> ## Documentation Index > Fetch the complete documentation index at: https://docs.billbuddyhq.com/llms.txt > Use this file to discover all available pages before exploring further. # Obtain an OAuth access token > Obtains an access token using OAuth2 client_credentials. Client credentials must be approved, enabled, not revoked and not expired. If an IP allowlist is configured, business requests must originate from an approved IP. Use the Client Secret and access_token only on the merchant server. Request a new token when it expires; no refresh_token is provided. Token requests are limited to 60 per minute; exceeding the limit returns HTTP 429. ## OpenAPI ````yaml /openapi/billbuddy-v2-openapi.en.yaml post /oauth/token openapi: 3.0.3 info: title: BillBuddy API Integration Guide version: 2.0.0 description: > BillBuddy API integration guide. It covers authentication, transaction and subscription endpoints called by third-party servers. Request and response examples contain complete fictional business data and tokens generated offline; they cannot authenticate or initiate real transactions. ## Getting started 1. Obtain your Client ID, Client Secret, merchant identifier and business identifier from BillBuddy. If an IP allowlist applies, send requests from an approved fixed outbound IP address. 2. Obtain an access_token through POST /oauth/token. Business requests require Authorization: Bearer {access_token} and Accept: application/json. Use Content-Type: application/json for JSON requests and form encoding for token requests. 3. Call the payment or subscription endpoints as needed. Customers open the hosted activation page through activation_url. Store the Client Secret only on your server. ## Identifiers and amounts OAuth credentials identify the merchant; business_id is not a request parameter. Endpoints that require a business use merchant_id. For single-transaction and batch-result lookups, merchant_id is optional; omit it or leave it empty to search all businesses of the authenticated merchant. The transaction list uses optional, case-sensitive Mid; omit it to query all businesses belonging to the authenticated merchant. A requested business must belong to that merchant. Read response identifiers according to each endpoint's field definitions. TXT file amounts, amount_cents and declared_total_amount_cents use cents. Other amounts use major currency units with at most two decimal places: 10.50 means AUD 10.50. Use strings for bank account numbers, card numbers, months, years and postcodes to preserve leading zeros. ## Success and failure Business JSON responses use code=0 for success and code=1 for ordinary failures. Transaction and subscription validation failures usually return code=400 and data={} with HTTP 200. V2 business endpoint authentication failures use code=1. A missing, malformed or inaccessible business merchant_id for plan/list return code=1. HTTP 429 indicates a rate limit. The OAuth endpoint uses standard OAuth responses with HTTP 200/400/401/429. code=0 means the API request was processed successfully; assess the payment outcome separately. Batch accepted means the request was accepted for asynchronous processing. Bank Pending, scheduled Pending and outstanding 3DS authentication do not indicate payment success. Transactions, DDR subscriptions and payment schedules use different status enumerations; refer to their field definitions. ## Dates and frequencies Use YYYY-MM-DD for request dates. Today and tomorrow are evaluated in Australia/Sydney, including daylight saving time. Scheduled cancellations also use Australia/Sydney: cancellation must occur strictly before 08:15 on the processing date; it is no longer permitted at that time. Payment complete_date and checkout expires_at use DD/MM/YYYY HH:mm:ss. Refer to individual fields for other formats. Standard RRULE examples: Daily FREQ=DAILY;INTERVAL=1; Weekly FREQ=WEEKLY;INTERVAL=1;BYDAY=MO; Fortnightly FREQ=WEEKLY;INTERVAL=2;BYDAY=MO; Monthly FREQ=MONTHLY;INTERVAL=1;BYMONTHDAY=15; Quarterly FREQ=MONTHLY;INTERVAL=3;BYMONTHDAY=15; Half Yearly FREQ=MONTHLY;INTERVAL=6;BYMONTHDAY=15; Yearly FREQ=YEARLY;INTERVAL=1;BYMONTH=2;BYMONTHDAY=15. Weekday abbreviations are MO/TU/WE/TH/FR/SA/SU. Weekly/Monthly rules without a specific debit day derive it from the start date. A single BYDAY=SA or SU is treated as Monday; a weekend start date without an explicit debit day is also treated as Monday. A single BYMONTHDAY=29/30/31 falls on the last day of shorter months; BYMONTHDAY=-1 means the last day of the month. All rules must be valid RRULE expressions. For a nonstandard frequency such as every 10 days, provide process_type=12, custom_cycle_type=1, custom_cycle=10 and day_of_debit=FREQ=DAILY;INTERVAL=10. Units 1/2/3/4 correspond to DAILY/WEEKLY/MONTHLY/YEARLY. The minimum interval is 5 for days and 1 for other units. INTERVAL must equal custom_cycle. Quarterly, half-yearly and yearly schedules also require day_of_debit_dtstart. Its complete date must be strictly after the start_date of the same schedule segment and within one billing cycle after it. The first actual debit date for createSchedule depends on the DDR start date, debit frequency and the requirement that it be no earlier than tomorrow. ## Using examples Schemas define types, nullability, lengths, enumerations and numeric ranges. Field descriptions define conditional requirements, dates and business restrictions. Use both together. Set BASE_URL, ACCESS_TOKEN, CLIENT_ID and CLIENT_SECRET before running curl examples. BillBuddy provides the actual test and production domains. Replace example customers, orders, cards, accounts and dates with values permitted in your test environment and satisfying the date restrictions. ## Hosted subscription integration Call POST /api/v2/subscription/create, then use the complete activation_url unchanged for a browser redirect or an iframe src. Alternatively, use activation_html as the iframe srcdoc. Customers enter payment information, authorize debits and activate the subscription on the BillBuddy-hosted page. Use the full returned URL; do not construct it yourself or parse its credentials. Keep the Client Secret and access_token on your server; never include them in iframe URLs or page contents. Recurring and By agreement subscriptions must be activated before start_date. One-off-only subscriptions must be submitted for activation within 30 days of creation. An accessible page does not guarantee submission is still permitted; the activation response is authoritative. ## Example data conventions Example merchants, customers, orders, payment tokens, session links and OAuth credentials are fictional and cannot be used for real requests. Card numbers are standard test card numbers; bank accounts are fictional. Email addresses use the reserved example.com domain, and phone numbers use Australian numbers reserved for examples. Replace BASE_URL, ACCESS_TOKEN, CLIENT_ID and CLIENT_SECRET with actual values from your approved test environment. Empty strings, null, empty arrays, 0 and false represent meaningful API states in some examples and must not be replaced indiscriminately. Payment response signatures are calculated offline according to the signing rules for each payment scenario, using the public demo key bb_docs_demo_signing_key_2030. The html field is excluded for responses awaiting 3DS authentication. This key is for documentation only and cannot sign or authenticate real requests. ## TXT batch transactions Upload fixed-width TXT files using multipart/form-data. File amounts, amount_cents and declared_total_amount_cents use cents, excluding surcharges; see “Upload a TXT transaction file” for the format and example file. Upload success only confirms acceptance. Retain batch_id and file_identifier and use the batch result endpoint to check individual outcomes. Batch completed does not mean every payment succeeded. Use OAuth credentials for the same merchant to query results. merchant_id is optional; when supplied, it must match the business identifier in the original upload. Response identifiers follow the definitions for each endpoint. ## Request examples by programming language Examples are provided in cURL, Python, JavaScript, PHP, Go, Java and Ruby, with the same business scenarios available in each language. Each example preserves the parameters and types from its corresponding cURL scenario. Requirements: cURL; Python 3.9+ (standard library); JavaScript with Node.js 18+, saved as an .mjs file; PHP 8+ with the cURL extension; Go 1.20+; Java 11+ (save the Example class as Example.java); Ruby 3+ (standard library). Set BASE_URL before running examples. Business endpoints also require ACCESS_TOKEN; token requests require CLIENT_ID and CLIENT_SECRET. BASE_URL is the API root without /api/v2. TXT upload examples read payments.txt from the current directory. Replace fictional values with approved test data and assess the response code and business status separately. servers: - url: https://staging-api.billbuddyhq.com description: Staging environment security: - oauth2: [] tags: - name: Authentication description: OAuth2 Client Credentials。 - name: Transactions description: Single payments, batch payments and scheduled payment cancellations. - name: Subscriptions description: >- Subscription templates, hosted subscription creation, DDR creation and activation, and payment schedule submission. paths: /oauth/token: post: tags: - Authentication summary: Obtain an OAuth access token description: >- Obtains an access token using OAuth2 client_credentials. Client credentials must be approved, enabled, not revoked and not expired. If an IP allowlist is configured, business requests must originate from an approved IP. Use the Client Secret and access_token only on the merchant server. Request a new token when it expires; no refresh_token is provided. Token requests are limited to 60 per minute; exceeding the limit returns HTTP 429. operationId: oauthClientCredentialsToken requestBody: required: true content: application/x-www-form-urlencoded: schema: $ref: '#/components/schemas/OAuthTokenRequest' example: grant_type: client_credentials client_id: 8a6bf2d9-47c1-4e85-92b3-6d1a7c084f52 client_secret: d9K7wR2mN8vT4xQ6aH3cF5jL1sB0eG9pY7uV2zC4 responses: '200': description: Token issued successfully. content: application/json: schema: $ref: '#/components/schemas/OAuthTokenResponse' example: token_type: Bearer expires_in: 7200 access_token: >- eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJhdWQiOiI4YTZiZjJkOS00N2MxLTRlODUtOTJiMy02ZDFhN2MwODRmNTIiLCJqdGkiOiJhZGRiNDgzNDkxMGM2MThjZmJiNGRhMTJhZDMwNWEwNGU3ZmZiNWUzMTE3YjI3YmQwNTVlMjk5ZTgzOTU1ZTkyIiwiaWF0IjoxODkzNDUyNDAwLCJuYmYiOjE4OTM0NTI0MDAsImV4cCI6MTg5MzQ1OTYwMCwic3ViIjoiOGE2YmYyZDktNDdjMS00ZTg1LTkyYjMtNmQxYTdjMDg0ZjUyIiwic2NvcGVzIjpbXX0.dLrN3edou1KGfN5a2kbfDRtGA-iM4meEfwlMTPc1UHv1wGrv70ue8Mb3UU0TYxbZHxK-kHHUVH9aWwItbsyYBkou3Sgr5NAwejvuxSOmQZHk4dT-Uw982pelDqBrBmJV5qZ5qY7qeGDc0Fz_0ymre50BLOd2d3MsLj-INdwjNNIF4fr2AG9M6mDK8pEqGMNMqT20GGVEQ1YJZGwpy-XiPp-6sVS3qOjyineqTK_hN3N0QXykoEM4iFGK_wQdc681B8tfXJRpcQksNt4A1pM2G5nUdnBC-ahByGYUaij4JAkxR_LpnXoR1xQbd-j4wj8cG78WAPdJTzZcIFPRU0Gmjw '400': description: Missing parameters, invalid grant type or invalid scope. content: application/json: schema: $ref: '#/components/schemas/OAuthError' example: error: invalid_request error_description: >- The request is missing a required parameter, includes an invalid parameter value, includes a parameter more than once, or is otherwise malformed. hint: Check the `grant_type` parameter '401': description: >- Client authentication failed or the client is unavailable for business requests. content: application/json: schema: $ref: '#/components/schemas/OAuthError' example: error: invalid_client error_description: Client authentication failed '429': description: >- Token request rate limit exceeded: at most 60 requests per minute. Wait as directed by Retry-After before retrying. headers: Retry-After: description: Seconds to wait before retrying. schema: type: integer content: application/json: schema: type: object description: Rate limit response. properties: message: type: string description: Rate limit message. example: message: Too Many Attempts. security: [] x-codeSamples: - lang: Shell label: Client credentials source: |- curl -X POST "${BASE_URL}/oauth/token" \ -H "Accept: application/json" \ -H "Content-Type: application/x-www-form-urlencoded" \ --data-urlencode "grant_type=client_credentials" \ --data-urlencode "client_id=${CLIENT_ID}" \ --data-urlencode "client_secret=${CLIENT_SECRET}" - lang: Python label: Client credentials source: > import json import os import urllib.parse import urllib.request base_url = os.environ["BASE_URL"].rstrip("/") url = base_url + "/oauth/token" headers = {"Accept": "application/json"} params = { "grant_type": "client_credentials", "client_id": os.environ["CLIENT_ID"], "client_secret": os.environ["CLIENT_SECRET"], } body = urllib.parse.urlencode(params).encode("utf-8") headers["Content-Type"] = "application/x-www-form-urlencoded" request = urllib.request.Request(url, data=body, headers=headers, method="POST") with urllib.request.urlopen(request, timeout=30) as response: print(response.read().decode("utf-8")) - lang: JavaScript label: Client credentials source: | const env = (name) => { const value = process.env[name]; if (!value) throw new Error(`Missing environment variable: ${name}`); return value; }; const baseUrl = env("BASE_URL").replace(/\/+$/, ""); const url = new URL(baseUrl + "/oauth/token"); const headers = { Accept: "application/json" }; const params = new URLSearchParams({ "grant_type": "client_credentials", "client_id": env("CLIENT_ID"), "client_secret": env("CLIENT_SECRET"), }); const body = params; headers["Content-Type"] = "application/x-www-form-urlencoded"; const response = await fetch(url, { method: "POST", headers, body, signal: AbortSignal.timeout(30_000), }); console.log(await response.text()); - lang: PHP label: Client credentials source: | "client_credentials", "client_id" => $env("CLIENT_ID"), "client_secret" => $env("CLIENT_SECRET"), ]; $body = http_build_query($params, '', '&', PHP_QUERY_RFC3986); $headers[] = 'Content-Type: application/x-www-form-urlencoded'; $curl = curl_init($url); curl_setopt_array($curl, [ CURLOPT_CUSTOMREQUEST => "POST", CURLOPT_HTTPHEADER => $headers, CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 30, CURLOPT_POSTFIELDS => $body, ]); $response = curl_exec($curl); if ($response === false) { $error = curl_error($curl); curl_close($curl); throw new RuntimeException($error); } curl_close($curl); echo $response, PHP_EOL; - lang: Go label: Client credentials source: | package main import ( "fmt" "io" "net/http" "net/url" "os" "strings" "time" ) func mustEnv(name string) string { value := os.Getenv(name) if value == "" { panic("Missing environment variable: " + name) } return value } func main() { baseURL := strings.TrimRight(mustEnv("BASE_URL"), "/") endpoint := baseURL + "/oauth/token" params := url.Values{} params.Set("grant_type", "client_credentials") params.Set("client_id", mustEnv("CLIENT_ID")) params.Set("client_secret", mustEnv("CLIENT_SECRET")) body := strings.NewReader(params.Encode()) req, err := http.NewRequest("POST", endpoint, body) if err != nil { panic(err) } req.Header.Set("Accept", "application/json") req.Header.Set("Content-Type", "application/x-www-form-urlencoded") client := &http.Client{Timeout: 30 * time.Second} response, err := client.Do(req) if err != nil { panic(err) } defer response.Body.Close() result, err := io.ReadAll(response.Body) if err != nil { panic(err) } fmt.Println(string(result)) } - lang: Java label: Client credentials source: | import java.io.ByteArrayOutputStream; import java.net.URI; import java.net.URLEncoder; import java.net.http.HttpClient; import java.net.http.HttpRequest; import java.net.http.HttpResponse; import java.nio.charset.StandardCharsets; import java.nio.file.Files; import java.nio.file.Path; import java.time.Duration; import java.util.LinkedHashMap; import java.util.Map; import java.util.UUID; import java.util.stream.Collectors; public class Example { static String requireEnv(String name) { String value = System.getenv(name); if (value == null || value.isEmpty()) { throw new IllegalArgumentException("Missing environment variable: " + name); } return value; } public static void main(String[] args) throws Exception { String baseUrl = requireEnv("BASE_URL").replaceAll("/+$", ""); String endpoint = baseUrl + "/oauth/token"; Map params = new LinkedHashMap<>(); params.put("grant_type", "client_credentials"); params.put("client_id", requireEnv("CLIENT_ID")); params.put("client_secret", requireEnv("CLIENT_SECRET")); String encoded = params.entrySet().stream() .map(e -> URLEncoder.encode(e.getKey(), StandardCharsets.UTF_8) + "=" + URLEncoder.encode(e.getValue(), StandardCharsets.UTF_8)) .collect(Collectors.joining("&")); HttpRequest.Builder builder = HttpRequest.newBuilder(URI.create(endpoint)) .timeout(Duration.ofSeconds(30)) .header("Accept", "application/json"); builder.header("Content-Type", "application/x-www-form-urlencoded"); HttpRequest request = builder.method("POST", HttpRequest.BodyPublishers.ofString(encoded, StandardCharsets.UTF_8)).build(); HttpClient client = HttpClient.newBuilder().connectTimeout(Duration.ofSeconds(30)).build(); HttpResponse response = client.send(request, HttpResponse.BodyHandlers.ofString(StandardCharsets.UTF_8)); System.out.println(response.body()); } } - lang: Ruby label: Client credentials source: | require "net/http" require "uri" base_url = ENV.fetch("BASE_URL").sub(%r{/+$}, "") uri = URI(base_url + "/oauth/token") params = { "grant_type" => "client_credentials", "client_id" => ENV.fetch("CLIENT_ID"), "client_secret" => ENV.fetch("CLIENT_SECRET"), } request = Net::HTTP::Post.new(uri) request["Accept"] = "application/json" request.set_form_data(params) http = Net::HTTP.new(uri.host, uri.port) http.use_ssl = uri.scheme == "https" http.open_timeout = 30 http.read_timeout = 30 puts http.request(request).body components: schemas: OAuthTokenRequest: type: object description: OAuth form. properties: grant_type: type: string description: Grant type. Always client_credentials. enum: - client_credentials minLength: 1 client_id: type: string description: OAuth Client ID assigned by BillBuddy. Submit as a string. minLength: 1 client_secret: type: string description: OAuth Client Secret. Store only on the merchant server. minLength: 1 scope: type: string description: Optional space-separated scopes. Usually omitted or an empty string. default: '' required: - grant_type - client_id - client_secret OAuthTokenResponse: type: object description: >- Standard OAuth success response. Does not contain code/message/data and does not return refresh_token. properties: token_type: type: string description: Always Bearer. enum: - Bearer expires_in: type: integer description: >- Token lifetime in seconds. Use the actual response; the example is 7200 seconds. access_token: type: string description: >- OAuth access_token. Include it in the Authorization: Bearer header on subsequent requests. required: - token_type - expires_in - access_token OAuthError: type: object description: Standard OAuth error without the business response envelope. properties: error: type: string description: OAuth error code. error_description: type: string description: Error description. hint: type: string description: Optional troubleshooting hint. message: type: string description: Optional error message. required: - error - error_description securitySchemes: oauth2: type: oauth2 description: >- OAuth2 client_credentials authorization. Obtain a new access_token when it expires. flows: clientCredentials: tokenUrl: /oauth/token scopes: {} ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.