Firstbase

Firstbase is an all-in-one startup operating system that helps founders form, run, and grow a US business from anywhere in the world. Its products cover incorporation (Firstbase Start for LLCs and C-Corps in Delaware, Wyoming, New York, Texas and more), ongoing compliance and registered-agent services (Firstbase Agent), bookkeeping, invoicing and tax-ready financials (Firstbase Accounting), tax filing, and a virtual business address (Firstbase Mailroom). Firstbase markets an embedded "Incorporation API" for platforms that want to offer company formation to their own users, but publishes no public developer documentation, OpenAPI specification, or self-serve developer portal for it. Firstbase is a venture-backed company (a16z portfolio) added to the API Evangelist network and enriched from its public web surface.

Firstbase is profiled on the APIs.io network. Tagged areas include Company, Incorporation, Company Formation, Compliance, and Accounting.

Firstbase’s developer surface includes getting-started guide, support, engineering blog, pricing, signup flow, and 9 more developer resources.

🌐 Visit website 📡 Source on GitHub

21.2/100 emerging ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-07-27 · rubric v0.5

0 APIs

CompanyIncorporationCompany FormationComplianceAccountingBookkeepingTaxesRegistered AgentStartupsFintech

Kin Score

Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5

Composite quality — 21.2/100 · emerging

Contract Quality 0.0 / 25

Developer Ergonomics 3.5 / 20

Commercial Clarity 8.9 / 20

Operational Transparency 2.1 / 13

Governance 0.0 / 12

Discoverability 6.8 / 10

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 15

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 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

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/firstbase: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

Get Started 3

Portal, sign-up, and the first successful call

GettingStarted

GettingStarted

SignUp

SignUp

Login

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Lifecycle

Lifecycle

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

Support

Support

HelpCenter

HelpCenter

StatusPage

StatusPage

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

Source (apis.yml)

aid: firstbase
name: Firstbase
description: Firstbase is an all-in-one startup operating system that helps founders form, run, and grow a US business from
  anywhere in the world. Its products cover incorporation (Firstbase Start for LLCs and C-Corps in Delaware, Wyoming, New
  York, Texas and more), ongoing compliance and registered-agent services (Firstbase Agent), bookkeeping, invoicing and tax-ready
  financials (Firstbase Accounting), tax filing, and a virtual business address (Firstbase Mailroom). Firstbase markets an
  embedded "Incorporation API" for platforms that want to offer company formation to their own users, but publishes no public
  developer documentation, OpenAPI specification, or self-serve developer portal for it. Firstbase is a venture-backed company
  (a16z portfolio) added to the API Evangelist network and enriched from its public web surface.
url: https://raw.githubusercontent.com/api-evangelist/firstbase/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- a16z
x-tier: stub
x-tier-reason: portfolio-lead
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-19'
tags:
- Company
- Incorporation
- Company Formation
- Compliance
- Accounting
- Bookkeeping
- Taxes
- Registered Agent
- Startups
- Fintech
image: https://cdn.prod.website-files.com/609486d2fafa37698a57db5b/66fc614f8036f0625a063de1_Hero-new.png
apis: []
common:
- type: Website
  url: https://www.firstbase.io/
- type: GettingStarted
  url: https://www.firstbase.io/guide
- type: Support
  url: https://help.firstbase.io/hc
- type: HelpCenter
  url: https://help.firstbase.io/hc
- type: Blog
  url: https://www.firstbase.io/blog
- type: Pricing
  url: https://www.firstbase.io/pricing
- type: SignUp
  url: https://onboarding.firstbase.io/
- type: Login
  url: https://app.firstbase.io/
- type: TermsOfService
  url: https://www.firstbase.io/terms
- type: PrivacyPolicy
  url: https://www.firstbase.io/privacy-policy
- type: StatusPage
  url: https://status.firstbase.io/
- type: Lifecycle
  url: lifecycle/firstbase-lifecycle.yml
- type: DomainSecurity
  url: security/firstbase-domain-security.yml
- type: LLMsTxt
  url: llms/firstbase-llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence