Apidog makes the design the source of truth. We think the code is.
Apidog's design→mock→test→docs pipeline is the right shape. We build the same shape from the other end — and which end you start from decides whether drift is possible at all.
Apidog is the most coherent product in the API-client category and its skeleton is genuinely the right one: one artifact feeding documentation, mocks and tests, so they cannot disagree. It has been spec-first since day one rather than bolting a spec onto a request client. It is free for up to four users. This is not a weak competitor and we are not going to pretend the disagreement is about quality.
A design-first tool is only as accurate as the person keeping the design current. The router needs nobody.
Side by side
| Apidog | APIOS | |
|---|---|---|
| Source of truth | The API design, maintained by hand | The source tree, read on every push |
| Keeping it current | Someone updates the design when the code changes | Nobody — a push opens a proposal |
| Detects code that drifted from the design | No | That is the entire product |
| Review gate before publish | No | First-class, role-split, audited |
| Free tier | Four users | Five seats, three repositories |
| Self-hosting | No | Every tier, including free |
| Design-time editing | Excellent visual designer | None — we read code, we do not author specs |
| Breadth of client features | Very broad, mature | Narrower |
2 of these 8 rows go to Apidog. They are in the table rather than left out of it.
Design-first is right until someone is in a hurry
The model works exactly as advertised on the day the design is written. Then a service ships a hotfix at 6pm, the route changes, and the design does not. Nothing in a design-first tool notices, because the design is the input — there is no second opinion to disagree with it. Drift is not a discipline problem, it is a structural one: any artifact a human has to remember to update will eventually not be.
We are not a spec editor, deliberately
Hand-editing the OpenAPI document is the one feature we refuse to build, and it is the clearest difference between these two products. Adding it would reintroduce the second source of truth this exists to remove. If you want to design an API before writing it, Apidog does that well and we do not do it at all.
Who should stay with Apidog
If your team genuinely designs contracts before implementing them, reviews the design as the artifact, and has the discipline to keep it current, Apidog fits that workflow better than we do. The teams we are right for are the ones where the code moves first and the documentation is always catching up.
Don’t take our word for the drift
Connect a repository and we’ll count the endpoints that aren’t in your published reference. It’s a measurement, not a claim — and it’s free.
Verified 14 August 2026. Pricing and capabilities in this category move quarterly — if something here has gone stale, tell us and we’ll correct it.