Your internal APIs deserve the same care as your product.
Spec0 is the API platform built around how your teams actually work. Discover every API. Own them like products. Ship changes with confidence. GitOps-native, AI-augmented, and quietly opinionated about doing the right thing.
5 users · Unlimited APIs · No card required
✓ Spec parsed · OpenAPI 3.1
✓ Spectral lint · 87/100
✓ AI Spec Critic · 2 warnings, 1 suggestion
✓ Breaking-change scan · none
✓ Published orders-api v2.3.1 · 12 subscribers notified
Built for the way engineering teams already work
Stripe ships APIs developers love. So do you — internally.
Public APIs get the Stripe treatment: beautiful docs, versioned releases, considered changelogs. Internal APIs — the ones that actually run your business — get a Confluence page someone updated last year, a Slack thread, and a prayer.
The cost is invisible until it isn't. A breaking change nobody saw coming. A new hire who spends three weeks on an integration that should have taken three hours. A quarter spent rebuilding what someone else already shipped, because nobody knew it existed.
Spec0 closes the gap. The same care your public APIs get — discovery, versioning, mocks, changelogs, governance — applied to every API your teams build, with the GitOps workflow they already use for code.
One platform. Four things it gets right.
Subscriptions
Subscribe to an API. Stay subscribed to its changes.
A subscription isn't a permission grant. It's a relationship. When the API you depend on ships a breaking change, you hear about it before your code does. When its owners deprecate an endpoint, you get a heads-up and a migration path. When you need to reach the team behind it, there's a channel — not a guess.
Your integrations break less because the people behind them tell you what's changing.
- 2h ago
Orders API v2.3.0
Breaking: /v1/orders deprecated, migrate by Oct 1
- yesterday
Inventory API
New endpoint: POST /stock/reserve
- 3 days ago
Auth API
Changelog: improved error responses
Mock servers
Mocks belong with the API, not in a separate tool.
Spec0's mock server is a first-class part of every API. Spin one up from the API page, share its endpoint with frontend or partner teams, point your tests at it. Schema-correct responses generated from the spec — not hand-written examples that drift the moment the API changes.
Need to run mocks inside your own VPC or in CI? The same mock server is open source and self-hostable — same engine, same behaviour, same UI.
Operations
- GET /orders
- GET /orders/{id}
- POST /orders
- PATCH /orders/{id}
- DELETE /orders/{id}
Request
GET /orders/42
Accept: application/jsonResponse — schema-correct, generated from spec
{
"id": "42",
"status": "FULFILLED",
"totalCents": 8499,
"createdAt": "2026-05-12T09:14:00Z"
}spec-0/mock-server
Self-host the same mock engine — open source, MIT.
AI-native
Bring your own LLM. We bring the context.
Spec0 is AI-native in the way that actually matters: the AI knows your APIs. Connect your own LLM key (Anthropic, OpenAI, or hosted by us if you prefer) and the platform becomes a thinking partner.
-
AI Spec Quality Critic
LiveA senior-designer second pass on every spec, surfacing the issues mechanical linters can't see.
-
AI Changelog Generator
LiveDraft a customer-readable changelog from the diff and breaking-change summary, in your team's tone.
-
Monday Org Pulse
ComingYour platform's weekly read on what changed, what's risky, and what to look at first.
-
Model Context Protocol
LiveConnect Claude, Cursor, or any MCP-compatible client. Ask questions about your APIs in plain English, grounded in real specs.
Your provider, your bill, your model-side data residency. We store what the AI was used for — never what it said.
A platform two audiences agree on.
For developers
Spend less time hunting, more time shipping.
- Find any API in your org without DMing someone first.
- Mock servers that match the spec, every time.
- Subscribe once; get notified before things break.
- Ship from CI with one command, gated on quality you trust.
“It's the API catalog we kept saying we'd build ourselves, except it's done and it actually works.”
For engineering leaders
Visibility into the integration fabric of your org.
- Every API, every team, one screen.
- Governance posture you can show your auditor.
- AI-narrated weekly read on org health (where most platforms stop at dashboards).
- Standards enforced in CI, not in meetings.
“We stopped guessing about API quality the week we turned Spec0 on.”
GitOps
Your CI publishes the API. Spec0 enforces the policy.
Spec0 doesn't ask you to leave your existing workflow. The CLI runs in any CI runner, the spec lives in your repo, the policies are configured once in the platform and enforced on every publish. Code is the source of truth. The platform agrees.
Lint, review, version, publish — in one CI step.
name: Publish API
on:
push:
tags: ['v*']
jobs:
publish:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- name: Publish to Spec0
uses: spec-0/publish-action@v1
with:
spec: ./openapi.yaml
version: ${{ github.ref_name }}
fail-on-breaking: truePricing
Free to start. Talk to us when you're ready to grow.
Free
Everything you need to try Spec0 with your team.
- Up to 5 users
- Unlimited APIs and mocks
- Spec0 CLI + GitHub Actions
- Dashboards included
- Open-source mock server, self-host forever
Pro & Enterprise
For orgs that ship a lot — or have compliance to answer to.
AI features, governance, SSO, audit retention, BYO-LLM and on-prem options. We're still talking to design partners on pricing — so the honest answer is a conversation, not a calculator.
- AI Spec Critic, Changelog Generator, Subscriber Review
- AI-narrated weekly digests
- BYO-LLM (Anthropic, OpenAI, Bedrock, Azure)
- SSO/SAML, RBAC, audit retention, DPA
Internal APIs are the fabric of your engineering org.
The ones nobody pays attention to are the ones that take down your Tuesday. Spec0 makes the right thing the easy thing — discover, own, version, mock, subscribe, review. Then it gets quietly out of the way.