Seltz

Seltz is a San Francisco-based AI infrastructure company building the web retrieval and knowledge layer for the agentic internet. Its Web Knowledge API gives LLMs, RAG pipelines, and autonomous agents real-time, context-engineered web data through a single call: POST /v1/search returns ranked, cleaned source documents, POST /v1/answer returns a direct RAG answer with citations, and an OpenAI-compatible /v1/chat/completions endpoint serves web-grounded chat. Rather than returning raw snippets like a traditional search API, Seltz shapes web content to maximize usefulness for machine reasoning. Founded in 2025 by Antonio Mallia (Amazon, Pinecone) and backed by Speedinvest and B Capital, Seltz ships official Python and TypeScript SDKs, a hosted MCP server, and integrations for OpenAI, Anthropic, Mistral, LlamaIndex, Agno, Langroid, Dify, n8n, and Zapier.

Seltz publishes 2 APIs on the APIs.io network: answer API and search API. Tagged areas include Company, Web Search, AI Infrastructure, Retrieval, and RAG.

Seltz’s developer surface includes documentation, API reference, getting-started guide, sandbox, pricing, signup flow, engineering blog, and 19 more developer resources.

🌐 Visit website 📡 Source on GitHub

42.5/100 developing ▬ flat Agent 33/100 agent ready saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

1 APIs 1 MCP Servers

Company Web Search AI Infrastructure Retrieval RAG Agents LLMKnowledge APIDeveloper Tools MCP

Kin Score

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

Composite quality — 42.5/100 · developing

Contract Quality 11.5 / 23

Developer Ergonomics 10.2 / 18

Access Clarity 7.8 / 18

Operational Transparency 2.2 / 12

Contract Governance 0.5 / 11

Discoverability 6.8 / 9

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 33/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 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

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.

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/seltz: 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 2

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

Seltz answer API

Answer operations

Seltz search API

Search operations

Open Collections 3

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

API Collection

OPEN COLLECTION

Seltz answer API

OPEN COLLECTION

Seltz answer search API

OPEN COLLECTION

MCP Servers 1

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

Seltz MCP Server

Official Seltz MCP server. Native integration for Claude Desktop, Cursor, VS Code, Windsurf, and other MCP-compatible AI tools. Remote HTTP/SSE server.

MCP SERVER

Security Posture 3

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

Seltz Authentication

apiKey · 2 schemes

SECURITY

Seltz Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Seltz Trust Center

trust center published

SECURITY

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

GettingStarted

Sandbox

SignUp

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

MCPServer

LLMsTxt

WellKnown

AgentSkill

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Conformance

Conformance

Lifecycle

Lifecycle

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Packages

Packages

SDKs

SDKs

Access & Security 3

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Compliance

Compliance

TrustCenter

TrustCenter

Operate 2

Status, limits, changes, and where to get help

Support

Support

ChangeLog

ChangeLog

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Overlay

Overlay

Source (apis.yml)

aid: seltz
name: Seltz
description: 'Seltz is a San Francisco-based AI infrastructure company building the web retrieval and knowledge layer for
  the agentic internet. Its Web Knowledge API gives LLMs, RAG pipelines, and autonomous agents real-time, context-engineered
  web data through a single call: POST /v1/search returns ranked, cleaned source documents, POST /v1/answer returns a direct
  RAG answer with citations, and an OpenAI-compatible /v1/chat/completions endpoint serves web-grounded chat. Rather than
  returning raw snippets like a traditional search API, Seltz shapes web content to maximize usefulness for machine reasoning.
  Founded in 2025 by Antonio Mallia (Amazon, Pinecone) and backed by Speedinvest and B Capital, Seltz ships official Python
  and TypeScript SDKs, a hosted MCP server, and integrations for OpenAI, Anthropic, Mistral, LlamaIndex, Agno, Langroid, Dify,
  n8n, and Zapier.'
url: https://raw.githubusercontent.com/api-evangelist/seltz/refs/heads/main/apis.yml
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  generated: '2026-09-03'
  method: derived
image: https://seltz.ai/favicon.ico
x-type: company
x-source: vc-portfolio
x-backed-by:
- speedinvest
- b-capital
x-tier: profiled
x-tier-reason: has-public-api
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-21'
tags:
- Company
- Web Search
- AI Infrastructure
- Retrieval
- RAG
- Agents
- LLM
- Knowledge API
- Developer Tools
- MCP
apis:
- aid: seltz:seltz-answer-api
  name: Seltz answer API
  description: Answer operations
  humanURL: https://docs.seltz.ai
  baseURL: https://api.seltz.ai
  tags:
  - Answers
  tags_raw:
  - answer
  properties:
  - type: OpenAPI
    url: openapi/seltz-answer-api-openapi.yml
  - type: Documentation
    url: https://docs.seltz.ai
  - type: APIReference
    url: https://docs.seltz.ai/api-reference/introduction
  - type: Authentication
    url: authentication/seltz-authentication.yml
  - type: ErrorCatalog
    url: errors/seltz-problem-types.yml
  - type: Conventions
    url: conventions/seltz-conventions.yml
  - type: DataModel
    url: data-model/seltz-data-model.yml
- aid: seltz:seltz-search-api
  name: Seltz search API
  description: Search operations
  humanURL: https://docs.seltz.ai
  baseURL: https://api.seltz.ai
  tags:
  - Search
  tags_raw:
  - search
  properties:
  - type: OpenAPI
    url: openapi/seltz-search-api-openapi.yml
  - type: Documentation
    url: https://docs.seltz.ai
  - type: APIReference
    url: https://docs.seltz.ai/api-reference/introduction
  - type: Authentication
    url: authentication/seltz-authentication.yml
  - type: ErrorCatalog
    url: errors/seltz-problem-types.yml
  - type: Conventions
    url: conventions/seltz-conventions.yml
  - type: DataModel
    url: data-model/seltz-data-model.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://www.seltz.ai/
- type: Overlay
  url: overlays/seltz-openapi-overlay.yaml
- type: DomainSecurity
  url: security/seltz-domain-security.yml
- type: DeveloperPortal
  url: https://console.seltz.ai
- type: Documentation
  url: https://docs.seltz.ai
- type: APIReference
  url: https://docs.seltz.ai/api-reference/introduction
- type: GettingStarted
  url: https://docs.seltz.ai/quickstart
- type: Sandbox
  url: https://console.seltz.ai/playground
- type: Pricing
  url: https://seltz.ai/pricing
- type: SignUp
  url: https://console.seltz.ai
- type: TermsOfService
  url: https://seltz.ai/terms
- type: PrivacyPolicy
  url: https://seltz.ai/privacy-policy
- type: Blog
  url: https://seltz.ai/blog
- type: Support
  url: https://seltz.ai/contact
- type: GitHubOrganization
  url: https://github.com/seltz-ai
- type: Packages
  url: packages/seltz-packages.yml
- type: SDKs
  url: packages/seltz-packages.yml
- type: MCPServer
  url: mcp/seltz-mcp.yml
- type: LLMsTxt
  url: llms/seltz-llms.txt
- type: WellKnown
  url: well-known/seltz-well-known.yml
- type: Conformance
  url: conformance/seltz-conformance.yml
- type: Compliance
  url: https://trust.seltz.ai/
- type: TrustCenter
  url: security/seltz-trust-center.yml
- type: Lifecycle
  url: lifecycle/seltz-lifecycle.yml
- type: ChangeLog
  url: changelog/seltz-changelog.yml
- type: AgentSkill
  url: skills/_index.yml
x-enrichment:
  date: '2026-07-21'
  status: enriched
  artifacts_added: 18
  pass: local-v1

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