Nango by Nango

# Fix list: Nango

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/nango, the October 2026 research run, assessed 1 October 2026. Grade B, 67.9 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 Nango: 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. Payments & pricing, 40 out of 100, up to 7.5 more on the total

Why it scored 40: No x402, MPP or L402 (0). Per-unit prices published without a login, $0.29 per connection a month, $0.72 per compute hour and $0.50 per GB on Pay-as-you-go (20). Free plan with 10 connections, 10 compute hours and 10 GB a month and no card (20). A person signs up in a browser (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.

## 2. Security & auth, 67 out of 100, up to 5.8 more on the total

Why it scored 67: Environment secret keys can be scoped (agent sessions need `environment:agent_sessions:write`), end users connect through short-lived connect session tokens, and agent sessions get their own token, though we found no rotation guidance for secret keys (26). An agent session is limited to one tenant and the agent can't see raw credentials or widen its own scope, but there's no approval step for write actions (14). Agent sessions pass third-party API content straight to the agent and we found no prompt-injection guidance (5). Logs for 15 days on every plan, and an audit trail (added 3 September 2026) only on Enterprise (10). security.txt valid, SECURITY.md with private reporting, SOC 2 Type II in the trust centre, no formal bug bounty, and the two CVEs of September 2026 were published through NVD by VulnCheck, with nothing on Nango's own advisory page (12).

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.

## 3. Reliability, 78 out of 100, up to 4.4 more on the total

Why it scored 78: Better Stack page at status.nango.dev with history, though it tracks one component, Nango Cloud Health (20). Four degraded periods in the last 90 days and no outage, a third-party SSO problem on 16 July 2026 (2 hours 15 minutes), missing logs on 3 August (1 hour 26 minutes) and slow records database on 14 September (3 hours 35 minutes) and 23 September (20). Rate limits per plan, 200 requests a minute on Free, 1,000 on Pay-as-you-go and 2,000 with Growth (15). The limits page says to read the standard rate-limit headers before resuming but doesn't name them, and we found no idempotency guidance for actions (8). Enterprise lists dedicated SLAs with no published figure (5). Auth, proxy and agent sessions are sold as GA (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.

## 4. Agent ergonomics, 74 out of 100, up to 4.2 more on the total

Why it scored 74: An agent session serves only the tools for one tenant's tagged connections through its own MCP URL, with a proxy meta tool instead of hundreds of tool definitions (20). Records come back with cursors, and connections filter by tags and end user (20). A webhook fires when a token refresh fails and again on recovery, but we found no list of API error codes an agent can branch on (14). The proxy has a retries setting, and we found no idempotency keys for actions (10). Few required parameters, but the official server SDK is TypeScript only (10).

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.

## 5. Schema & documentation, 85 out of 100, up to 2.4 more on the total

Why it scored 85: OpenAPI file in the repository at docs/spec.yaml (25). llms.txt and Markdown docs (10). The docs say when to use the proxy, actions, syncs or an agent session, and agent sessions expose a `nango_proxy` meta tool to the agent (15). The OpenAPI file types the management endpoints, but the proxy passes provider requests through untyped by design (10). Examples throughout the guides, with error responses described per feature, not in one catalogue (10). A dated changelog with breaking changes called out, twelve entries in September 2026 alone (15).

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. Transparency & trust, 78 out of 100, up to 1.9 more on the total

Made of editorial 63, provenance 92.

Why it scored 78: Source on GitHub under the Elastic License 2.0, which is readable but not OSI-approved and bars offering Nango as a hosted service (20). The docs state AES-256-GCM under AWS KMS envelope keys, soft deletion at once and hard deletion after 31 days, 15-day log retention and a GDPR DPA by default (25). Breaking changes are announced in the changelog with migration guides (the nango.yaml sunset of 16 September 2026), but we found no deprecation policy with notice periods (8). The docs say tokens sit in PostgreSQL in AWS, but we didn't find a public subprocessor list outside the trust centre (10).

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):

- Domain age: nango.dev, registered 2022-05-31 (4 years) (7 of 15)

## 7. Maintenance & community, 90 out of 100, up to 0.9 more on the total

Why it scored 90: Changelog entries up to 22 September 2026 and v0.71.6 shipped after 10 August (30). v0.71.0 to v0.71.4 between 14 July and 10 August, and twelve dated changelog entries in September (20). Issue numbers have passed 7,000 with 31 open, the newest of them filed between 12 and 29 August 2026 (20). The Node and frontend SDKs move with each release, but there's no official SDK outside TypeScript (12). Monorepo with CI and current dependencies (8).

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.

## Deductions

Each comes off the total. A fixed and documented problem counts for less at the next check.

- 2026-09-04, CVE-2026-9317 (CVSS 9.2). The runner's tRPC server in Nango before 0.71.6 didn't enforce RUNNER_SECRET_KEY, so anyone who could reach the runner port could run arbitrary JavaScript. Fixed in 0.71.6. Recent and critical, though it needs network access to the runner (https://github.com/advisories/GHSA-9cph-w8mv-q56r)
- 2026-09-16, CVE-2026-92804 (high). Nango through 0.70.4 didn't validate caller-supplied connection configuration values. Fixed in later releases. Together with the runner flaw we deduct 5, less than the maximum because both are fixed and disclosed (https://github.com/advisories/GHSA-29mm-6vmq-g8cg)

## 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.

- Whether CVE-2026-9317 or CVE-2026-92804 affected Nango Cloud, or only self-hosted runners.
- Whether the nango.yaml sunset on 16 September 2026 was announced in advance.
- Which headers the API returns on a 429, since the limits page doesn't name them.
- We didn't find a subprocessor list outside the trust centre.
- The pricing page lists HIPAA, SAML SSO and SCIM under Enterprise while the changelog of 2 September 2026 puts SAML SSO and the HIPAA BAA under the Growth add-on.

## Weaknesses

- Audit trail only on Enterprise, and logs kept 15 days on every plan
- Two CVEs fixed in September 2026, one critical, neither on Nango's own advisory page
- Status page tracks a single component
- No prompt-injection guidance for content agent sessions pass through
- ELv2 bars offering Nango itself as a hosted service

## 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.

- Create one agent session per tenant from your backend and pass only the mcp_url and session_token to the agent
- Tag connections with your own user and organisation IDs so sessions can select them
- Listen for the refresh-failure webhook and send the user a reconnect link instead of retrying
- Read the rate-limit headers on a 429 and wait for the reset before resuming
- Run 0.71.6 or later when self-hosting, and keep the runner port off the network

## What the review panel asked for

- A keyless sandbox
- own advisory page entries
- Cloud impact statement

## 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.