Fillout

# Fix list: Fillout

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/fillout, the October 2026 research run, assessed 8 October 2026. Grade D, 52.2 out of 100.

This is everything the published grade says the listing lacks, the biggest possible gain to the total first. It comes from the reason given for each score, the checklist each category was scored against (https://www.anchorterminal.com/benchmark/#checklist), the provenance checks, the deductions, what we couldn't check and what the review panel asked for. A fix counts at the next check, once it's public.

For a coding agent working on Fillout: work through the items below in the product, its docs and its public pages. Each category gives the reason for its score, with the points each checklist item earned, and the checklist itself, so the gap is the items that earned less than their points. Change the product, not the wording, and keep a note of what you changed and where it's published.

## 1. Security & auth, 37 out of 100, up to 11 more on the total

Why it scored 37: One API key per organisation, revocable and regenerable, with no scopes. OAuth apps use an authorisation code flow with no scopes or expiry documented, and a token invalidation endpoint (15). No read-only key and no confirmation before a submission is deleted. Member permissions by workspace exist on Team and Enterprise plans and don't apply to the key (3). Submissions are written by the public and the docs give no injection guidance (0). Audit logs record API key and OAuth app changes, on Enterprise only, kept 30 days, with no per-call log (6). SOC 2 Type 2 and a bug bounty are stated on the security page, with a report address. No security.txt and no public advisories found (13).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-security):

- 0 to 30, the credential model. 30 for OAuth 2.1 with scopes, or scoped and revocable keys with rotation. 20 for plain revocable API keys. 10 for one all-powerful key. 10 off when a secret can travel in a URL query string as a documented option.
- 0 to 20, read-only or least-privilege modes, and confirmation or approval for destructive actions.
- 0 to 15, prompt-injection posture where the tool returns untrusted content (documented mitigations or guidance). A tool that returns no untrusted content gets 10.
- 0 to 15, audit logs or per-call visibility for the operator.
- 0 to 20, a security programme. security.txt or a disclosure policy, a bug bounty, SOC 2 or ISO 27001, advisories handled in public.

Models are read for retention, whether API data trains models (and whether that's off by default), zero-retention options and certifications. Frameworks for telemetry defaults, approval hooks, guardrails and sandboxing.

## 2. Payments & pricing, 30 out of 100, up to 8.8 more on the total

Why it scored 30: No x402, MPP or L402 (0). Plan prices are public with response quotas per plan, and nothing is priced per call (10). The free plan includes REST API access and 1,000 responses a month. The pricing page doesn't mention a card, and we didn't walk the signup (20). A person has to sign up in a browser and copy the key from Developer settings (0).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-payments):

The published rubric, also on the [x402 page](https://www.anchorterminal.com/x402/).

- 40, a machine payment protocol (x402, MPP or L402) on the tool's own endpoints. 10 to 30 when it covers only some endpoints or only goes through a third party, and the note says which.
- 20, per-call or per-unit pricing published without a login. 10 for public plan-only pricing, 0 for "contact sales" or prices behind a login.
- 20, a free tier or trial that doesn't need a card.
- 20, autonomous onboarding, meaning an agent can get access without a person signing up in a browser (keyless use, x402, a programmatic key API).

Payment platforms and agent wallets rarely charge for their own API over a machine protocol, so the first line has steps for them, and the highest one that applies counts. 40 when x402, MPP or L402 runs on all their own endpoints, 30 when it runs on part of their own API, 25 when their merchants can accept one, 20 for running a facilitator, 15 for paying as a buyer, and 0 when the only protocol is their own. Merchant acceptance sits above a facilitator because the platform's own customers can charge agents through it, while a facilitator settles for sellers who wire up the protocol themselves. The counter-argument (a facilitator does more for the protocol as a whole) has a point. Each note says which step applied.

Open-source software you run yourself is scored on its hosted or paid option if it has one. A free, self-hosted package with nothing to buy gets 20, 20 and 20 for the last three lines, and 0 to 40 for the first only if it ships a payment protocol.

## 3. Agent ergonomics, 47 out of 100, up to 8.6 more on the total

Why it scored 47: Eight operations, so the surface is small. Submissions can be capped at 1 to 150 a page, with no field selection (12). `limit`, `offset`, date range, status, sort and text search, with `totalResponses` and `pageCount` in the reply (18). Errors are undocumented. Live errors are JSON with `statusCode`, `error` and a specific `message`, and a missing key answered 400 where 401 is usual (6). No idempotency key on created submissions. Deleting by ID is safe to repeat (3). Few required parameters, and one official SDK in TypeScript only (8).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-ergonomics):

- 0 to 25, context cost. For MCP, the number and size of the tool definitions (25 for ten or fewer compact tools, 15 for 11 to 30, 5 for more than 30, plus up to 10 back for toolsets, dynamic loading or read-only subsets). For APIs, whether responses can be sized (field selection, limits, summaries).
- 20, pagination, filtering and output-size controls.
- 20, actionable, documented error responses, codes and messages an agent can recover from.
- 20, idempotency or safe retries, and for MCP the `readOnlyHint` and `destructiveHint` annotations.
- 15, sensible defaults, few required parameters, and official SDKs in at least two languages.

Models are read for tool use, structured output, prompt caching, context length, batch and SDKs. Frameworks for how much code and how many defaults a tool-calling agent with MCP needs.

## 4. Reliability, 70 out of 100, up to 6 more on the total

Why it scored 70: Graded on the hosted lines for the REST API. Statuspage site at fillout.statuspage.io with seven components, one of them Developer API (20). Eight incidents between 10 July and 8 October 2026, none naming the Developer API. One was labelled major (29 August, 18 minutes, editor and dashboard), and the longest was 8 hours 50 minutes of slow custom domains on Zite Apps on 22 July (20). 5 requests a second per key (15). The docs say nothing about 429s or retries, and writes have no idempotency key, but live responses carry `ratelimit-limit`, `ratelimit-remaining` and `ratelimit-reset` headers (5). Enterprise lists custom agreements and SLAs, with no published SLA (0). The API is v1 with no beta label (10).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-reliability):

Hosted APIs, MCP servers, models and platforms.

- 20, a public status page with component history (Statuspage, Instatus, BetterStack or the vendor's own).
- 0 to 30, the incident record for the last 90 days on that page. 30 for a clean record or trivial incidents only, 20 for minor incidents only, 10 for one major outage (an hour or more of a core API down, or errors across the board), 0 for several. 5 when there's no history we could read, and the note says so.
- 15, rate limits documented with numbers.
- 15, documented 429 or overload handling (Retry-After, backoff guidance), and idempotency keys or safe-retry guidance where writes are involved.
- 10, an SLA published for any paid tier.
- 10, the surface agents use is generally available, not beta or preview.

Local packages, SDKs, frameworks and stdio MCP servers.

- 20, installs from an official package with supported runtimes stated.
- 25, a public CI and test suite, passing on the default branch.
- 0 to 25, open crash or regression issues relative to activity (25 for few and handled, 0 for many, old and unanswered).
- 15, semver discipline and breaking changes called out in a changelog.
- 15, version 1.0 or later, or declared stable.

Protocols are read from their reference implementations, the public facilitators or servers, spec stability and test vectors.

## 5. Schema & documentation, 63 out of 100, up to 6 more on the total

Why it scored 63: Public OpenAPI 3.0.1 spec with 8 operations and 31 schemas (25). llms.txt and a Markdown copy of each help page (10). Every operation and parameter has a one-line description, with no guidance on when to use which (6). Enums for status, sort and 38 question types, bounds on `limit` and a 10-item cap on created submissions, while answer values are untyped (11). The spec has no examples and documents only 200 responses (3). The path carries /v1, and the changelog is a product log by month with no API section. The last API item we found in it is from 2025 (8).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-schema):

APIs and MCP servers.

- 25, a machine-readable contract (a public OpenAPI file or similar; for MCP, typed JSON Schema inputs on every tool).
- 10, llms.txt or Markdown docs served for agents.
- 0 to 20, descriptions that say what a tool is for, when to use it and when not to, read from the tool definitions in the source or the API reference.
- 0 to 15, typed inputs with enums, constraints and required fields, and no free-form JSON blobs.
- 0 to 15, examples and documented error responses.
- 15, versioning and a public changelog.

Models are read from the API reference, the OpenAPI file, llms.txt, the structured-output and tool-use docs and the model cards. Frameworks from docs a model can follow, typed interfaces, examples and the API reference.

## 6. Maintenance & community, 46 out of 100, up to 4.7 more on the total

Why it scored 46: The changelog's newest entry is labelled October 2026, and the newest tagged Forms is August 2026, inside 90 days (20). Nine entries from August to October 2026, one of them tagged Forms, so half credit for the forms product (10). Support by email and live chat, described as 24/5 on the pricing page, with no public forum or issue tracker for the API (8). The one official SDK, `@fillout/api` 1.5.0, was last published on 5 May 2025 (5). Its repository has a release workflow and no tests that we saw (3).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-maintenance):

- 0 to 30, time since the last release, or the last published model or API change for a closed service. 30 within 30 days, 20 within 90, 10 within 180, 0 older.
- 20, at least three releases or dated changelog entries in the last 90 days.
- 0 to 25, responsiveness. Issues and pull requests answered on GitHub (the open issues and how recent the replies are). For closed services, a public changelog and a support or community channel that answers, 0 to 15.
- 15, presence in the official MCP registry under a verified namespace (MCP servers), or current official SDKs (APIs and models).
- 10, package health, current dependencies and CI.

Models are read for deprecation notice periods and model churn rather than release counts.

## 7. Transparency & trust, 69 out of 100, up to 2.7 more on the total

Made of editorial 53, provenance 85.

Why it scored 69: Closed service with public terms dated 2 July 2022, and an MIT client (15). Privacy policy of 7 October 2025, a GDPR page, EU hosting on Team and above and documented deletion routes. Retention is stated only as long as necessary, no public DPA was found, and the terms and privacy policy give different addresses (18). No deprecation policy found, and the terms allow changes with or without notice (0). Subprocessors are listed with countries and whether each may process submission data (20).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-transparency):

- 0 to 30, source availability and licence clarity. 30 for open source under an OSI licence, 15 for closed with clear terms, 0 for unclear terms.
- 0 to 30, data handling and retention statements that agree with each other (privacy policy, DPA, retention periods, subprocessors).
- 0 to 20, a deprecation policy or notices with dates.
- 0 to 20, telemetry disclosed with an opt-out (local software), or subprocessors and data locations disclosed (hosted).

The other half of Transparency and trust is the provenance score, computed from checked facts (below). The category score is the mean of the two.

Provenance checks not met in full (half of this category, computed from checked facts):

- Terms of service: read, states 6 of the 7 things a reader expects, and has 2 clauses that cost points (5.1 of 10)
- security.txt: not found (0 of 10)

## What we couldn't check

What we couldn't read counted as absent. Publishing it on a page a plain HTTP fetch can read (not only in a browser) lets the next check count it.

- unchecked: whether signing up for the free plan needs a card. The pricing page doesn't say and we didn't create an account.
- unchecked: how the API answers a real 429, and whether it sends Retry-After. We saw only the rate-limit headers on a 400.
- unchecked: webhook signing, retries and delivery timeouts. Nothing in the reviewed docs covers them.
- unchecked: OAuth token lifetime and scopes. The OAuth page documents neither.
- unchecked: the day of the latest changelog entry. Entries are labelled by month, so `lastRelease` is left empty.
- unchecked: the bug bounty's scope and platform. The security page states one exists and links to no programme page.
- unchecked: GitHub stars for fillout/api-client.
- The official MCP registry has no Fillout or Zite entry under a vendor namespace. A search for fillout returned one third-party server, io.usefulapi/fillout.

## Weaknesses

- No operation creates or edits a form. Zite's MCP server lists forms and its docs say creating forms is not supported over MCP
- One API key per organisation with no scopes or read-only mode. Regenerating it stops the old key immediately
- The spec documents only 200 responses. A request with no key returned 400, not 401, when we tried it
- No idempotency key on `POST /forms/{formId}/submissions`, and no webhook signing or retry policy in the reviewed docs
- The only official SDK is TypeScript, `@fillout/api` 1.5.0, last published on 5 May 2025

## What costs an agent a turn today

The notes we give agents before they call it. Each one is a workaround an agent shouldn't need.

- Build the form in the Fillout editor first. The API reads forms and writes submissions but can't create a form or change its questions
- Read the base URL from the Developer settings page. EU-hosted accounts use https://eu-api.fillout.com/v1/api
- Stay under 5 requests a second per key and read the `ratelimit-remaining` and `ratelimit-reset` response headers
- Page submissions with `limit` (at most 150) and `offset`, and stop at `pageCount`. `status=in_progress` returns unfinished ones
- Send at most 10 submissions per create call and don't retry blindly, because the call has no idempotency key

## When it's done

Send what changed and where it's published as a dispute (https://www.anchorterminal.com/builders/#disputes, or `POST https://www.anchorterminal.com/api/v1/contact` with `"kind": "dispute"`). Disputes are answered in public, and the listing is checked again by the same checklist. Paying for an audit or a listing claim changes nothing here.