0s and 1s

0s and 1s provides free CIS (Construction Industry Scheme) software for UK contractors, offering tools to verify subcontractors, record payments, file CIS300 returns, send statements, and calculate deductions and penalties. The platform runs on a free API and MCP server, integrates with HMRC data, and is operated by Voll Studios Ltd. It aims to simplify contractor payroll compliance and reporting.

0s and 1s publishes 1 API contract indexed on the APIs.io network: CIS API. Tagged areas include Construction, Payroll, Tax, United Kingdom, and Software.

The 0s and 1s catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

0s and 1s’ developer surface includes documentation, API reference, getting-started guide, support, pricing, and 26 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

53.0/100 developing ▬ flat Agent 39/100 agent ready Full breakdown ↓
scored 2026-11-02 · rubric v0.26.0 · Show this score on your site →

AccessPaidOpen

1 published contract 1 MCP Servers 7 Agent Skills

Construction Payroll Tax United Kingdom Software CIS

Kin Score

Kin Score How this is scored →
scored 2026-11-02 · rubric v0.26.0

Composite quality — 53.0/100 · developing

Contract Quality 12.5 / 21

Developer Ergonomics 8.4 / 17

Access Clarity 11.2 / 17

Operational Transparency 3.5 / 11

Contract Governance 2.0 / 10

Discoverability 5.5 / 9

Regulatory Posture 5.1 / 15

Agent readiness — 39/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 5

Well-Known Catalog 4 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 0 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Employment & Payroll 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.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

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/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Machine-Readable Auth +10 pts — a served openid-configuration/oauth-authorization-server carrying `issuer` (served), else the securitySchemes class in the provider OpenAPIs — bound (mutualTLS, DPoP, Signature) > negotiable (oauth2 authorizationCode/clientCredentials, openIdConnect) > bearer (http bearer, apiKey)
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
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
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

6 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 58.7 — up to +10.3 composite points
Developer Ergonomics scores 49.3 — up to +10.1 composite points
Contract Governance scores 19.7 — up to +9.6 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/0sand1s-co-uk/apis.yml: open an issue on github.com/api-evangelist/0sand1s-co-uk to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Standards implemented 1

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.

OpenAPI

measured — observed by APIs.io (published)

APIs 1

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

0s and 1s CIS API

The CIS API from 0s and 1s — 7 operation(s) for cis.

MCP Servers 1

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

0s and 1s MCP Server

Remote MCP server at 0sand1s.co.uk.

MCP SERVER

Agent Skills 7

Packaged agent skills for driving this provider's APIs from an AI assistant.

cis-deduction

AGENT SKILL

cis-gross-payment-turnover-test

AGENT SKILL

cis-gross-up

AGENT SKILL

cis-late-penalties

AGENT SKILL

cis-needs-verification

AGENT SKILL

cis-nil-return-check

AGENT SKILL

cis-tax-month

AGENT SKILL

Scroll for all 7

Pricing Plans 1

Published pricing tiers and plan structures.

0Sand1S Co Uk Plans Pricing

2 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

0Sand1S Co Uk Rate Limits

1 limits

RATE LIMITS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

0Sand1S Co Uk Context

3 classes · 10 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

0s and 1s API Rules

16 rules · 15 errors 1 info

SPECTRAL

OpenAPI Overlays 1

Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.

0Sand1S Co Uk Openapi Overlay

0 actions · update

UNRECORDED

JSON Schema 1

Standalone JSON Schema definitions for this provider's data models.

ToolResponse

5 properties

JSON SCHEMA

Security Posture 3

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

0Sand1S Co Uk Authentication

0 schemes

SECURITY

0Sand1S Co Uk Domain Security

TLSv1.3 · HSTS

SECURITY

0Sand1S Co Uk Vulnerability Disclosure

security.txt · contact published

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

0Sand1S Co Uk Scopes

OAuth 2.0 · no documented scopes

0 scopes

SCOPES

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

0Sand1S Co Uk Agentic Access

14 operations · 7 acting

AGENTIC

Resources

Get Started 3

Portal, sign-up, and the first successful call

Login

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 5

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgentSkill

LLMsTxt

MCPServer

WellKnown

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Spectral

JSONLD

Vocabulary

DataModel

Conventions

ErrorCatalog

Conformance

Scroll for all 7

Build 1

SDKs, sample code, and the tooling you integrate with

ToolCrosswalk

ToolCrosswalk

Access & Security 4

Authentication, authorization, and security posture

SecurityTxt

SecurityTxt

Security

Security

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

RateLimits

RateLimits

Support

Support

Commercial 4

Pricing, plans, and the legal terms of use

Plans

Pricing

TermsOfService

PrivacyPolicy

Company 1

The organization behind the API

Website

Website

Other 2

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: 0sand1s-co-uk
name: 0s and 1s
description: 0s and 1s provides free CIS (Construction Industry Scheme) software for UK contractors, offering tools to verify
  subcontractors, record payments, file CIS300 returns, send statements, and calculate deductions and penalties. The platform
  runs on a free API and MCP server, integrates with HMRC data, and is operated by Voll Studios Ltd. It aims to simplify contractor
  payroll compliance and reporting.
accessModel:
  pricing: paid
  onboarding: open
  trial: false
  try_now: false
  public: true
  gated: none
  gated_source:
  - onboarding
  label: Paid · Open access
  confidence: high
  source:
  - plans
  - authentication
  - rate-limits
  - security
  generated: '2026-11-02'
  method: derived
image: https://0sand1s.co.uk/brand/logo.svg
url: https://artifacts.apis.io/0sand1s-co-uk/apis.yml
x-type: company
x-source: harvest:mcp-registry
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-31 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-31'
modified: '2026-10-31'
tags:
- Construction
- Payroll
- Tax
- United Kingdom
- Software
- CIS
tags_raw:
- Construction
- Payroll
- Tax
- UK
- Software
- CIS
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: AgenticAccess
  url: agentic-access/0sand1s-co-uk-agentic-access.yml
- type: RateLimits
  url: rate-limits/0sand1s-co-uk-rate-limits.yml
- type: Plans
  url: plans/0sand1s-co-uk-plans-pricing.yml
- type: Spectral
  url: rules/0sand1s-co-uk-rules.yml
- type: JSONLD
  url: json-ld/0sand1s-co-uk-context.jsonld
- type: Vocabulary
  url: vocabulary/0sand1s-co-uk-vocabulary.yml
- type: AgentSkill
  url: skills/_index.yml
- type: DataModel
  url: data-model/0sand1s-co-uk-data-model.yml
- type: Conventions
  url: conventions/0sand1s-co-uk-conventions.yml
- type: ErrorCatalog
  url: errors/0sand1s-co-uk-problem-types.yml
- type: Conformance
  url: conformance/0sand1s-co-uk-conformance.yml
- type: LLMsTxt
  url: llms/0sand1s-co-uk-llms.txt
- type: ToolCrosswalk
  url: mcp/0sand1s-co-uk-tool-crosswalk.yml
- type: MCPServer
  url: mcp/0sand1s-co-uk-mcp.yml
- type: SecurityTxt
  url: well-known/0sand1s-co-uk-security.txt
- type: WellKnown
  url: well-known/0sand1s-co-uk-well-known.yml
- type: Hosts
  url: hosts/0sand1s-co-uk-hosts.yml
- type: Vendors
  url: vendors/0sand1s-co-uk-vendors.yml
- type: Security
  url: https://0sand1s.co.uk/security
- type: Login
  url: https://0sand1s.co.uk/sign-in
- type: VulnerabilityDisclosure
  url: security/0sand1s-co-uk-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/0sand1s-co-uk-domain-security.yml
- type: Website
  url: https://0sand1s.co.uk/
- type: DeveloperPortal
  url: https://0sand1s.co.uk/developers
- type: Documentation
  url: https://0sand1s.co.uk/developers
- type: APIReference
  url: https://0sand1s.co.uk/api/v1/openapi.json
- type: GettingStarted
  url: https://0sand1s.co.uk/guides/free-cis-software
- type: Support
  url: https://0sand1s.co.uk/contact
- type: Pricing
  url: https://0sand1s.co.uk/pricing
- type: TermsOfService
  url: https://0sand1s.co.uk/terms
- type: PrivacyPolicy
  url: https://0sand1s.co.uk/privacy
apis:
- aid: 0sand1s-co-uk:0sand1s-co-uk-cis-api
  name: 0s and 1s CIS API
  description: The CIS API from 0s and 1s — 7 operation(s) for cis.
  humanURL: https://0sand1s.co.uk/developers
  baseURL: https://0sand1s.co.uk
  tags:
  - CIS
  properties:
  - type: OpenAPI
    url: openapi/0sand1s-co-uk-cis-api-openapi.yml
  - type: JSONSchema
    url: json-schema/0sand1s-co-uk-tool-response-schema.json
x-enrichment:
  date: '2026-10-31'
  status: enriched
  artifacts_added: 42
  pass: modular-v1
  engine: identity=oss,contract=oss,surfaces=oss,docs=oss,regulatory=oss

0s and 1s API — frequently asked questions

Does 0s and 1s have an API?

Yes. APIs.io lists 1 API from 0s and 1s, including 0s and 1s CIS API.

Is there an OpenAPI specification for the 0s and 1s API?

Yes. APIs.io indexes 1 OpenAPI specification for 0s and 1s, each linked for download from this page.

How do I authenticate with the 0s and 1s API?

0s and 1s documents its authentication (0 schemes). The details are profiled on APIs.io as 0Sand1S Co Uk Authentication.

How much does the 0s and 1s API cost?

APIs.io lists 2 pricing plans for 0s and 1s, with each plan's price, limits and inclusions under Pricing Plans on this page.

Does 0s and 1s have an MCP server?

Yes. APIs.io lists 1 MCP server for 0s and 1s: Remote MCP server at 0sand1s.co.uk.

Is the 0s and 1s API ready for AI agents?

0s and 1s has a Kin Score of 53.0 out of 100 (developing) and an Agent Readiness score of 39.3 (agent-ready), scored by API Evangelist on 2026-11-02.

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