Best API products of the month September 2026

VAT Engine

EU VAT calculation and compliance infrastructure for ecommerce and SaaS.

VAT Engine helps ecommerce businesses, SaaS teams, and developers calculate EU VAT, track OSS and IOSS exposure, and prepare reliable compliance reports. It combines VAT calculations, official rate data, transaction evidence, multi-store reporting, filing preparation, and developer-friendly APIs in one platform. Shopify integration is available, with support for additional ecommerce platforms planned. The goal is to make EU VAT workflows easier to understand, integrate, review, and hand over to accountants.

Eclatira

Conversational Video Agent That Plugs Into Any Stack

Plug real-time conversational video AI into any application with Eclatira. Developers get native voice-to-voice interaction, live vision, and full-stack execution across custom APIs, MCPs, and more than 3,000 apps. You can ship autonomous multimodal video agents quickly, without stitching together separate services. Eclatira handles the heavy lifting so your app can see, hear, and respond in real time.

Onepostly

The unified social media API for developers and AI agents

Onepostly provides a single, robust API to handle publishing, scheduling, analytics, and engagement across all major social media platforms. By abstracting away the complexity of platform-specific SDKs, OAuth, and token management, it allows developers and AI agents to ship cross-platform social features in minutes rather than weeks. Whether you are building an automation tool, a dashboard, or integrating social capabilities directly into your application, Onepostly ensures a consistent, stable, and normalized integration.

Static Forms

Form backend with spam protection, email delivery and AI replies

Static Forms is a form backend for developers and agencies. Connect an HTML form to collect submissions without building or maintaining a backend. Manage messages in an inbox and deliver them through email, webhooks and integrations including Google Sheets, Slack and Discord. Features include spam protection, file uploads, form rules, auto-responders and AI-powered replies. US and EU data residency options are available. Start with a free plan and upgrade for higher limits and additional features.

Get business summary from a URL

An API for URL-first onboarding

Let your users enter a URL instead of filling out a business form. An API for URL-first onboarding. Your user provides their website; we return structured business information you can use to prefill their submission, personalize onboarding, or configure your marketing tool.

StackScope

See what new sites are built with, the week they launch

StackScope lets you see which sites started using Stripe, Shopify, or Next.js this week. We find most of what we index ourselves, over 2.2 million sites from public infrastructure signals, across 40,000+ technologies. These sites are not submitted to us, and when we spot a launch before the boards, we are often 14.5 days early. Browsing is free. Paid plans add Stackdar alerts, API access, bulk export with published contact details, and an MCP server for Claude, ChatGPT, and Cursor.

OctoWatch DLP

Cloud or on-prem DLP for Windows teams that need proof.

OctoWatch DLP is a employee monitoring software with endpoint data loss prevention. It is for teams that need a usable record of work on company Windows PCs and a way to react when files, USB devices, or web activity cross policy lines. The product does not ship Mac or Linux agents. The Grabber agent installs on Windows workstations and on Windows Terminal Server / RDS sessions. Admins assign Settings, Rules, Timetable, and Computer profiles, then work in the Web Console. From there you can open Live view, review screenshots and video, and use Day viewer when you need a timeline of one day. The console also covers applications, websites, search queries, active and idle time, and timesheet-style reports. Depending on profile settings, capture may include keystrokes, email and IM, clipboard, prints, files and removable media, webcam and microphone, network traffic summaries, and web form posts

PAYGSEO is a suite of decision-based SEO tools built for AI agents (and yes, also humans). Validate keywords, uncover content opportunities, analyse competitors, check AI visibility, and decide what to improve next — with supporting evidence, a clear verdict, and recommended actions. Use the tools directly or connect them to ChatGPT, Claude, Cursor, and custom agents via MCP or REST. No subscription required: start with free credits and pay only for the SEO workflows you use.

DocsAlot

Documentation that works for both humans and AI systems

DocsAlot gathers your scattered help center articles, knowledge base entries, and developer docs into a single source of truth that works for both humans and AI agents. It includes hosted MCP, llms.txt, and skill.md, so your documentation is ready for modern AI workflows. With DocsAlot, your docs show up in AI answers, onboarding gets faster, and agents no longer waste time reading stale or outdated context.

Unsora AI

The creative toolkit your AI assistant can call from the chat you're already in

Unsora AI gives your AI assistant creative hands. Connect it once over MCP to ChatGPT, Claude, OpenClaw, or Hermes, and a full creative toolkit becomes something your assistant can call mid-conversation. Ask in plain language and get a finished file back. Cinematic video from a prompt and reference images. Ultra-realistic images. A recurring AI influencer who fronts your spots. Long streams cut into short captioned clips. Thumbnails from a prompt or a frame. Subtitles added, styled, or removed. Motion control that drives a still with camera moves from a reference clip. Upscaling to 4K for video and 8K for images. It runs leading models from Google, ByteDance, Kuaishou, and OpenAI, including Seedance 2.0, with new tools added often. When the file is ready, publish it without leaving the thread. Unsora pushes to TikTok, YouTube, X, Instagram, and more, or queues it for later. No editing experience needed, nothing to install. Every plan starts with a 3-day free trial.