Sigstore

Sigstore is a set of free-to-use open source tools for signing, verifying, and protecting software supply chain artifacts. It provides a transparent and auditable signing infrastructure that eliminates the need for managing signing keys, making software supply chain security more accessible. The Sigstore ecosystem includes Cosign for artifact signing, Fulcio as the certificate authority, and Rekor as the cryptographically secure transparency log.

Sigstore publishes 5 APIs on the APIs.io network, including CA API, entries API, index API, and 2 more. Tagged areas include Certificate Authority, Code Signing, Containers, Cryptography, and Open-Source.

The Sigstore catalog on APIs.io includes 1 JSON-LD context and 2 Spectral governance rulesets.

Sigstore’s developer surface includes documentation, getting-started guide, engineering blog, and 14 more developer resources.

🌐 Visit website 📡 Source on GitHub

36.5/100 thin ▬ flat Agent 17/100 agent aware self hosted · Apache-2.0 Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessPaid

2 APIs

Certificate Authority Code Signing Containers Cryptography Open-Source PKI Security Software Supply Chain Transparency Log

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 36.5/100 · thin

Contract Quality 10.0 / 20

Developer Ergonomics 4.2 / 16

Access Clarity 2.1 / 16

Operational Transparency 3.6 / 10

Contract Governance 2.8 / 10

Discoverability 4.7 / 8

Open Source Surface 6.5 / 10

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 17/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 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

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 80 points between them, because the conditional facet above carries the other 20. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 80% 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/. 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 github.com/api-evangelist/sigstore: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 6

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

Cosign

Cosign is the Sigstore tool for signing and verifying container images and other OCI artifacts. It enables keyless signing using OIDC identity, hardware token signing, and polic...

Sigstore CA API

The CA API from Sigstore — 3 operation(s) for ca.

Sigstore entries API

The entries API from Sigstore — 3 operation(s) for entries.

Sigstore index API

The index API from Sigstore — 1 operation(s) for index.

Sigstore pubkey API

The pubkey API from Sigstore — 1 operation(s) for pubkey.

Sigstore tlog API

The tlog API from Sigstore — 2 operation(s) for tlog.

Open Collections 7

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

API Collection

OPEN COLLECTION

Fulcio

OPEN COLLECTION

Fulcio CA API

OPEN COLLECTION

Fulcio CA entries API

OPEN COLLECTION

Fulcio CA index API

OPEN COLLECTION

Fulcio CA pubkey API

OPEN COLLECTION

Fulcio CA tlog API

OPEN COLLECTION

Scroll for all 7

Pricing Plans 1

Published pricing tiers and plan structures.

Sigstore Plans Pricing

1 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Sigstore Rate Limits

1 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Sigstore Finops

FINOPS

Semantic Vocabularies 1

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

Sigstore Context

30 classes · 2 properties

JSON-LD

Spectral Rules 2

Spectral governance rulesets for linting and validating these APIs.

Sigstore API Rules

5 rules · 3 warnings 2 info

SPECTRAL

Sigstore API Rules

6 rules · 1 errors 5 warnings

SPECTRAL

JSON Schema 2

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

Sigstore Fulcio Signing Certificate

2 properties

JSON SCHEMA

Sigstore Rekor Log Entry

6 properties

JSON SCHEMA

JSON Structure 1

JSON Structure definitions describing this provider's data shapes.

Sigstore Log Entry Structure

0 properties

JSON STRUCTURE

Examples 3

Example request and response payloads for these APIs.

Sigstore Create Log Entry Example

3 fields

EXAMPLE

Sigstore Get Signing Cert Example

3 fields

EXAMPLE

Sigstore Search Log Index Example

3 fields

EXAMPLE

Security Posture 1

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

Sigstore Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

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

Sigstore Agentic Access

11 operations · 4 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

ContributionGuide

ContributionGuide

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Vocabulary

Vocabulary

Build 2

SDKs, sample code, and the tooling you integrate with

CodeOfConduct

CodeOfConduct

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Security

Security

Operate 3

Status, limits, changes, and where to get help

IssueTracker

IssueTracker

Releases

Releases

Community

Community

Commercial 1

Pricing, plans, and the legal terms of use

License

License

Company 3

The organization behind the API

LinkedIn

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Policy Controller

Policy Controller

Source (apis.yml)

aid: sigstore
name: Sigstore
description: Sigstore is a set of free-to-use open source tools for signing, verifying, and protecting software supply chain
  artifacts. It provides a transparent and auditable signing infrastructure that eliminates the need for managing signing
  keys, making software supply chain security more accessible. The Sigstore ecosystem includes Cosign for artifact signing,
  Fulcio as the certificate authority, and Rekor as the cryptographically secure transparency log.
type: Index
deliveryModel:
  model: self-hosted
  license: Apache-2.0
  open_source: true
  commercial: false
  callable_host: true
  label: Self-hosted open source · you run it yourself
  confidence: high
  source:
  - license
  - openapi
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: paid
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Paid
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/sigstore.png
tags:
- Certificate Authority
- Code Signing
- Containers
- Cryptography
- Open-Source
- PKI
- Security
- Software Supply Chain
- Transparency Log
tags_raw:
- Certificate Authority
- Code Signing
- Containers
- Cryptography
- Open Source
- PKI
- Security
- Software Supply Chain
- Transparency Log
url: https://raw.githubusercontent.com/api-evangelist/sigstore/refs/heads/main/apis.yml
created: '2026-03-26'
modified: '2026-05-19'
specificationVersion: '0.23'
apis:
- aid: sigstore:cosign
  name: Cosign
  description: Cosign is the Sigstore tool for signing and verifying container images and other OCI artifacts. It enables
    keyless signing using OIDC identity, hardware token signing, and policy enforcement for container supply chain security.
  humanURL: https://docs.sigstore.dev/cosign/signing/overview/
  tags:
  - Code Signing
  - Containers
  - OCI
  - Security
  - Software Supply Chain
  properties:
  - type: Documentation
    url: https://docs.sigstore.dev/cosign/signing/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/cosign
- aid: sigstore:sigstore-ca-api
  name: Sigstore CA API
  description: The CA API from Sigstore — 3 operation(s) for ca.
  humanURL: https://docs.sigstore.dev/logging/overview/
  baseURL: https://rekor.sigstore.dev
  tags:
  - CA
  properties:
  - type: OpenAPI
    url: openapi/sigstore-ca-api-openapi.yml
  - type: Documentation
    url: https://docs.sigstore.dev/logging/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/rekor
  - type: Rules
    url: https://raw.githubusercontent.com/api-evangelist/sigstore/refs/heads/main/rules/sigstore-rules.yml
  - type: Documentation
    url: https://docs.sigstore.dev/certificate_authority/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/fulcio
- aid: sigstore:sigstore-entries-api
  name: Sigstore entries API
  description: The entries API from Sigstore — 3 operation(s) for entries.
  humanURL: https://docs.sigstore.dev/logging/overview/
  baseURL: https://rekor.sigstore.dev
  tags:
  - Entries
  tags_raw:
  - entries
  properties:
  - type: OpenAPI
    url: openapi/sigstore-entries-api-openapi.yml
  - type: Documentation
    url: https://docs.sigstore.dev/logging/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/rekor
  - type: Rules
    url: https://raw.githubusercontent.com/api-evangelist/sigstore/refs/heads/main/rules/sigstore-rules.yml
  - type: Documentation
    url: https://docs.sigstore.dev/certificate_authority/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/fulcio
- aid: sigstore:sigstore-index-api
  name: Sigstore index API
  description: The index API from Sigstore — 1 operation(s) for index.
  humanURL: https://docs.sigstore.dev/logging/overview/
  baseURL: https://rekor.sigstore.dev
  tags:
  - Index
  tags_raw:
  - index
  properties:
  - type: OpenAPI
    url: openapi/sigstore-index-api-openapi.yml
  - type: Documentation
    url: https://docs.sigstore.dev/logging/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/rekor
  - type: Rules
    url: https://raw.githubusercontent.com/api-evangelist/sigstore/refs/heads/main/rules/sigstore-rules.yml
  - type: Documentation
    url: https://docs.sigstore.dev/certificate_authority/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/fulcio
- aid: sigstore:sigstore-pubkey-api
  name: Sigstore pubkey API
  description: The pubkey API from Sigstore — 1 operation(s) for pubkey.
  humanURL: https://docs.sigstore.dev/logging/overview/
  baseURL: https://rekor.sigstore.dev
  tags:
  - Pubkey
  tags_raw:
  - pubkey
  properties:
  - type: OpenAPI
    url: openapi/sigstore-pubkey-api-openapi.yml
  - type: Documentation
    url: https://docs.sigstore.dev/logging/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/rekor
  - type: Rules
    url: https://raw.githubusercontent.com/api-evangelist/sigstore/refs/heads/main/rules/sigstore-rules.yml
  - type: Documentation
    url: https://docs.sigstore.dev/certificate_authority/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/fulcio
- aid: sigstore:sigstore-tlog-api
  name: Sigstore tlog API
  description: The tlog API from Sigstore — 2 operation(s) for tlog.
  humanURL: https://docs.sigstore.dev/logging/overview/
  baseURL: https://rekor.sigstore.dev
  tags:
  - tlog
  properties:
  - type: OpenAPI
    url: openapi/sigstore-tlog-api-openapi.yml
  - type: Documentation
    url: https://docs.sigstore.dev/logging/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/rekor
  - type: Rules
    url: https://raw.githubusercontent.com/api-evangelist/sigstore/refs/heads/main/rules/sigstore-rules.yml
  - type: Documentation
    url: https://docs.sigstore.dev/certificate_authority/overview/
  - type: GitHubRepository
    url: https://github.com/sigstore/fulcio
common:
- type: IssueTracker
  url: https://github.com/sigstore/cosign/issues
- type: Releases
  url: https://github.com/sigstore/cosign/releases
- type: CodeOfConduct
  url: https://github.com/sigstore/cosign/blob/main/CODE_OF_CONDUCT.md
- type: ContributionGuide
  url: https://github.com/sigstore/cosign/blob/main/CONTRIBUTING.md
- type: License
  name: Apache-2.0
  url: https://github.com/sigstore/cosign/blob/main/LICENSE
- type: AgenticAccess
  url: agentic-access/sigstore-agentic-access.yml
- type: DomainSecurity
  url: security/sigstore-domain-security.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/sigstore
- type: Website
  url: https://www.sigstore.dev/
- type: Documentation
  url: https://docs.sigstore.dev/
- type: GettingStarted
  url: https://docs.sigstore.dev/quickstart/quickstart-cosign/
- type: GitHubOrganization
  url: https://github.com/sigstore
- type: Blog
  url: https://blog.sigstore.dev/
- type: Community
  url: https://sigstore.dev/community/
- type: Policy Controller
  url: https://docs.sigstore.dev/policy-controller/overview/
- type: Security
  url: https://docs.sigstore.dev/about/security/
- type: Vocabulary
  url: https://raw.githubusercontent.com/api-evangelist/sigstore/refs/heads/main/vocabulary/sigstore-vocabulary.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for providers

9 MCP tools reach this

find_providersBrowse and filter every provider in the catalog.
get_provider_artifactsEvery artifact this provider publishes, grouped by type.
get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
get_provider_ratingPRO — composite, band, trend and facet scores.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This provider

curl "https://apis.io/api/v1/providers/sigstore"

All providers

curl "https://apis.io/api/v1/providers?limit=25"

Every operation they expose

curl "https://apis.io/api/v1/providers/sigstore/operations?limit=25"

How their score was established

curl "https://apis.io/api/v1/providers/sigstore/evidence"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.