Apply a one-time reconciliation baseline (migration cutover anchor)

Required API key scope: accounting:write

THE Baseline wizard executor (CLEARING-RECON-REENGINEER S6, 2026-07-01; Xero conversion-balance + NetSuite go-live pattern). In ONE database transaction it:

1. creates a COMPLETED system reconciliation session (“Migration baseline”) at baseline_date / baseline_balance,
2. bulk-marks the bank GL’s unreconciled POSTED journal lines dated on or before baseline_date as reconciled — EXCEPT the operator-kept in-transit keep_open_gl_line_ids,
3. bulk-excludes (exclude_reason='pre_baseline') unreconciled bank feed lines dated on or before baseline_date — EXCEPT keep_open_bank_txn_ids,
4. stamps reconciliation_baseline_date + baseline_balance on the bank account (which then seeds new sessions’ opening balance),
5. returns the flip/exclude counts + the variance math.

Variance proof: variance = baseline_balance - (posted GL balance at the anchor - kept-open in-transit total). A variance beyond $0.01 returns 422 with the full math unless force: true.

Guards: 409 baseline_already_exists when a different baseline is already stamped (re-running with the SAME date + balance is idempotent and returns the existing session with already_applied: true); 409 reconciliation_in_progress when an open session exists (cancel it first via PATCH /accounting/reconciliations/).

Posts ZERO GL. The only GL-adjacent effect is journal_entry_lines.reconciled_at flips (the same GL-neutral signal a normal match writes). No closed-period guard applies (the anchor date is usually historical and nothing is posted).

Supports the Idempotency-Key header (canonical api-v1 mutation contract) in addition to the parameter-level idempotency above.

POST /bank-accounts/{id}/reconciliation-baseline

Apply a one-time reconciliation baseline (migration cutover anchor)

cURL

curl --request POST \
  --url https://api.arcuserp.com/v1/bank-accounts/{id}/reconciliation-baseline \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "baseline_date": "2023-12-25",
  "baseline_balance": 123,
  "keep_open_gl_line_ids": [
    "3c90c3cc-0d44-4b50-8888-8dd25736052a"
  ],
  "keep_open_bank_txn_ids": [
    "3c90c3cc-0d44-4b50-8888-8dd25736052a"
  ],
  "force": true,
  "notes": "<string>"
}
'

import requests

url = "https://api.arcuserp.com/v1/bank-accounts/{id}/reconciliation-baseline"

payload = {
    "baseline_date": "2023-12-25",
    "baseline_balance": 123,
    "keep_open_gl_line_ids": ["3c90c3cc-0d44-4b50-8888-8dd25736052a"],
    "keep_open_bank_txn_ids": ["3c90c3cc-0d44-4b50-8888-8dd25736052a"],
    "force": True,
    "notes": "<string>"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    baseline_date: '2023-12-25',
    baseline_balance: 123,
    keep_open_gl_line_ids: ['3c90c3cc-0d44-4b50-8888-8dd25736052a'],
    keep_open_bank_txn_ids: ['3c90c3cc-0d44-4b50-8888-8dd25736052a'],
    force: true,
    notes: '<string>'
  })
};

fetch('https://api.arcuserp.com/v1/bank-accounts/{id}/reconciliation-baseline', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.arcuserp.com/v1/bank-accounts/{id}/reconciliation-baseline",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'baseline_date' => '2023-12-25',
    'baseline_balance' => 123,
    'keep_open_gl_line_ids' => [
        '3c90c3cc-0d44-4b50-8888-8dd25736052a'
    ],
    'keep_open_bank_txn_ids' => [
        '3c90c3cc-0d44-4b50-8888-8dd25736052a'
    ],
    'force' => true,
    'notes' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.arcuserp.com/v1/bank-accounts/{id}/reconciliation-baseline"

	payload := strings.NewReader("{\n  \"baseline_date\": \"2023-12-25\",\n  \"baseline_balance\": 123,\n  \"keep_open_gl_line_ids\": [\n    \"3c90c3cc-0d44-4b50-8888-8dd25736052a\"\n  ],\n  \"keep_open_bank_txn_ids\": [\n    \"3c90c3cc-0d44-4b50-8888-8dd25736052a\"\n  ],\n  \"force\": true,\n  \"notes\": \"<string>\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.arcuserp.com/v1/bank-accounts/{id}/reconciliation-baseline")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"baseline_date\": \"2023-12-25\",\n  \"baseline_balance\": 123,\n  \"keep_open_gl_line_ids\": [\n    \"3c90c3cc-0d44-4b50-8888-8dd25736052a\"\n  ],\n  \"keep_open_bank_txn_ids\": [\n    \"3c90c3cc-0d44-4b50-8888-8dd25736052a\"\n  ],\n  \"force\": true,\n  \"notes\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.arcuserp.com/v1/bank-accounts/{id}/reconciliation-baseline")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"baseline_date\": \"2023-12-25\",\n  \"baseline_balance\": 123,\n  \"keep_open_gl_line_ids\": [\n    \"3c90c3cc-0d44-4b50-8888-8dd25736052a\"\n  ],\n  \"keep_open_bank_txn_ids\": [\n    \"3c90c3cc-0d44-4b50-8888-8dd25736052a\"\n  ],\n  \"force\": true,\n  \"notes\": \"<string>\"\n}"

response = http.request(request)
puts response.read_body

200

{
  "data": {
    "already_applied": true,
    "baseline_date": "2023-12-25",
    "baseline_balance": 123,
    "reconciliation": {}
  }
}

{
  "data": {
    "reconciliation": {},
    "baseline_date": "2023-12-25",
    "baseline_balance": 123,
    "gl_lines_reconciled": 123,
    "bank_transactions_excluded": 123,
    "kept_open_gl_line_count": 123,
    "kept_open_bank_txn_count": 123,
    "math": {
      "gl_balance_at_baseline": 123,
      "kept_open_total": 123,
      "cleared_balance": 123,
      "variance": 123
    }
  }
}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

{
  "error": "not_found",
  "code": "not_found",
  "type": "not_found",
  "hint": "The requested order does not exist or does not belong to this entity.",
  "param": "expand[0]",
  "required": "accounts:read",
  "request_id": "req_abc123"
}

{
  "error": "baseline_variance_nonzero",
  "code": "<string>",
  "baseline_balance": 123,
  "gl_balance_at_baseline": 123,
  "kept_open_total": 123,
  "cleared_balance": 123,
  "variance": 123,
  "hint": "<string>"
}

Authorizations

Authorization · string · header · required

API key issued per entity via Settings > Developers > API Keys. Each key carries scopes (e.g. orders:read, products:write). Bearer token format: Authorization: Bearer ark_live_ent_Test keys use ark_test_ent_. Both are issued per entity
via Settings > Developers > API Keys.

Path Parameters

id · string<uuid> · required

Bank account UUID.

Body

application/json

baseline_date · string<date> · required

The cutover/anchor date (YYYY-MM-DD).

baseline_balance · number · required

The REAL bank statement balance at the anchor date.

keep_open_gl_line_ids · string<uuid>[]

Journal-entry-line UUIDs to KEEP unreconciled (in-transit checks/deposits not yet cleared at the anchor).

keep_open_bank_txn_ids · string<uuid>[]

Bank transaction UUIDs to KEEP unexcluded (feed lines that must remain matchable).

force · boolean

Accept a nonzero anchor variance (default false -> 422 when |variance| > $0.01).

notes · string | null

Appended to the system session's notes (capped 500 chars).

Response

200

application/json

Idempotent re-run (same date + balance already stamped)

data · object

Show child attributes