Marginalia Search

Marginalia Search is an independent search engine focused on non-commercial content. Its API is accessible through api2.marginalia-search.com (current) and the legacy api.marginalia.nu / api.marginalia-search.com endpoints, and allows developers to perform web searches against the Marginalia index.

Marginalia Search publishes 2 API contracts indexed on the APIs.io network, including Filters API, and 1 more. Tagged areas include Open Source, Search, and Web Search.

The Marginalia Search catalog on APIs.io includes 1 Spectral governance ruleset.

Marginalia Search’s developer surface includes authentication and 8 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

24.8/100 emerging ▬ flat Agent 21/100 agent aware Front door AI 2/6 trace Heartbeat 100/100 alive Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

AccessFreemiumSelf serve⚡ Free to try

1 published contract

Open Source Search Web Search

Kin Score

Kin Score How this is scored →
scored 2026-11-13 · rubric v0.28.0

Composite quality — 24.8/100 · emerging

Contract Quality 9.3 / 19

Developer Ergonomics 3.2 / 15

Access Clarity 1.0 / 15

Operational Transparency 1.2 / 10

Contract Governance 1.2 / 9

Discoverability 4.3 / 8

Regulatory Posture 0.9 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 21/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 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

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

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.

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 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% 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):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship Ask about this →
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) Ask about this →
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes Ask about this →
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0 Ask about this →
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link Ask about this →
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document Ask about this →

9 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 6.4 — up to +18.7 composite points Ask about this →
Developer Ergonomics scores 21.4 — up to +15.7 composite points Ask about this →
Contract Quality scores 49.6 — up to +12.6 composite points Ask about this →

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.

Not sure how this applies to your stack? Ask about any one item. Kin Lane reads every question, looks at your profile and your situation, and replies with what a fix would take — scoped to that one area, priced up front, yours whether you ship it or not. Ask a question →

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/marginalia-search/apis.yml: open an issue on github.com/api-evangelist/marginalia-search 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 2

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

Marginalia Search Filters API

Manage named search filters (new API only).

Marginalia Search API

Search the Marginalia index.

Open Collections 3

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

Marginalia Search Filters API

OPEN COLLECTION

Marginalia Filters Search API

OPEN COLLECTION

Marginalia Search API

OPEN COLLECTION

Marginalia Search API pricing

Not yet checked against Marginalia Search's own pricing page. Compiled by API Evangelist on 2026-05-04; confirm before you rely on a figure. A free plan or tier is listed.

Plan	Price
Free freemium	Free
Professional paid	Free
Enterprise enterprise	—

Plan details, limits and sources →

Rate limits

Free Tier Default: 10 requests per minute
Free Tier Monthly Quota: 1000 requests per month
Professional Tier Default: 100 requests per minute

Compiled by API Evangelist, not yet checked against Marginalia Search's documentation. All 5 limits →

Pricing Plans 1

Published pricing tiers and plan structures.

Marginalia Search Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Marginalia Search Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Marginalia Search Finops

FINOPS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs. Counts are the severity each rule declares, not results of running them.

Marginalia Search API Rules

59 rules · 57 error-severity 1 warn-severity 1 info-severity

SPECTRAL

Security Posture 2

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

Marginalia Search Authentication

apiKey · 1 scheme

SECURITY

Marginalia Search Domain Security

TLSv1.3 · DNSSEC · DMARC

SECURITY

Agentic Access (API Evangelist recommendations) 1

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

Marginalia Search Agentic Access

5 operations · 2 acting

AGENTIC

Resources

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 2

Status, limits, changes, and where to get help

RateLimits

RateLimits

Contact

Contact

Commercial 2

Pricing, plans, and the legal terms of use

Plans

Plans

FinOps

FinOps

Company 1

The organization behind the API

Website

Website

Source (apis.yml)

aid: marginalia-search
name: Marginalia Search
description: Marginalia Search is an independent search engine focused on non-commercial content. Its API is accessible through
  api2.marginalia-search.com (current) and the legacy api.marginalia.nu / api.marginalia-search.com endpoints, and allows
  developers to perform web searches against the Marginalia index.
type: Index
deliveryModel:
  model: unknown
  open_source: false
  commercial: false
  callable_host: true
  label: Delivery model not determined — needs a product licence on record
  confidence: low
  source:
  - openapi
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  gated: none
  gated_source:
  - onboarding
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-11-13'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/marginalia-search.png
tags:
- Open Source
- Search
- Web Search
tags_raw:
- Open Source
- Search
- Web Search
- Open-Source
url: https://raw.githubusercontent.com/api-evangelist/marginalia-search/refs/heads/main/apis.yml
created: '2025-02-06'
modified: '2026-09-16'
specificationVersion: '0.23'
apis:
- aid: marginalia-search:marginalia-search-filters-api
  name: Marginalia Search Filters API
  description: Manage named search filters (new API only).
  humanURL: https://about.marginalia-search.com/article/api/
  baseURL: https://api2.marginalia-search.com
  tags:
  - Filters
  properties:
  - type: OpenAPI
    url: openapi/marginalia-search-filters-api-openapi.yml
  - type: Documentation
    url: https://about.marginalia-search.com/article/api/
- aid: marginalia-search:marginalia-search-search-api
  name: Marginalia Search API
  description: Search the Marginalia index.
  humanURL: https://about.marginalia-search.com/article/api/
  baseURL: https://api2.marginalia-search.com
  tags:
  - Search
  properties:
  - type: OpenAPI
    url: openapi/marginalia-search-search-api-openapi.yml
  - type: Documentation
    url: https://about.marginalia-search.com/article/api/
common:
- type: Plans
  url: plans/marginalia-search-plans-pricing.yml
- type: RateLimits
  url: rate-limits/marginalia-search-rate-limits.yml
- type: FinOps
  url: finops/marginalia-search-finops.yml
- type: AgenticAccess
  url: agentic-access/marginalia-search-agentic-access.yml
- type: DomainSecurity
  url: security/marginalia-search-domain-security.yml
- type: Authentication
  url: authentication/marginalia-search-authentication.yml
- type: Website
  url: https://marginalia-search.com/
- type: GitHubOrganization
  url: https://github.com/MarginaliaSearch
- type: Contact
  url: mailto:contact@marginalia-search.com
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Marginalia Search API — frequently asked questions

Does Marginalia Search have an API?

Yes. APIs.io lists 2 APIs from Marginalia Search, including Marginalia Search Filters API and Marginalia Search API.

Is there an OpenAPI specification for the Marginalia Search API?

Yes. APIs.io indexes 2 OpenAPI specifications for Marginalia Search, each linked for download from this page.

How do I authenticate with the Marginalia Search API?

Marginalia Search uses bearer-token authentication (apiKey · 1 scheme). The details are profiled on APIs.io as Marginalia Search Authentication.

How much does the Marginalia Search API cost?

APIs.io lists 3 pricing plans for Marginalia Search, with each plan's price, limits and inclusions under Pricing on this page.

Is the Marginalia Search API ready for AI agents?

Marginalia Search has a Kin Score of 24.8 out of 100 (emerging) and an Agent Readiness score of 20.7 (agent-aware), scored by API Evangelist on 2026-11-13.

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