated code execution). The platform exposes a Python SDK, a public REST API, and a GraphQL API at api.wandb.ai,
with CLI tooling and webhook integrations. W&B was acquired by CoreWeave in 2025.'
deliveryModel:
model: open-core
license: Apache-2.0
open_source: true
commercial: true
callable_host: true
label: Open core · an OSS project plus a commercial hosted product
confidence: high
source:
- license
- openapi
- pricing
generated: '2026-08-28'
method: derived
accessModel:
pricing: free
onboarding: self-serve
trial: false
try_now: true
public: false
gated: none
gated_source:
- onboarding
label: Free · Self-serve signup
confidence: medium
source:
- plans
- authentication
- security
generated: '2026-11-06'
method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/wandb.png
x-docs-platform: mintlify
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-10-17
x-docs-hosting: cloudflare-pages
tags:
- MLOps
- Experiment Tracking
- LLM Observability
- Model Registry
- AI Platform
- Evaluation
- Tracing
created: '2026-05-23'
modified: '2026-05-23'
specificationVersion: '0.23'
apis:
- aid: wandb:graphql
name: W&B GraphQL API
description: Primary programmatic surface for W&B Models. The Python public API (wandb.Api) speaks GraphQL against api.wandb.ai
to query and manage runs, projects, sweeps, artifacts, registries, reports, automations, slack and webhook integrations,
and viewer/entity context.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- GraphQL
- Runs
- Artifacts
- Sweeps
- Model Registry
properties:
- type: Documentation
url: https://docs.wandb.ai/ref/python/public-api/api/
- url: graphql/wandb-graphql.md
type: GraphQL
- aid: wandb:rest
name: W&B REST API
description: REST endpoints exposed by the W&B platform for ingestion, artifact upload, file storage, and integration callbacks.
Used internally by the wandb SDK and CLI, and available to customers for direct integration.
humanURL: https://docs.wandb.ai/
baseURL: https://api.wandb.ai
tags:
- REST
- Ingestion
- Artifacts
properties:
- type: Documentation
url: https://docs.wandb.ai/
- aid: wandb:weave
name: W&B Weave (LLM Observability)
description: LLM observability and evaluation platform providing tracing, output evaluation, cost estimation, prompt playground,
guardrails, and a Python and TypeScript SDK. Traces and evaluations are persisted to the W&B backend and queryable via
the Weave SDK.
humanURL: https://weave-docs.wandb.ai/
baseURL: https://api.wandb.ai
tags:
- LLM
- Observability
- Tracing
- Evaluation
- Guardrails
properties:
- type: Documentation
url: https://weave-docs.wandb.ai/
- type: Repository
url: https://github.com/wandb/weave
- aid: wandb:python-sdk
name: W&B Python SDK
description: Official Python SDK (wandb) for logging runs, metrics, gradients, media, and artifacts; running sweeps; and
interacting with the W&B public API. Apache-2.0 licensed.
humanURL: https://docs.wandb.ai/ref/python/
baseURL: https://github.com/wandb/wandb
tags:
- SDK
- Python
properties:
- type: Repository
url: https://github.com/wandb/wandb
- type: Package
url: https://pypi.org/project/wandb/
- aid: wandb:cli
name: W&B CLI
description: Command-line interface bundled with the wandb Python package for login, sweep orchestration, artifact management,
and local agent execution.
humanURL: https://docs.wandb.ai/ref/cli/
baseURL: https://docs.wandb.ai/ref/cli/
tags:
- CLI
- Sweeps
- Agents
properties:
- type: Documentation
url: https://docs.wandb.ai/ref/cli/
- aid: wandb:serverless-inference
name: W&B Serverless Inference (CoreWeave)
description: OpenAI-compatible inference API for hosted open-source foundation models, running on CoreWeave GPU infrastructure
with native Weave tracing and usage tracking.
humanURL: https://docs.wandb.ai/guides/inference
baseURL: https://api.inference.wandb.ai/v1
tags:
- Inference
- OpenAI-Compatible
- LLM
- Serverless
properties:
- type: Documentation
url: https://docs.wandb.ai/guides/inference
- aid: wandb:webhook-automations
name: W&B Webhook Automations
description: Outbound webhook integrations driven by W&B automations. Customers register endpoints that W&B POSTs to when
configured events fire (artifact created, alias added, run state changes, registry events).
humanURL: https://docs.wandb.ai/guides/automations/
baseURL: customer-configured
tags:
- Webhook
- Automation
- Event
tags_raw:
- Webhooks
- Automations
- Events
properties:
- type: Documentation
url: https://docs.wandb.ai/guides/automations/
- aid: wandb:wandb-calls-api
name: Weights and Biases Calls API
description: The Calls API from Weights and Biases — 8 operation(s) for calls.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- Calls
properties:
- type: OpenAPI
url: openapi/wandb-calls-api-openapi.yml
- aid: wandb:wandb-costs-api
name: Weights and Biases Costs API
description: The Costs API from Weights and Biases — 3 operation(s) for costs.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- Costs
properties:
- type: OpenAPI
url: openapi/wandb-costs-api-openapi.yml
- aid: wandb:wandb-feedback-api
name: Weights and Biases Feedback API
description: The Feedback API from Weights and Biases — 4 operation(s) for feedback.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- Feedback
properties:
- type: OpenAPI
url: openapi/wandb-feedback-api-openapi.yml
- aid: wandb:wandb-files-api
name: Weights and Biases Files API
description: The Files API from Weights and Biases — 2 operation(s) for files.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- File
tags_raw:
- Files
properties:
- type: OpenAPI
url: openapi/wandb-files-api-openapi.yml
- aid: wandb:wandb-objects-api
name: Weights and Biases Objects API
description: The Objects API from Weights and Biases — 4 operation(s) for objects.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- Objects
properties:
- type: OpenAPI
url: openapi/wandb-objects-api-openapi.yml
- aid: wandb:wandb-refs-api
name: Weights and Biases Refs API
description: The Refs API from Weights and Biases — 1 operation(s) for refs.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- Refs
properties:
- type: OpenAPI
url: openapi/wandb-refs-api-openapi.yml
- aid: wandb:wandb-service-api
name: Weights and Biases Service API
description: The Service API from Weights and Biases — 2 operation(s) for service.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- Services
tags_raw:
- Service
properties:
- type: OpenAPI
url: openapi/wandb-service-api-openapi.yml
- aid: wandb:wandb-table-api
name: Weights and Biases Table API
description: The Table API from Weights and Biases — 1 operation(s) for table.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- Table
properties:
- type: OpenAPI
url: openapi/wandb-table-api-openapi.yml
- aid: wandb:wandb-tables-api
name: Weights and Biases Tables API
description: The Tables API from Weights and Biases — 4 operation(s) for tables.
humanURL: https://docs.wandb.ai/ref/python/public-api/api/
baseURL: https://api.wandb.ai/graphql
tags:
- Tables
properties:
- type: OpenAPI
url: openapi/wandb-tables-api-openapi.yml
common:
- type: CapabilityMap
url: capabilities/wandb-capability-edges.yml
name: Weights and Biases Business Capability Map
- type: ParentCompany
url: https://apis.io/providers/coreweave/
name: CoreWeave
x-relationship: acquired
x-evidence: W&B was acquired by CoreWeave in 2025.
- type: IssueTracker
url: https://github.com/wandb/weave/issues
- type: Releases
url: https://github.com/wandb/weave/releases
- type: SecurityPolicy
url: https://github.com/wandb/weave/blob/master/SECURITY.md
- type: ContributionGuide
url: https://github.com/wandb/weave/blob/master/CONTRIBUTING.md
- type: License
name: Apache-2.0
url: https://github.com/wandb/weave/blob/master/LICENSE
- type: AgenticAccess
url: agentic-access/wandb-agentic-access.yml
- type: VulnerabilityDisclosure
url: security/wandb-vulnerability-disclosure.yml
- type: DomainSecurity
url: security/wandb-domain-security.yml
- type: Authentication
url: authentication/wandb-authentication.yml
- type: LinkedIn
url: https://www.linkedin.com/company/wandbai
- type: Website
url: https://wandb.ai/
- type: Documentation
url: https://docs.wandb.ai/
- type: GitHub
url: https://github.com/wandb
- type: Weave
url: https://weave-docs.wandb.ai/
- type: Pricing
url: https://wandb.ai/site/pricing/
- type: Parent
url: https://www.coreweave.com/
- type: Plans
url: plans/wandb-plans-pricing.yml
- type: RateLimits
url: rate-limits/wandb-rate-limits.yml
- type: FinOps
url: finops/wandb-finops.yml
- type: LlmsText
url: https://docs.wandb.ai/llms.txt
- type: Blog
url: https://wandb.ai/fully-connected
integrations:
- name: PyTorch
- name: TensorFlow
- name: Hugging Face
- name: Keras
- name: scikit-learn
- name: OpenAI
- name: Anthropic
- name: LangChain
- name: LlamaIndex
- name: Slack
- name: GitHub
- name: Kubernetes
maintainers:
- FN: Kin Lane
email: kin@apievangelist.com
Weights and Biases API — frequently asked questions
Does Weights and Biases have an API?
Yes. APIs.io lists 16 APIs from Weights and Biases, including W&B GraphQL API, W&B REST API and W&B Weave (LLM Observability), and 13 more.
Is there an OpenAPI specification for the Weights and Biases API?
Yes. APIs.io indexes 9 OpenAPI specifications for Weights and Biases, each linked for download from this page.
How do I authenticate with the Weights and Biases API?
Weights and Biases uses bearer-token authentication (http · 1 scheme). The details are profiled on APIs.io as Wandb Authentication.
How much does the Weights and Biases API cost?
APIs.io lists 1 pricing plan for Weights and Biases, with each plan's price, limits and inclusions under Pricing on this page.
Does Weights and Biases have an MCP server?
Yes. APIs.io lists 1 MCP server for Weights and Biases: Remote MCP server at docs.wandb.ai over HTTP.
Is the Weights and Biases API ready for AI agents?
Weights and Biases has a Kin Score of 37.9 out of 100 (thin) and an Agent Readiness score of 33.7 (agent-ready), scored by API Evangelist on 2026-11-06.
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