---
title: "Automated API documentation without an OpenAPI spec"
description: "Most API doc platforms assume you already have an OpenAPI file. A researched map of what actually produces a reference doc when you don't: collection imports, AI write-ups, traffic discovery, and code-derived catalogs."
canonical: "https://getelva.ai/blog/automated-api-documentation-without-openapi-specs"
author: "Elva Team"
published: "2026-09-01"
lastModified: "2026-09-01"
tags: "API Documentation, OpenAPI"
---

# Automated API documentation without an OpenAPI spec

**TL;DR**

- Most API documentation platforms — ReadMe, Stoplight, Redocly, Bump.sh, Mintlify — assume an OpenAPI spec already exists; the real question for a team without one is what produces the *published reference doc* directly, not what produces the spec first.
- Four paths actually skip the spec: Postman generates docs straight from a saved collection, Theneo uses AI to write endpoint descriptions from a collection or schema, traffic-based discovery (folded into Postman since its July 2023 acquisition of Akita Software) infers an inventory from live requests, and code-derived catalogs render docs from source with no spec file anyone maintains.
- Each path still has a source of truth someone or something has to keep current — a hand-built collection, observed traffic, or the code itself — and that source, not the presence of a spec, is what determines whether the docs stay accurate.
- Elva publishes reference docs from the OpenAPI catalog it derives from a repo on every commit, so no one authors or re-imports anything to keep the published docs matching what the code does.

The phrase "automated API documentation" gets searched by two different people asking two different questions. One already has an OpenAPI spec and wants a nicer rendered page for it — that's what [most docs platforms](https://getelva.ai/blog/api-changelog-tools-compared.md) are built for. The other has no spec, isn't going to hand-write one this quarter, and wants to know what actually produces a reference doc anyway. This is for the second person, and the honest answer is that "no spec" doesn't mean "no source" — something still has to feed the docs, and which something determines whether they stay true.

## The default path assumes a spec exists

**[ReadMe](https://readme.com)**, **Stoplight**, **Redocly**, **[Bump.sh](https://bump.sh)**, and **Mintlify** are strong, mature products for rendering documentation, and every one of them is built around ingesting an OpenAPI document as the primary input. Redocly and Bump.sh both treat continuous sync against that spec as a first-class feature, so the moment the spec updates, the rendered docs follow. That's a real strength — and it just relocates the actual problem, which is that [most APIs in production have no spec, or one that's already drifted from the code](https://getelva.ai/blog/generate-openapi-spec-from-code.md). None of these five platforms manufacture the input they need; a team without a spec is a team not yet served by any of them.

## Four paths that skip the spec

**Collection-based generation.** Postman can publish a documentation page directly from a saved collection — its requests, folders, descriptions, and examples — with no OpenAPI file involved at any point. This genuinely removes the spec requirement, but it substitutes a different hand-maintained artifact: an endpoint nobody added a request for has no documentation, which is the same coverage gap [a manually maintained spec has](https://getelva.ai/blog/automatic-api-contracts-without-manual-specs.md), just moved one layer over. Pricing for Postman's platform, including its docs features, is on its [pricing page](https://www.postman.com/pricing/).

**AI-assisted write-ups from an existing artifact.** **[Theneo](https://www.theneo.io/api-reference)** accepts an OpenAPI spec, a Postman collection, or a GraphQL schema as its source and uses AI to write endpoint descriptions, generate multi-language code samples, and validate request and response examples, alongside a live "Try it" console and CLI-driven sync for keeping docs current in CI/CD. For a team with a collection but no spec, this is a meaningful shortcut: the collection stops being the thing customers read directly and becomes raw material for a properly written reference doc. The source artifact — whichever of the three it is — still needs to exist and stay current; the AI removes the writing burden, not the maintenance one.

**Traffic-based discovery.** The path closest to needing nothing authored beforehand is inferring the API's surface from requests it's actually receiving. Akita Software built exactly this using eBPF to discover endpoints from live traffic with no spec, collection, or code change required. Postman [acquired Akita in July 2023](https://blog.postman.com/postman-acquires-akita-for-automated-api-observability/) and folded its discovery and observability capabilities into its own platform rather than keeping it as a standalone product. What this approach produces reads more like an API inventory than a polished, publishable reference: it only knows about endpoints that received traffic during the observation window, which — as with any traffic-based tool — tends to miss admin routes, error paths, and anything used rarely.

**Code-derived catalogs.** The fourth path reads the implementation directly — routes, handlers, validators — and derives the equivalent of a spec as an internal, regenerated artifact rather than a file anyone maintains, then publishes the reference docs from that. This is [how Elva reads a repo](https://getelva.ai/blog/how-elva-reads-a-repo.md): it covers the full route table without depending on traffic having occurred, and because the catalog rebuilds on every commit, the published docs can't fall behind the way an unmaintained spec, an unmaintained collection, or an untouched traffic window all eventually do.

## What "automated" is actually buying

Every path above still has a source of truth. A collection needs someone to keep adding requests. A traffic-based inventory needs the traffic to have happened. AI writing on top of a collection or schema is only as complete as that collection or schema. The genuinely different property code-derived generation has is that its source — the code — updates on its own schedule as engineers ship features, and the docs pipeline just has to notice, rather than waiting for a person to remember to feed it something.

## A comparison table

| Tool | What it needs before it can publish docs | Who keeps the source current | One honest limitation |
| --- | --- | --- | --- |
| ReadMe / Stoplight / Redocly / Bump.sh / Mintlify | An OpenAPI spec | A person, or a generator feeding it one | Docs are only as current as the spec fed in |
| Postman | A saved or imported collection | A person maintaining the collection | No documentation for endpoints nobody added to the collection |
| Theneo | OpenAPI spec, Postman collection, or GraphQL schema | Whoever owns that source; AI writes the prose | Output quality tracks the completeness of the source artifact |
| Postman traffic discovery (ex-Akita) | Nothing authored — infers from live traffic | Production traffic itself | Covers only what received traffic during observation; inventory, not a polished reference |
| Elva | Nothing a human maintains — reads the repo | The code, rescanned every commit | Not a general docs platform for specs that live outside Elva's catalog |

## Where Elva fits

Elva's published reference docs come from the same OpenAPI catalog [derived from source on every commit](https://getelva.ai/blog/automatic-api-contracts-without-manual-specs.md), so the spec exists as machinery underneath the docs rather than as a file a person opens, edits, or re-imports. That closes the gap every other path in this comparison leaves open in a different place: Postman's docs are honest about the collection someone built; Theneo's write-up is honest about the source it was pointed at; traffic discovery is honest about the window it observed. Elva's docs are current with the code because they're generated from it directly, [the same pipeline that also derives contracts and blocks a breaking change from publishing](https://getelva.ai/blog/contracts-one-api-four-audiences.md).

## Choosing, in practice

- **Already have requests saved in Postman and want the fastest path to something public?** Its collection-based docs need nothing else, at the cost of only documenting what's in the collection.
- **Have a collection or schema but want AI to turn it into a properly written reference instead of a raw request list?** That's the specific gap Theneo is built to close.
- **No spec, no collection, but production traffic to learn from?** Traffic-based discovery, now part of Postman's platform, will build an inventory — plan to treat it as a starting point rather than the finished public doc.
- **Want the published docs to track the code with nobody assigned to keep a spec or collection updated?** That requires deriving the catalog from source directly, which is the specific problem [static analysis of the repo](https://getelva.ai/blog/generate-openapi-spec-from-code.md) solves.

The tools above are all legitimate answers to "how do I get documentation," and the honest differentiator between them isn't whether a spec is required — it's what has to keep happening, forever, for the result to stay true.

## FAQ

**Can I get API documentation without writing an OpenAPI spec?**

Yes, through several different paths. Postman generates a docs page directly from a saved collection with no OpenAPI file involved. Theneo accepts a Postman collection or GraphQL schema as an alternative to OpenAPI and uses AI to write the endpoint descriptions. Traffic-based discovery and code-derived catalogs skip authored input entirely, working from live requests or the source code instead.

**Does Postman require an OpenAPI spec to generate documentation?**

No. Postman renders a documentation page directly from a collection's saved requests, folders, and examples. The tradeoff is that the collection itself is a hand-maintained artifact — an endpoint nobody added to the collection has no documentation, the same gap a manually maintained OpenAPI file has.

**What does Theneo need to generate API documentation?**

An OpenAPI spec, a Postman collection, or a GraphQL schema as the source, from which it uses AI to write endpoint descriptions, multi-language code samples, and validated request and response examples, plus a live "Try it" console. It reduces how much of the write-up a person does by hand, but a source artifact — spec, collection, or schema — still has to exist and stay current.

**Can API docs be generated straight from production traffic, with no spec or collection?**

Historically, Akita Software did exactly this using eBPF-based traffic discovery to infer an API's live surface with nothing authored beforehand; Postman acquired Akita in July 2023 and folded that discovery capability into its own platform. The output is closer to an API inventory than a polished public reference, and it only covers endpoints that actually received traffic during observation.

**How does Elva produce documentation without a maintained spec?**

Elva reads routes, handlers, and types from a repository and derives an OpenAPI catalog on every commit, then renders the published reference docs from that catalog. Nobody opens or edits a spec file to keep the docs current — the docs regenerate because the code changed, not because someone remembered to re-export a collection or re-run an import.