API for Ninja Forms

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API for Ninja Forms

by sightfactory

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Description

API for Ninja Forms is the best, most powerful, and feature-complete REST API solution for Ninja Forms. Effortlessly export and integrate your form submissions with external applications, webhooks, and analytics platforms with unparalleled speed, reliability, and security.

Whether you need automated Excel reporting, instant PDF downloads, structured JSON data feeds, or real-time data synchronization, API for Ninja Forms delivers a best-in-class integration experience built for modern developers and business workflows.

Why API for Ninja Forms is the Best Choice:

  • Forms Discovery Endpoint: Query authorized forms, submission counts, and field definitions with strict per-key access control.
  • Cursor & Offset Pagination: Seamlessly paginate large historical datasets with page/per_page or cursor sync via since_id/before_id.
  • Single Record Retrieval: Instant lookup of specific submissions (/form/{id}/submission/{sub_id}) with cross-form ownership validation.
  • Unparalleled Multi-Format Exports: Stream submissions on-demand in 6 versatile formats: JSON, Excel (XLSX), PDF document reports, CSV spreadsheets, XML, and NDJSON/JSONL.
  • Military-Grade Payload Encryption: Protect sensitive customer and form data with state-of-the-art AEAD response encryption (AES-256-GCM, AES-128-GCM, and Sodium Secretbox).
  • Advanced Rate Limiting Protection: Safeguard your server against scraping, probing, and brute-force key exploitation with admin-controlled rate limits per minute, hour, or day.
  • Granular Form Access Control: Issue form-specific API keys with instant 1-click test suite tools and single-page key management.
  • Lightning-Fast & Ultra-Optimized: Zero-overhead streaming designed for high throughput, low memory footprint, and maximum performance.

Usage

1. Authentication

Pass your API key in the standard HTTP Authorization header:
Authorization: Bearer YOUR_API_KEY

2. Available Endpoints

  • Discover Authorized Forms:
    GET /wp-json/nf-submissions/v1/forms
    Returns all forms the authenticated key is authorized to access, with total submission counts and field counts.

  • Retrieve Submissions (with Pagination & Sorting):
    GET /wp-json/nf-submissions/v1/form/{form_id}
    Query parameters:

    • page (default: 1): Page number for offset pagination.
    • per_page / limit (default: 50, max: 500): Number of records per page.
    • offset: Explicit record offset (overrides page).
    • since_id / after_id: Retrieve only submissions with ID greater than this value (cursor pagination).
    • before_id / max_id: Retrieve only submissions with ID less than this value.
    • order: asc (default) or desc.
    • orderby: date (default), id, title, or modified.
    • begin_date & end_date: Filter by submission date range (YYYY-MM-DD).
    • format: json (default), csv, xlsx, pdf, xml, or jsonl.
  • Retrieve Single Submission:
    GET /wp-json/nf-submissions/v1/form/{form_id}/submission/{submission_id}
    Returns the exact submission record. Validates that the submission belongs to the specified form.

  • Retrieve Form Field Metadata:
    GET /wp-json/nf-submissions/v1/form/{form_id}/fields
    Returns the list of field labels, keys, and types for the specified form.

3. Pagination & Headers

When retrieving submissions in JSON format, standard pagination headers are included in the response:
* X-WP-Total: Total count of matching submissions.
* X-WP-TotalPages: Total calculated pages.
* X-WP-Page: Current page number.
* X-WP-PerPage: Records per page limit.
* X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset: Rate-limiting status (if enabled).

4. Payload Encryption & Decryption

When payload encryption is enabled on an API key:
* Text Feeds (JSON, CSV, XML, JSONL): Encrypted as a JSON envelope containing iv, tag, and ciphertext.
* Binary Streams (PDF, XLSX): Delivered as raw binary (.enc extension) with cryptographic headers (X-Crypto-IV, X-Crypto-Tag, X-Crypto-Nonce, X-Crypto-Algorithm).

5. PHP Code Examples (cURL & wp_remote_get)

  • Discover Authorized Forms via Native PHP cURL:
    `php
    $ch = curl_init( ‘https://example.com/wp-json/nf-submissions/v1/forms’ );
    curl_setopt_array( $ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
    ‘Authorization: Bearer YOUR_API_KEY’,
    ‘Accept: application/json’,
    ],
    ] );
    $response = curl_exec( $ch );
    $http_status = curl_getinfo( $ch, CURLINFO_HTTP_CODE );
    curl_close( $ch );

$data = json_decode( $response, true );

// Graceful error handling for invalid API key or server error
if ( 200 !== $http_status || ! is_array( $data ) || isset( $data[‘code’] ) ) {
$error = $data[‘message’] ?? ‘Failed to retrieve forms’;
exit( “API Error ({$http_status}): {$error}\n” );
}

foreach ( $data as $form ) {
echo “Form ID: {$form[‘id’]} | Title: {$form[‘title’]} | Submissions: {$form[‘submissions_count’]}\n”;
}
`

  • Fetch Submissions via Native PHP cURL (External Apps / Scripts):
    `php
    $ch = curl_init( ‘https://example.com/wp-json/nf-submissions/v1/form/1?page=1&per_page=50’ );
    curl_setopt_array( $ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
    ‘Authorization: Bearer YOUR_API_KEY’,
    ‘Accept: application/json’,
    ],
    ] );
    $response = curl_exec( $ch );
    $http_status = curl_getinfo( $ch, CURLINFO_HTTP_CODE );
    curl_close( $ch );

$data = json_decode( $response, true );

if ( 200 !== $http_status || ! is_array( $data ) || isset( $data[‘code’] ) ) {
$error = $data[‘message’] ?? ‘Failed to retrieve submissions’;
exit( “API Error ({$http_status}): {$error}\n” );
}

$submissions = $data;
`

  • Download Binary PDF / Excel (.xlsx) File via Native PHP cURL:
    `php
    $ch = curl_init( ‘https://example.com/wp-json/nf-submissions/v1/form/1?format=pdf’ );
    curl_setopt_array( $ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_HTTPHEADER => [
    ‘Authorization: Bearer YOUR_API_KEY’,
    ],
    ] );
    $file_contents = curl_exec( $ch );
    $http_status = curl_getinfo( $ch, CURLINFO_HTTP_CODE );
    curl_close( $ch );

if ( 200 === $http_status ) {
file_put_contents( ‘submissions.pdf’, $file_contents );
} else {
$error = json_decode( $file_contents, true );
echo “API Error ({$http_status}): ” . ( $error[‘message’] ?? ‘Download failed’ ) . “\n”;
}
`

  • Discover Authorized Forms via WordPress HTTP API (wp_remote_get):
    `php
    $response = wp_remote_get( ‘https://example.com/wp-json/nf-submissions/v1/forms’, [
    ‘headers’ => [ ‘Authorization’ => ‘Bearer YOUR_API_KEY’ ],
    ] );

if ( is_wp_error( $response ) ) {
exit( ‘Network Error: ‘ . $response->get_error_message() );
}

$status = wp_remote_retrieve_response_code( $response );
$data = json_decode( wp_remote_retrieve_body( $response ), true );

// Graceful error handling for invalid API key or server error
if ( 200 !== $status || ! is_array( $data ) || isset( $data[‘code’] ) ) {
$error = $data[‘message’] ?? ‘Failed to retrieve forms’;
exit( “API Error ({$status}): {$error}\n” );
}

foreach ( $data as $form ) {
echo “Form ID: {$form[‘id’]} | Title: {$form[‘title’]} | Submissions: {$form[‘submissions_count’]}\n”;
}
`

  • Fetch Submissions via WordPress HTTP API (wp_remote_get):
    `php
    $response = wp_remote_get( ‘https://example.com/wp-json/nf-submissions/v1/form/1’, [
    ‘headers’ => [ ‘Authorization’ => ‘Bearer YOUR_API_KEY’ ],
    ] );

if ( is_wp_error( $response ) ) {
exit( ‘Network Error: ‘ . $response->get_error_message() );
}

$status = wp_remote_retrieve_response_code( $response );
$data = json_decode( wp_remote_retrieve_body( $response ), true );

if ( 200 !== $status || ! is_array( $data ) || isset( $data[‘code’] ) ) {
$error = $data[‘message’] ?? ‘Failed to retrieve submissions’;
exit( “API Error ({$status}): {$error}\n” );
}

$submissions = $data;
`

Third-Party Resources

This plugin bundles and utilizes the following open-source library:

Support

For support and feature requests, please visit https://sightfactory.com

  1. Download the plugin ZIP file.
  2. Upload the extracted folder to the /wp-content/plugins/ directory.
  3. Activate the plugin through the ‘Plugins’ menu in WordPress.
  4. Generate a REST API key by navigating to Settings > NF API Keys.
  5. Make authenticated REST requests by including the header: Authorization: Bearer YOUR_API_KEY.
  1. Granular API key management with per-form access controls, expiration dates, and rate limits.

    Granular API key management with per-form access controls, expiration dates, and rate limits.

  2. End-to-end response payload encryption (AES-256-GCM & Sodium Secretbox) with secret key controls.

    End-to-end response payload encryption (AES-256-GCM & Sodium Secretbox) with secret key controls.

  3. Interactive developer documentation with ready-to-use PHP, JavaScript, and cURL examples.

    Interactive developer documentation with ready-to-use PHP, JavaScript, and cURL examples.

What API file formats are supported?

JSON, CSV, XLSX (Microsoft Excel), PDF, XML, and NDJSON/JSONL formats are supported.

How do I synchronize new submissions in real-time?

Use cursor pagination with ?since_id={last_synced_id}&order=asc. Your application only receives new submissions created since the last sync.

How do I enable response payload encryption?

Navigate to Settings > NF API Keys in your WordPress dashboard, check “Enable Response Payload Encryption”, select your cipher strategy (AES-256-GCM, AES-128-GCM, or Sodium Secretbox), and generate a key. Keep your secret decryption key safe.

Why does an encrypted PDF or XLSX file end in .enc?

Binary files exported with encryption enabled are saved with a .enc file extension (e.g., form-1-submissions-encrypted.pdf.enc). Because the file content consists of raw encrypted bytes, attempting to open the file directly in Adobe Reader or Microsoft Excel without decrypting it first will report a corrupted file error. The .enc extension clearly indicates that the file must be decrypted using your secret key first.

How do I decrypt binary files (PDF & XLSX) using PHP?

Read the binary body and HTTP response headers (X-Crypto-IV, X-Crypto-Tag):
`php
$response = wp_remote_get(‘https://example.com/wp-json/nf-submissions/v1/form/1?format=pdf’, [
‘headers’ => [‘Authorization’ => ‘Bearer YOUR_API_KEY’]
]);

if ( is_wp_error( $response ) || 200 !== wp_remote_retrieve_response_code( $response ) ) {
exit( ‘Download failed or unauthorized.’ );
}

$headers = wp_remote_retrieve_headers($response);
$binary_key = hex2bin(‘YOUR_DECRYPTION_KEY’);
$iv = base64_decode($headers[‘x-crypto-iv’]);
$tag = base64_decode($headers[‘x-crypto-tag’]);

$decrypted_pdf = openssl_decrypt(
wp_remote_retrieve_body($response),
‘aes-256-gcm’,
$binary_key,
OPENSSL_RAW_DATA,
$iv,
$tag
);
file_put_contents(‘submissions.pdf’, $decrypted_pdf);
`

How do I decrypt JSON payloads using PHP?

Parse the JSON response envelope and decrypt using OpenSSL:
php
$json = json_decode($response_body, true);
if (!empty($json['encrypted'])) {
$binary_key = hex2bin('YOUR_DECRYPTION_KEY');
$plaintext = openssl_decrypt(
base64_decode($json['ciphertext']),
$json['algorithm'],
$binary_key,
OPENSSL_RAW_DATA,
base64_decode($json['iv']),
base64_decode($json['tag'])
);
$data = json_decode($plaintext, true);
}

Does this plugin slow down my website?

No. Text feeds use lightweight JSON structures and binary feeds use raw stream transmission to ensure high throughput and low memory usage.

1.1.0

  • Added export format support for XLSX (Microsoft Excel), CSV, XML, and NDJSON/JSONL.
  • Added record limit support (?limit=N) for pagination and performance control.
  • Implemented real-time browser Web Crypto decryption preview for encrypted feeds.
  • Updated Setasign/FPDF library to version 1.9.0.
  • Enhanced security, superglobal unslashing, and full WP Plugin Check compliance.

1.0.1

Bugfix

1.0.0

Initial public release

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