aid: lapis name: LAPIS description: >- LAPIS (Lightweight API Specification for Intelligent Systems) is a compact, LLM-native API description format authored by Daniel Garcia (cr0hn). It is designed as the format you convert your OpenAPI specifications to when the consumer is a Large Language Model rather than a code generator or human reader. By replacing JSON/YAML structural overhead with a function-signature syntax, indentation-based sections, and centralized definitions for errors, webhooks, rate limits, and workflows, a typical LAPIS document carries the same semantic information as its OpenAPI source while consuming roughly 70-80 percent fewer tokens. LAPIS is not a runtime format and does not replace MCP, function calling, or OpenAPI itself - it is an intermediate representation optimized for AI agents that need to reason about an API inside a constrained context window. type: Index image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg tags: - API - Specification - LLM - AI Agents - OpenAPI - Token Optimization - Standards url: https://raw.githubusercontent.com/api-evangelist/lapis/refs/heads/main/apis.yml created: '2026-05-06' modified: '2026-05-06' specificationVersion: '0.19' apis: - aid: lapis:lapis-spec name: LAPIS Specification description: >- The LAPIS specification defines a token-minimal, LLM-native format for describing HTTP APIs. A LAPIS document is organized into up to seven indentation-based sections - [meta], [types], [ops], [webhooks], [errors], [limits], and [flows] - each carrying a focused slice of the API contract. The format draws its syntax from function signatures rather than nested data structures, uses scalar types (str, int, float, bool, date, datetime, file, any) with array, map, optional, and default modifiers, and centralizes cross-cutting concerns like errors and rate limits so they are described once and applied globally. The current release is version 0.1.0 (status Draft) released 2026-02-16 under the Creative Commons Attribution 4.0 license, and the specification is published in both English and Spanish. humanURL: https://github.com/cr0hn/LAPIS/blob/main/spec.en.md tags: - Specification - LLM - OpenAPI - Standards properties: - type: Documentation url: https://github.com/cr0hn/LAPIS/blob/main/spec.en.md title: LAPIS Specification (English) - type: Documentation url: https://github.com/cr0hn/LAPIS/blob/main/spec.es.md title: LAPIS Specification (Spanish) - type: APIReference url: https://github.com/cr0hn/LAPIS/blob/main/spec.en.md#16-formal-grammar-simplified-ebnf title: Formal EBNF Grammar - type: ChangeLog url: https://github.com/cr0hn/LAPIS/blob/main/CHANGELOG.md title: Changelog - type: GettingStarted url: https://github.com/cr0hn/LAPIS/blob/main/spec-example.en.md title: Walk-Through Example (English) - type: GettingStarted url: https://github.com/cr0hn/LAPIS/blob/main/spec-example.es.md title: Walk-Through Example (Spanish) - type: GitHubRepository url: https://github.com/cr0hn/LAPIS title: Canonical Specification Repository - type: Versioning url: https://github.com/cr0hn/LAPIS/releases title: Releases - type: Examples url: https://github.com/cr0hn/LAPIS/blob/main/examples/DigitalOcean-public.v2.lapis title: DigitalOcean Public API v2 (LAPIS) - type: Examples url: https://github.com/cr0hn/LAPIS/blob/main/examples/DigitalOcean-public.v2.yaml title: DigitalOcean Public API v2 (OpenAPI Source) common: - type: Portal url: https://cr0hn.github.io/LAPIS/ title: LAPIS Online Converter - type: Documentation url: https://github.com/cr0hn/LAPIS/blob/main/spec.en.md title: Specification (English) - type: Documentation url: https://github.com/cr0hn/LAPIS/blob/main/spec.es.md title: Specification (Spanish) - type: GettingStarted url: https://github.com/cr0hn/LAPIS#getting-started title: Getting Started - type: GitHubRepository url: https://github.com/cr0hn/LAPIS title: LAPIS Repository - type: ChangeLog url: https://github.com/cr0hn/LAPIS/blob/main/CHANGELOG.md title: Changelog - type: TermsOfService url: https://github.com/cr0hn/LAPIS/blob/main/LICENSE title: License (CC BY 4.0) - type: Compliance url: https://github.com/cr0hn/LAPIS/blob/main/CODE_OF_CONDUCT.md title: Code of Conduct - type: Security url: https://github.com/cr0hn/LAPIS/blob/main/SECURITY.md title: Security Policy - type: Contact url: https://github.com/cr0hn/LAPIS/blob/main/CONTRIBUTING.md title: Contributing Guide - type: CLI url: https://pypi.org/project/lapis-spec/ title: lapis CLI (lapis-spec on PyPI) - type: SDK url: https://pypi.org/project/lapis-spec/ title: lapis-spec Python Package - type: IDESupport url: https://github.com/cr0hn/LAPIS/tree/main/tools/ides/vscode title: LAPIS Visual Studio Code Extension - type: Sandbox url: https://cr0hn.github.io/LAPIS/ title: Browser-Based OpenAPI to LAPIS Converter - type: Issues url: https://github.com/cr0hn/LAPIS/issues title: Issue Tracker - type: Vocabulary url: vocabulary/lapis-vocabulary.yml title: LAPIS Normative Vocabulary - type: JSONSchema url: json-schema/lapis-document-schema.json title: LAPIS Document JSON Schema - type: JSONStructure url: json-structure/lapis-document-structure.json title: LAPIS Document JSON Structure - type: JSONLD url: json-ld/lapis-context.jsonld title: LAPIS JSON-LD Context - type: Examples url: examples/lapis-invoice-service-example.lapis title: Invoice Service LAPIS Example - type: Examples url: examples/lapis-meta-section-example.lapis title: Meta Section Example - type: Examples url: examples/lapis-types-section-example.lapis title: Types Section Example - type: Examples url: examples/lapis-ops-section-example.lapis title: Operations Section Example - type: Examples url: examples/lapis-webhooks-section-example.lapis title: Webhooks Section Example - type: Examples url: examples/lapis-errors-section-example.lapis title: Errors Section Example - type: Examples url: examples/lapis-limits-section-example.lapis title: Limits Section Example - type: Examples url: examples/lapis-flows-section-example.lapis title: Flows Section Example - type: Features data: - name: Function-Signature Syntax for APIs description: >- LAPIS uses operation headers shaped like function signatures (operation_name METHOD /path), input parameters prefixed with > and outputs prefixed with <, so an LLM reads each endpoint as a callable rather than as a deeply nested JSON object. - name: Seven-Section Document Model description: >- A LAPIS document is composed of up to seven sections in a fixed order - [meta], [types], [ops], [webhooks], [errors], [limits], and [flows] - with [meta] and [ops] required and the remainder optional based on what the API actually exposes. - name: Centralized Error Definitions description: >- Errors are declared once in [errors] using HTTP code plus a snake_case identifier, optionally bound to specific operations via @ops:name1,name2, eliminating the per-operation duplication of 400/401/404/429 responses that bloats OpenAPI documents. - name: First-Class Webhook Triggers description: >- The [webhooks] section captures both the payload shape and the trigger condition (lines prefixed with !) that fires the event, giving an LLM the why of an event rather than only the what that OpenAPI delivers. - name: Structured Rate Limits and Quotas description: >- The [limits] section expresses rate limits, quotas, body size caps, batch size caps, and tiered plan blocks as first-class declarative fields with scope annotations like @key, @global, @ip, @user, and @op:operation_name. - name: Multi-Step Workflow Flows description: >- The [flows] section describes how operations chain together using step1 -> step2 -> step3 notation, with branches (|), loops (*), waits (...(condition)), and inter-step data passing (op.field -> next_op(field)) so an agent learns canonical usage patterns alongside individual endpoints. - name: Field Versioning and Deprecation description: >- Field-level @since:X.Y annotations let an LLM determine whether a given field exists at the API version declared in [meta], and @deprecated optionally followed by a quoted note marks fields and operations that should not be used by new integrations. - name: Operation Modifiers description: >- Operations can carry +paginated, +deprecated, +idempotent, and +stream modifiers appended after the path, signaling pagination, retry safety, streaming response semantics, and deprecation status without verbose extension blocks. - name: Inline Object Types description: >- Types used by only a single operation can be inlined directly in the parameter list using {field: type, field: type} or [{field: type}] notation, avoiding pollution of [types] with single-use schemas. - name: 70-80 Percent Token Reduction description: >- For a representative mid-size API (11 operations, 8 types, 3 webhooks, 10 errors, limits, 4 flows), LAPIS measures roughly 1,500 tokens versus 6,500 for the equivalent OpenAPI YAML, a 0.23x ratio driven primarily by removing irrelevant metadata, repeated error definitions, and JSON/YAML key restatement. - name: Deterministic OpenAPI Conversion description: >- Section 14 of the spec defines field-by-field rules for converting OpenAPI 3.x into LAPIS, covering info, servers, securitySchemes, components.schemas, paths, webhooks, x-rateLimit and x-quota extensions, and links, making the conversion fully automatable. - name: Formal EBNF Grammar description: >- The specification ships a simplified EBNF grammar covering all seven sections, type expressions, modifiers, annotations, comments, and primitive lexical tokens, providing a normative reference for tool authors building parsers, linters, and highlighters. - name: Bilingual Specification description: >- The LAPIS specification is published in parallel English (spec.en.md) and Spanish (spec.es.md) editions, with matching walk-through examples (spec-example.en.md and spec-example.es.md) that narrate a sample Invoice Service API in both languages. - type: UseCases data: - name: Reducing LLM Context Cost description: >- Engineering teams whose AI features pass an OpenAPI specification into prompts on every call convert the spec to LAPIS once and pass the smaller LAPIS document instead, reducing per-call token spend by roughly 70-80 percent on the API description portion of the context window. - name: Powering AI Coding Assistants description: >- AI coding assistants that need to reason about a third-party API (generating client code, debugging a failing call, suggesting an endpoint) consume LAPIS as the API context layer, freeing more of the context window for the actual user prompt and conversation history. - name: Multi-Step API Agent Planning description: >- AI agents executing multi-step API workflows (create customer, create invoice, send invoice, await payment webhook) load a LAPIS document with a populated [flows] section so the planner has canonical workflow templates rather than having to infer chaining from individual operation descriptions. - name: Webhook-Aware Integrations description: >- Integration platforms that build webhook receivers use the [webhooks] section's trigger conditions (!) and headers (@header:X-Event-ID) to generate signature verification and event dispatch logic that knows when each event should fire and what identifying headers to expect. - name: Plan-Aware Rate Limit Enforcement description: >- Client SDKs and gateway integrations consume the [limits] section to configure backoff, request-throttling, and quota tracking per plan tier (free, pro, enterprise) and per scope (@key, @user, @op:name) without reading provider documentation in prose. - name: Specification Linting and Validation description: >- Tooling vendors and platform teams enforce LAPIS-conformant documents by validating against the EBNF grammar in spec section 16, catching missing required sections, invalid type expressions, and malformed annotations before the document is shipped to downstream consumers. - name: Cross-Provider API Comparison description: >- Because LAPIS strips presentation overhead and centralizes errors, limits, and flows, two LAPIS documents from different providers can be diffed and compared more directly than two OpenAPI specifications. - name: Onboarding Documentation for Internal APIs description: >- Platform teams generate LAPIS from internal OpenAPI sources to provide on-call engineers and product stakeholders a quickly readable, function-signature view of the company's services alongside the long-form OpenAPI documentation. - type: Integrations data: - name: OpenAPI 3.0 and 3.1 description: >- OpenAPI is the canonical source format for LAPIS. The lapis-spec Python tool ingests OpenAPI 3.0.x and 3.1.x in JSON or YAML, resolves $ref including circular references, flattens allOf/oneOf/anyOf, deduplicates inline versus named types, and emits a LAPIS document. - name: PyPI (lapis-spec) description: >- The reference command-line converter is published to PyPI as lapis-spec and exposes a lapis console script. Installation is pip install lapis-spec or uv pip install lapis-spec, and the CLI accepts -i/--input, -o/--output, and --no-validate flags. - name: Visual Studio Code description: >- The LAPIS Language extension (publisher lapis-spec, identifier lapis-lang) provides syntax highlighting for .lapis files, including section headers, scalar types, modifiers, IO markers, annotations, bracket matching, auto-closing pairs, and section folding. - name: Web Browser Converter description: >- A static JavaScript single-page application at https://cr0hn.github.io/LAPIS/ runs the OpenAPI to LAPIS conversion entirely in the browser via converter.js, highlighter.js, and app.js, supporting drag-and-drop, paste, copy, and download of .lapis files. - name: MCP and Function Calling description: >- LAPIS is positioned alongside (not as a replacement for) MCP and function calling. A LAPIS document is the context-layer description an LLM reads to understand an API; MCP servers and function-calling schemas remain the runtime invocation layer for actually executing operations. - name: Creative Commons Attribution 4.0 description: >- The specification text is licensed under CC BY 4.0, allowing adaptation, distribution, and commercial use provided attribution is given. The reference tooling (lapis-spec Python package) is MIT licensed, and the VS Code extension is CC BY 4.0. - name: GitHub Pages description: >- The browser-based converter is hosted on GitHub Pages from the cr0hn/LAPIS repository at https://cr0hn.github.io/LAPIS/, making it accessible without local installation or API keys. maintainers: - FN: Kin Lane email: kin@apievangelist.com