> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ledgersyncappv2.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Reauthorize a connection

> Mint a hosted page the end-user opens to repair credentials or
re-consent at the institution, typically when the connection
reports `status = requires_action`.

**This endpoint is not gated on status.** It accepts an `active`
connection, but Finicity Connect Fix may report that there is
nothing to repair. Calling it on a healthy connection does not
guarantee that an account picker will open.

### Adding Finicity accounts

Use `POST /v3/clients/{client_id}/connections` with the existing
Client and the bank's v3 catalog `institution_id`. When routed to
Finicity, that opens Full Connect on the existing provider customer.
Have the end-user choose the option to add accounts under the
existing bank, then complete authorization and account selection.
The same institution login reuses the existing LedgerSync
connection. Starting Full Connect does not force a new connection
on every session; a different provider login can create one.
See that endpoint for detecting newly added accounts.

A Finicity `POST /connections/{connection_id}/refresh` updates
accounts already held by LedgerSync. It does not open account
selection or import an account that the user has not shared.

### What you get back

A hosted `reauth_url`, a LedgerSync-hosted page the end-user opens
to complete the source-specific flow (Finicity Connect Fix, MX
member reconnect, FDE credential recapture) against the existing
connection. Redirect the user to it; connection status changes
produce `connection.active` / `connection.failed` webhooks.
An already active connection may have no new status transition,
so do not require another `connection.active` event to finish a
no-op session.

The response also carries `source`: the provider the URL leads to.
See "Ids are not always stable" below.

### The URL is a reusable bearer credential

The link is **not** single-use. It stays valid until
`action.expires_at` (currently about six days out) and anyone
holding it can open the end-user's bank-linking session. Deliver it
over a channel you would use for a password reset, do not log it,
and do not embed it in a page that a third party can scrape.

### Ids are not always stable

Repairs aim to retain existing `con_` / `acc_` / `txn_` ids.
Finicity can issue a different underlying login during repair;
when that cannot be matched back to the existing connection, a
separate connection can result even if the response `source`
is unchanged. Re-list the Client's connections and accounts after
the session instead of treating a matching `source` as proof of
stable ids.

For a bank LedgerSync now serves exclusively through a different
provider, the URL we hand back is an add-bank link for that
provider rather than a repair link for the connection you named.
Today that is Finicity connections at such banks being redirected
to MX, and American Express is on that list in production. The
list is configuration and can change without an API version bump,
so branch on the response rather than on a bank you hard-coded.

When the redirect happens, the end-user's session creates a **new**
connection with a new `con_` id and new `acc_` / `txn_` ids, and
the connection you passed is left as it was.

Detect it from the response: `source` differs from the source
segment of the `connection_id` you sent. On that branch the
`connection.active` webhook that follows carries the **new**
connection's id, not the one you passed, so key off the Client
rather than the connection: wait for `connection.active`, then
re-list `GET /v3/clients/{client_id}/connections` and
`GET /v3/accounts?client_id=...` and re-map, rather than expecting
the old ids to come back.

### Call it because a person asked, not on a timer

Each completed session can share accounts you were not syncing
before, and newly shared accounts pull their statement history,
which is billable. Trigger this from an explicit user action. Do
not schedule it, do not retry it in a loop, and do not mint a
second link while the first is still valid.

Available for `FINICITY`, `MX`, and `FDE`. Uploaded-statement
(`PDF`) data is read-only and has no connection to reauthorize
(`400`). On `MX` and `FDE` you do not need this endpoint to pick up
a newly opened account: a plain refresh discovers it. See
`POST /connections/{connection_id}/refresh`.

Ownership is enforced server-side: a `connection_id` that
doesn't belong to the authenticated customer returns `404`.

### Empty-body POST

This endpoint takes no request body. Send an explicit
`Content-Length: 0` header so the upstream HTTPS load balancer
doesn't reject the request with `411 Length Required`.




## OpenAPI

````yaml /openapi.yaml post /connections/{connection_id}/reauthorize
openapi: 3.1.0
info:
  title: LedgerSync API
  version: '2026-05-22'
  summary: A modern REST API for connecting bank accounts and pulling financial data
  description: >
    > **First time here?** The [**Getting started**
    guide](https://portal.ledgersyncappv2.com/dashboard/getting-started) walks
    the full integration end-to-end (about 15 minutes). This page is the
    endpoint reference for after you've read it.


    Welcome. This is LedgerSync's API for connecting your users' bank

    accounts and pulling their transactions, statements, and account

    details.


    Everything is JSON over HTTPS. Errors are easy to read. Webhooks

    fire as state changes. Sandbox is one key away.


    ## Connection lifecycle and the two `connection.id` formats


    A Connection's `id` changes shape once the user finishes linking

    their bank — there are two distinct identifiers, and you must

    only use the canonical one to read accounts, transactions, or

    statements.


    1. **Placeholder id (pending state).** `POST /v3/clients/{id}/connections`
       returns `202 Accepted`. The initiate operation first surfaces
       a `connection_with_action` result whose embedded
       `connection.id` is a UUID-prefixed placeholder of the form
       `con_<uuid>` (e.g. `con_a1b2c3d4-e5f6-47a8-9b12-c3d4e5f6a7b8`), paired
       with a `widget_url`. The placeholder is **not** a valid id for
       any other endpoint — calling
       `GET /v3/connections/{placeholder_uuid}` returns
       `400 Bad Request` with `missing source separator`. Treat it as
       opaque routing state for the widget step only.
    2. **Canonical id (active state).** Once the user finishes the
       widget and the source pushes its first callback, the
       connection moves to `status=active` and the
       `connection.active` webhook fires. Exactly two surfaces report
       the canonical id `con_<SOURCE>_<bankAccountId>` (for example
       `con_FINICITY_41294`, `con_MX_1224`): the `connection.active`
       webhook payload, and `GET /v3/clients/{id}/connections`.
       **This** is the id every other endpoint accepts
       (`/accounts`, `/transactions`, `/statements`, refresh, delete).

    **Tell the two apart by shape, not by where you got them.** The

    initiate operation's `result` is a snapshot written once, at the

    moment the widget URL is issued, and nothing rewrites it

    afterwards. The operation is already `succeeded` while the user

    still has the widget open, so `status=succeeded` does **not** mean

    the bank is linked, and re-polling later returns exactly what it

    returned the first time. For Finicity and MX that is a

    placeholder. (An FDE initiate can return the canonical id

    directly; checking the shape covers both without special-casing

    the source.)


    The correct integration pattern is therefore:


    - Initiate the connection, capture `operation_id`.

    - Open `result.connection.action.widget_url` for the user. Store
      `result.connection.id` only if it matches
      `con_<SOURCE>_<bankAccountId>`; never store a `con_<uuid>`.
    - Wait for the `connection.active` webhook and read
      `data.connection.id` from it. If you cannot run a webhook
      handler, poll `GET /v3/clients/{id}/connections` and take the
      canonical id from there.

    Do not try to `GET /v3/connections/{placeholder_uuid}` during the

    pending window. Listing endpoints

    (`GET /v3/clients/{id}/connections`, `GET /v3/connections/{id}`)

    only ever return canonical ids, because they only surface

    connections that have reached `active`.


    ## Quick start


    Mint a sandbox key in the developer portal, then create your first

    **Client** (your end-user — the person whose bank we'll be reading):


    ```bash

    curl \
      https://api-sandbox.ledgersyncappv2.com/v3/clients \
      -H "Authorization: Bearer sk_test_..." \
      -H "Content-Type: application/json" \
      -d '{"email":"alice@example.com","name":"Alice"}'
    ```


    You'll get back a `Client` object with an `id`. From there the

    full flow is:


    1. **Register a webhook** at `POST /v3/webhooks/subscriptions` so
       you can be notified when the connection progresses.
    2. **Initiate a connection** at
       `POST /v3/clients/{id}/connections` with an `institution_id`
       from `GET /v3/institutions`. LedgerSync's router picks the
       underlying source. Every source hands back a `widget_url` in
       the `connection.requires_action` result — for FDE it points at
       a LedgerSync-hosted connect page where credentials are entered,
       never sent to the API.
    3. **Open the widget URL** in your user's browser. They pick
       their bank, log in, and choose accounts to share.
    4. **Receive `connection.active`** on your webhook URL. List
       accounts and transactions.

    **Don't want to build your own bank picker?** Skip steps 2–3: call

    `POST /v3/clients/{id}/connect-session` to get a LedgerSync-hosted

    link, and email it to your member. They open it, search for their

    own bank, pick it, and connect it — all on a page we host, with no

    `institution_id` needed up front. You still receive

    `connection.active` on your webhook exactly as above. Revoke a link

    at any time with `DELETE /v3/clients/{id}/connect-session/{sid}`.

    (This is the v3 replacement for the old `account/add/lite` widget.)


    Want a step-by-step walkthrough with curl per step plus a sandbox

    shortcut that skips the widget? Read the

    [Getting started
    guide](https://portal.ledgersyncappv2.com/dashboard/getting-started).


    ## Authentication


    Pass your secret key in the `Authorization` header as a Bearer

    token: `Authorization: Bearer sk_test_...` (sandbox) or

    `Bearer sk_live_...` (production). Treat secret keys like

    passwords — never embed them in mobile apps or front-end code.


    ## Conventions


    **Sync vs async.** Most endpoints respond synchronously — you

    get the resource back right away. A handful of flows are

    genuinely async (initiating a bank connection, extracting a

    statement, generating a verification report); those return

    `202 Accepted`

    with an `operation_id` you can poll, and the matching webhook

    fires when the work finishes.


    **Errors.** Every error is `{ "error": { "code", "message", "doc_url",
    "type" } }`.

    Branch on `code`. Click `doc_url` for the troubleshooting page.

    Every response carries an `X-LS-Trace-Id` header — paste it in

    support tickets and we can jump straight to your request.


    **Webhooks.** Every delivery carries `X-LS-Webhook-Signature`:

    hex HMAC-SHA256 over `X-LS-Webhook-Timestamp`, a literal `.`, and

    the **raw request body**, in that order. Signing the body alone

    will not match. Verify before trusting the payload. Full event

    catalog + signature example on the [Webhooks tab](#webhooks).


    ## Need help?


    Email [support@ledgersync.com](mailto:support@ledgersync.com) or

    open a thread in the developer portal. Quote the `X-LS-Trace-Id`

    from your response — it makes everything faster.
  contact:
    name: LedgerSync Developer Support
    email: support@ledgersync.com
    url: https://portal.ledgersyncappv2.com
  license:
    name: Proprietary
    url: https://ledgersync.com/terms
servers:
  - url: https://api-sandbox.ledgersyncappv2.com/v3
    description: >-
      Sandbox — use `sk_test_...` keys from the developer portal. Routes to the
      real Finicity and MX sandbox banks (FinBank, mxbank) via the same
      connector code paths as production.
  - url: https://api.ledgersyncappv2.com/v3
    description: >-
      Production — use `sk_live_...` keys. Hits real banks via Finicity, MX, or
      FDE depending on the connection.
security:
  - bearer: []
tags:
  - name: Clients
    description: |
      A **Client** is the end-user whose bank accounts you're managing
      — usually a real person or business. You create one Client per
      user before linking any accounts. Pass your own
      `external_id` to join Clients back to records in your system.
  - name: Connections
    description: |
      A **Connection** links a Client to a bank or financial-data
      source (Finicity, MX, or FDE). One Client can have many
      Connections — one per bank they've linked. You initiate a
      Connection, the user finishes it (widget or MFA), and a
      `connection.active` webhook tells you when it's ready.
  - name: Accounts
    description: |
      Once a Connection goes active, the bank's accounts (checking,
      savings, credit, loans) show up here. Use these endpoints to
      list, inspect, and refresh them.
  - name: Transactions
    description: |
      Posted transactions and pending charges for an account. New
      transactions are surfaced by a future push-delivery event for
      transactions after each refresh; you can also list/page them
      directly.
  - name: Statements
    description: |
      Period statements (usually monthly PDFs) the bank publishes.
      For FDE-sourced statements, extracted line items are attached
      after OCR completes.
  - name: Checks
    description: |
      Images of paper checks, captured alongside FDE statement
      extraction. FDE-only: Finicity and MX report `check_images`
      as `unsupported`. Fronts only — LedgerSync does not capture
      the back of a check, so there is no `side` field.
  - name: Operations
    description: |
      The handful of LedgerSync calls that genuinely run asynchronously
      return an `operation_id`. Poll it here, or just listen for the
      matching webhook — your call.
  - name: Webhooks
    description: |
      Manage where LedgerSync delivers event notifications. Each
      subscription has its own HMAC signing secret. Rotate it whenever
      you want — the old secret stays valid for 24 hours so deploys
      don't break verification.
  - name: ApiKeys
    description: |
      Create, list, and revoke API keys. Keys are scoped to one
      environment (sandbox or live). The plaintext secret is returned
      exactly once at creation — store it somewhere safe.
  - name: Institutions
    description: |
      The unified v3 institution catalog. Search by name; pick a row;
      pass its `id` to `POST /clients/{client_id}/connections`.
      LedgerSync's router decides which underlying source (Finicity,
      MX) to use — integrators don't pick a source.
  - name: Settings
    description: |
      Account-level settings the integrator manages once per environment.
      Currently exposes the redirect-URL allowlist consulted at
      `/connections/initiate`. Same scope as Stripe Connect / Plaid Link /
      OAuth — register your app's redirect URIs once, not per end-user.
  - name: Sandbox
    description: |
      Sandbox-only helpers. Use `GET /sandbox/institutions` to list
      the sandbox-eligible test banks you can target when creating a
      sandbox connection (Finicity FinBank, MX `mxbank`, FDE test
      extractors). Lifecycle transitions and webhooks come from the
      same real connector paths as live traffic — no synthetic
      lifecycle driver, no replay fixtures. Drive the widget with
      the public test bank credentials documented in the developer
      portal.
  - name: Metrics
    description: |
      Read-only aggregations powering the developer portal's "Metrics"
      page. Every endpoint is scoped to the authenticated principal's
      customer and environment — `sandbox` and `live` data never mix
      across the wire. Default window when `from`/`to` are omitted is
      the last 30 days (max 366).
  - name: Health
    description: A simple liveness probe. No auth required.
  - name: PortalGating
    description: |
      Developer-portal access-request endpoints (sandbox + live gating).
      These are HMAC-signed calls from the LedgerSync portal to v3 and not
      part of the integrator-facing API surface. Documented here so the
      single spec stays authoritative.
paths:
  /connections/{connection_id}/reauthorize:
    parameters:
      - in: path
        name: connection_id
        required: true
        description: |
          Canonical Connection id (`con_<SOURCE>_<bankAccountId>`) of the
          connection to repair. The placeholder UUID from initiate and
          any `con_PDF_*` id are rejected with `400`.
        schema:
          type: string
          example: con_FINICITY_41294
    post:
      tags:
        - Connections
      summary: Reauthorize a connection
      description: |
        Mint a hosted page the end-user opens to repair credentials or
        re-consent at the institution, typically when the connection
        reports `status = requires_action`.

        **This endpoint is not gated on status.** It accepts an `active`
        connection, but Finicity Connect Fix may report that there is
        nothing to repair. Calling it on a healthy connection does not
        guarantee that an account picker will open.

        ### Adding Finicity accounts

        Use `POST /v3/clients/{client_id}/connections` with the existing
        Client and the bank's v3 catalog `institution_id`. When routed to
        Finicity, that opens Full Connect on the existing provider customer.
        Have the end-user choose the option to add accounts under the
        existing bank, then complete authorization and account selection.
        The same institution login reuses the existing LedgerSync
        connection. Starting Full Connect does not force a new connection
        on every session; a different provider login can create one.
        See that endpoint for detecting newly added accounts.

        A Finicity `POST /connections/{connection_id}/refresh` updates
        accounts already held by LedgerSync. It does not open account
        selection or import an account that the user has not shared.

        ### What you get back

        A hosted `reauth_url`, a LedgerSync-hosted page the end-user opens
        to complete the source-specific flow (Finicity Connect Fix, MX
        member reconnect, FDE credential recapture) against the existing
        connection. Redirect the user to it; connection status changes
        produce `connection.active` / `connection.failed` webhooks.
        An already active connection may have no new status transition,
        so do not require another `connection.active` event to finish a
        no-op session.

        The response also carries `source`: the provider the URL leads to.
        See "Ids are not always stable" below.

        ### The URL is a reusable bearer credential

        The link is **not** single-use. It stays valid until
        `action.expires_at` (currently about six days out) and anyone
        holding it can open the end-user's bank-linking session. Deliver it
        over a channel you would use for a password reset, do not log it,
        and do not embed it in a page that a third party can scrape.

        ### Ids are not always stable

        Repairs aim to retain existing `con_` / `acc_` / `txn_` ids.
        Finicity can issue a different underlying login during repair;
        when that cannot be matched back to the existing connection, a
        separate connection can result even if the response `source`
        is unchanged. Re-list the Client's connections and accounts after
        the session instead of treating a matching `source` as proof of
        stable ids.

        For a bank LedgerSync now serves exclusively through a different
        provider, the URL we hand back is an add-bank link for that
        provider rather than a repair link for the connection you named.
        Today that is Finicity connections at such banks being redirected
        to MX, and American Express is on that list in production. The
        list is configuration and can change without an API version bump,
        so branch on the response rather than on a bank you hard-coded.

        When the redirect happens, the end-user's session creates a **new**
        connection with a new `con_` id and new `acc_` / `txn_` ids, and
        the connection you passed is left as it was.

        Detect it from the response: `source` differs from the source
        segment of the `connection_id` you sent. On that branch the
        `connection.active` webhook that follows carries the **new**
        connection's id, not the one you passed, so key off the Client
        rather than the connection: wait for `connection.active`, then
        re-list `GET /v3/clients/{client_id}/connections` and
        `GET /v3/accounts?client_id=...` and re-map, rather than expecting
        the old ids to come back.

        ### Call it because a person asked, not on a timer

        Each completed session can share accounts you were not syncing
        before, and newly shared accounts pull their statement history,
        which is billable. Trigger this from an explicit user action. Do
        not schedule it, do not retry it in a loop, and do not mint a
        second link while the first is still valid.

        Available for `FINICITY`, `MX`, and `FDE`. Uploaded-statement
        (`PDF`) data is read-only and has no connection to reauthorize
        (`400`). On `MX` and `FDE` you do not need this endpoint to pick up
        a newly opened account: a plain refresh discovers it. See
        `POST /connections/{connection_id}/refresh`.

        Ownership is enforced server-side: a `connection_id` that
        doesn't belong to the authenticated customer returns `404`.

        ### Empty-body POST

        This endpoint takes no request body. Send an explicit
        `Content-Length: 0` header so the upstream HTTPS load balancer
        doesn't reject the request with `411 Length Required`.
      operationId: reauthorizeConnection
      requestBody:
        required: false
        description: |
          No body. Send `Content-Length: 0` so the upstream load
          balancer doesn't reject the request with 411.
        content:
          application/json:
            schema:
              type: object
              nullable: true
      responses:
        '200':
          description: |
            A hosted reauthorization URL, plus the `source` it leads to.
            A different source means the URL starts a new connection.
            A matching source targets repair of the existing connection,
            but does not guarantee stable ids if Finicity changes the login.
          headers:
            X-LS-Trace-Id:
              $ref: '#/components/headers/X-LS-Trace-Id'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ConnectionReauthorization'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '411':
          description: |
            Returned by the upstream HTTPS load balancer when a POST
            arrives without a `Content-Length` header. Retry with
            `Content-Length: 0` set explicitly.
        '502':
          description: |
            The aggregator or the backend was unreachable while minting
            the reauthorization URL, so nothing was issued. Body carries
            the canonical `ErrorEnvelope` (typically
            `error.code = "upstream_unavailable"`); retry shortly.
          headers:
            X-LS-Trace-Id:
              $ref: '#/components/headers/X-LS-Trace-Id'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorEnvelope'
components:
  headers:
    X-LS-Trace-Id:
      description: Distributed-trace ID for this request. Quote in support tickets.
      schema:
        type: string
        example: 4bf92f3577b34da6a3ce929d0e0e4736
  schemas:
    ConnectionReauthorization:
      type: object
      description: |
        Result of `POST /v3/connections/{connection_id}/reauthorize`: the
        connection id (echoed for correlation), the source the hosted URL
        actually leads to, and a `reauthorize` action carrying that URL.
      required:
        - connection_id
        - source
        - action
      properties:
        connection_id:
          type: string
          example: con_FINICITY_41294
        source:
          allOf:
            - $ref: '#/components/schemas/Source'
          description: |
            The source the hosted URL leads to. Usually the same source as
            the `connection_id` you passed. Repairs aim to retain existing
            ids, but a matching source does not guarantee this: Finicity
            may issue a different login that cannot be matched back to the
            existing connection.

            When it differs, the URL hands the end-user to a different
            provider (today: a Finicity connection at a bank we now serve
            exclusively through MX). Completing it creates a **new**
            connection with a new `con_` id and new `acc_` / `txn_` ids
            under the same Client; the old connection is not repaired.
            Compare this against the source segment of the
            `connection_id` you sent, and if it differs, re-list
            `GET /v3/clients/{client_id}/connections` and
            `GET /v3/accounts?client_id=...`
            after the `connection.active` webhook rather than expecting
            the old ids to come back.
          example: FINICITY
        action:
          $ref: '#/components/schemas/ConnectionActionReauthorize'
    ErrorEnvelope:
      type: object
      description: |
        Error envelope returned as the top-level body of every non-2xx
        HTTP response. The actual error payload lives in the `error`
        field — branch on `error.code`.
      required:
        - error
      properties:
        error:
          $ref: '#/components/schemas/ErrorInfo'
    Source:
      type: string
      description: |
        Financial-data source backing an account. Aggregator sources
        (`FINICITY`, `MX`) and `FDE` back a Connection; `PDF` does not.

        Values:
        - `FINICITY` — Finicity aggregation
        - `MX` — MX aggregation
        - `FDE` — Financial Document Extraction (LedgerSync proprietary)
        - `PDF` — Uploaded bank statements. Read-only: exposed on
          `/accounts` and `/transactions` (statements are not served for
          PDF), and never as a Connection (PDF accounts have
          `connection_id: null`).
      enum:
        - FINICITY
        - MX
        - FDE
        - PDF
      x-enum-descriptions:
        - Finicity aggregation
        - MX aggregation
        - Financial Document Extraction (LedgerSync proprietary)
        - Uploaded bank statements (read-only; not a connection source)
    ConnectionActionReauthorize:
      type: object
      required:
        - kind
        - reauth_url
        - expires_at
      properties:
        kind:
          type: string
          enum:
            - reauthorize
        reauth_url:
          type: string
          format: uri
        expires_at:
          type: string
          format: date-time
    ErrorInfo:
      type: object
      description: |
        The inner error payload. Used as the top-level body of an
        HTTP error response (wrapped in `ErrorEnvelope`) and as the
        embedded `error` field on resources that record a failure
        (like `Operation.error`).
      required:
        - code
        - message
        - type
      properties:
        code:
          type: string
          description: |
            Stable machine-readable identifier. Branch on this in
            your code, not on `message`.
          example: unknown_api_key
        message:
          type: string
          description: Plain-English explanation safe to log.
          example: The API key you presented doesn't match any active key.
        doc_url:
          type: string
          format: uri
          description: |
            Link to the docs page for this specific error code.
            Shareable with teammates in support tickets.
          example: https://portal.ledgersyncappv2.com/errors/unknown_api_key
        type:
          type: string
          description: |
            Stripe-style broad failure-mode category — useful for
            "treat all of these the same way" branches. Derived
            from the HTTP status. Orthogonal to `category`, which
            classifies by origin.
          enum:
            - auth_error
            - invalid_request
            - rate_limit_error
            - idempotency_error
            - not_found
            - api_error
          example: auth_error
        category:
          type: string
          description: |
            Plaid-style coarse classification by origin. Branch on
            this for routing logic — retry the request, surface to
            the end user in the widget, or page on-call. Orthogonal
            to `type` (which is HTTP-status-derived).
          enum:
            - AUTH_ERROR
            - INSTITUTION_ERROR
            - CAPABILITY_UNAVAILABLE
            - CONNECTION_ERROR
            - RATE_LIMIT
            - INVALID_REQUEST
            - RESOURCE_NOT_FOUND
            - PLATFORM_ERROR
          example: AUTH_ERROR
        is_user_actionable:
          type: boolean
          description: |
            True when the end user can resolve this error (re-enter
            credentials, complete MFA, accept an updated
            agreement). False when the error requires
            institution-side or LS platform-side action. Useful for
            deciding whether to send the end user back to the
            widget or surface an "operational issue" banner.
          example: true
        source_diagnostic_code:
          type: string
          pattern: ^(FIN|MX|FDE)-[A-Z0-9_]+$
          description: |
            Opaque upstream-source diagnostic identifier (e.g.
            `FIN-103`, `MX-DENIED`). Present only on errors that
            originated at an aggregator/extractor. Use for support
            triage — do NOT branch on this value; the unified
            `code` and `category` are the integrator-facing
            vocabulary.
          example: FIN-103
        param:
          type: string
          description: |
            On every 400 or 413 that is about one request field
            (`validation_failed` and `invalid_request` alike), the
            field that tripped the check. Dot-separated path for
            nested fields, with array positions in brackets
            (`line.amount`, `items[1].amount`). Absent on errors that
            are not about a field (auth, not found, upstream faults).
            When the body itself could not be parsed there is no one
            field to blame: most endpoints omit `param`, and the few
            that parse the body themselves report the literal `body`.
          example: client.email
        trace_id:
          type: string
          description: |
            Same as the `X-LS-Trace-Id` response header — paste in
            a support ticket to jump to the request.
          example: 4bf92f3577b34da6a3ce929d0e0e4736
        errors:
          type: array
          description: |
            Per-field validation errors (only present on 400 when
            multiple fields failed at once).
          items:
            type: object
            required:
              - param
              - message
            properties:
              param:
                type: string
                example: client.email
              message:
                type: string
                example: must be a valid email address
              code:
                type: string
                example: invalid_email
  responses:
    BadRequest:
      description: |
        Something in the request body or query string didn't pass
        validation.

        Whenever the failure is about one field, `error.param` names
        it, under `error.code = validation_failed` and
        `error.code = invalid_request` alike, as a dot-separated path
        for nested fields (`line.amount`, `items[1].amount`). The same
        name is repeated inside `error.message` in the form
        `Field 'cursor': ...`, so either is usable, but `error.param`
        is the one to branch on.

        Schema validation additionally fills `error.errors[]` when
        several fields fail at once.

        `error.param` is absent when no single field is to blame: an
        error that isn't about a field (auth, not found, upstream
        faults), or a body that could not be parsed at all. In that
        last case a few endpoints that parse the body themselves
        report the literal `body` rather than omitting `param`;
        either way there is no field to highlight.
      headers:
        X-LS-Trace-Id:
          $ref: '#/components/headers/X-LS-Trace-Id'
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorEnvelope'
    Unauthorized:
      description: |
        Either the `Authorization` header is missing or the bearer
        token doesn't match an active API key. Double-check the key
        and the environment — sandbox keys can't be used against the
        production base URL and vice versa.
      headers:
        X-LS-Trace-Id:
          $ref: '#/components/headers/X-LS-Trace-Id'
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorEnvelope'
    NotFound:
      description: |
        We didn't find a resource matching the path parameters. Common
        causes: the id belongs to a different customer's key, the
        resource was deleted, or there's a typo in the id.
      headers:
        X-LS-Trace-Id:
          $ref: '#/components/headers/X-LS-Trace-Id'
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorEnvelope'
  securitySchemes:
    bearer:
      type: http
      scheme: bearer
      bearerFormat: LedgerSync API key
      description: |
        Pass your secret key in the `Authorization` header as a Bearer
        token: `Authorization: Bearer sk_test_...` (sandbox) or
        `Bearer sk_live_...` (production).

        Keys are created in the developer portal and the plaintext
        secret is shown exactly once at creation. Treat them like
        passwords — never embed them in mobile apps or front-end code.

````