B12 website screenshot

B12

B12 is an AI-powered website builder that generates professional websites, online stores, and web apps from a short prompt. Founded on a human-in-the-loop model and now driven by its B12 3.0 AI Agent (launched February 2026), the platform lets solopreneurs, consultants, freelancers, and growing teams describe a business idea and launch a site in minutes, then run that business online with built-in tools for SEO, online payments and invoicing, scheduling, email marketing, client intake, contact management, and contracts with eSignatures. B12 offers self-serve DIY plans as well as Expert plans where its design and content team handles setup and ongoing updates. Over 4 million websites have been built on B12. B12 exposes its website-generation capability to AI agents through two live, anonymous, remote Model Context Protocol (MCP) endpoints, two provider-published Claude Agent Skills, and a Website Generator GPT, but publishes no general-purpose public REST API, no OpenAPI, and no developer portal.

B12 publishes 1 API on the APIs.io network. Tagged areas include Company, Enterprise, Website Builder, AI, and No-Code.

B12’s developer surface includes support, engineering blog, pricing, signup flow, authentication, and 18 more developer resources.

32.7/100 thin ▲ 13.8 Agent 34/100 agent aware Full breakdown ↓
scored 2026-08-17 · rubric v0.11.0
1 APIs 1 MCP Servers
CompanyEnterpriseWebsite BuilderAINo-CodeSmall BusinessWebsite GenerationModel Context ProtocolSEOPayments

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-17 · rubric v0.11.0
Composite quality — 32.7/100 · thin
Contract Quality 0.0 / 21
Developer Ergonomics 5.5 / 17
Commercial Clarity 13.0 / 17
Operational Transparency 0.6 / 11
Governance 1.3 / 10
Discoverability 6.5 / 9
Regulatory Posture 5.9 / 15
Agent readiness — 34/100 · agent aware
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 10
MCP Server 12 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 8 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 5 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 3 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Regulatory Posture applies to this provider. Its tags matched the Payments 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.
The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/b12: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 1

Individual APIs this provider publishes, each with its own machine-readable definition.

B12 Website Generator MCP Server

B12's Model Context Protocol server, and the only machine-callable surface B12 publishes. It exposes a single tool, generate_website, which builds a website draft with AI from a...

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

b12-mcp.yml

MCP SERVER

Pricing Plans 1

Published pricing tiers and plan structures.

B12 Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

B12 Rate Limits

0 limits

RATE LIMITS

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

B12 Authentication

none · 2 schemes

SECURITY

B12 Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

Build 2

SDKs, sample code, and the tooling you integrate with

Access & Security 2

Authentication, authorization, and security posture

Operate 3

Status, limits, changes, and where to get help

Commercial 4

Pricing, plans, and the legal terms of use

Company 2

The organization behind the API

Other 1

Properties that don't map to a standard resource type

Source (apis.yml)

apis.yml Raw ↑
aid: b12
name: B12
description: B12 is an AI-powered website builder that generates professional websites, online stores, and web apps from a
  short prompt. Founded on a human-in-the-loop model and now driven by its B12 3.0 AI Agent (launched February 2026), the
  platform lets solopreneurs, consultants, freelancers, and growing teams describe a business idea and launch a site in minutes,
  then run that business online with built-in tools for SEO, online payments and invoicing, scheduling, email marketing, client
  intake, contact management, and contracts with eSignatures. B12 offers self-serve DIY plans as well as Expert plans where
  its design and content team handles setup and ongoing updates. Over 4 million websites have been built on B12. B12 exposes
  its website-generation capability to AI agents through two live, anonymous, remote Model Context Protocol (MCP) endpoints,
  two provider-published Claude Agent Skills, and a Website Generator GPT, but publishes no general-purpose public REST API,
  no OpenAPI, and no developer portal.
url: https://raw.githubusercontent.com/api-evangelist/b12/refs/heads/main/apis.yml
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://www.b12.io/static-assets/images/ai-website-builder.jpeg
x-type: company
x-source: vc-portfolio
x-backed-by:
- general-catalyst
x-tier: enriched
x-tier-reason: live MCP surface probed; provider-published skills, llms.txt and packages harvested
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-08-13'
tags:
- Company
- Enterprise
- Website Builder
- AI
- No-Code
- Small Business
- Website Generation
- Model Context Protocol
- SEO
- Payments
apis:
- name: B12 Website Generator MCP Server
  description: 'B12''s Model Context Protocol server, and the only machine-callable surface B12 publishes. It exposes a single
    tool, generate_website, which builds a website draft with AI from a business name, description, image keywords and subtitle,
    then returns a static preview image and a signup link to claim and edit the site. Two remote deployments run in parallel:
    mcp.b12.io/mcp serves Claude with an MCP-UI preview resource, and b12.io/mcp serves ChatGPT Apps. Both answer anonymously
    with no API key, token or OAuth challenge.'
  humanURL: https://github.com/b12io/website-generator-mcp-server
  baseURL: https://mcp.b12.io/mcp
  tags:
  - Model Context Protocol
  - Website Generation
  - AI
  properties:
  - type: MCPServer
    url: mcp/b12-mcp.yml
  - type: Authentication
    url: authentication/b12-authentication.yml
  - type: ErrorCatalog
    url: errors/b12-problem-types.yml
  - type: Conventions
    url: conventions/b12-conventions.yml
  - type: RateLimits
    url: rate-limits/b12-rate-limits.yml
  - type: SourceCode
    url: https://github.com/b12io/website-generator-mcp
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://www.b12.io
- type: MCPServer
  name: B12 Website Generator MCP Server
  url: mcp/b12-mcp.yml
- type: LLMsTxt
  url: llms/b12-llms.txt
- type: DomainSecurity
  url: security/b12-domain-security.yml
- type: GitHubOrganization
  url: https://github.com/b12io
- type: HelpCenter
  url: https://support.b12.io/en
- type: Support
  url: https://www.b12.io/support/
- type: Blog
  url: https://www.b12.io/resource-center/
- type: Pricing
  url: https://www.b12.io/pricing/
- type: SignUp
  url: https://b12.io/signup/
- type: TermsOfService
  url: https://www.b12.io/terms-of-service/
- type: PrivacyPolicy
  url: https://www.b12.io/privacy-policy/
- type: Packages
  url: packages/b12-packages.yml
- type: AgentSkill
  name: B12 Claude Agent Skills (provider-published)
  url: skills/_index.yml
- type: Authentication
  url: authentication/b12-authentication.yml
- type: ErrorCatalog
  url: errors/b12-problem-types.yml
- type: Conventions
  url: conventions/b12-conventions.yml
- type: Conformance
  url: conformance/b12-conformance.yml
- type: Lifecycle
  url: lifecycle/b12-lifecycle.yml
- type: Components
  url: components/b12-components.yml
- type: RateLimits
  url: rate-limits/b12-rate-limits.yml
- type: Plans
  url: plans/b12-plans-pricing.yml
- type: ContentSignal
  name: Content Signals declaration in robots.txt (ai-train=yes, search=yes, ai-input=yes)
  url: well-known/b12-robots.txt
x-enrichment:
  date: '2026-08-13'
  status: enriched
  artifacts_added: 12
  pass: local-v1
x-coverage:
  state: covered
  note: 'B12 has no REST API and no OpenAPI, but it is not a thin profile: its agent surface is real, live and fully probeable.
    Two anonymous remote MCP endpoints returned complete tool schemas, and B12 publishes its own Agent Skills, an llms.txt
    and a Content Signals declaration.'
  checked: '2026-08-13'