About SDK.ac
Free browser-based prompt builders and opening-text extraction
Our Story
SDK.ac provides simple browser tools for preparing requests and extracting opening text. Seven tools assemble prompts using your input and fixed options. The eighth, Leading-Sentence Summarizer, selects the first punctuation-delimited chunks of a text without judging their importance.
You can inspect each result before using it. A prompt must be taken to a separate assistant to obtain a translation, email draft, code explanation, image, hashtag list, or revised passage. SDK.ac does not call a model or verify those external results.
All eight tool functions process inputs locally in the browser. The guides show exact outputs for specified inputs, explain the fixed templates, and identify limitations such as conflicting instructions or omitted sentences.
Our Mission
SDK.ac exists to make working with AI faster and less frustrating for people who write, code, translate, and publish for a living. We believe everyday AI utilities should be free, instant, mobile-friendly, and private by default. Whether you are drafting an email on a train, building an image prompt for a client mock-up, or trying to understand a block of unfamiliar code, you should get to a useful result in seconds — not after a signup flow.
We measure ourselves on three numbers: time-to-result (target: under three seconds from cold page load to usable output), clicks-to-result (target: as few as the task allows), and bytes of your text stored on our servers (target: zero). Every design decision on this site is downstream of those three numbers.
Long-term, the mission is bigger than the current catalogue. Prompting well is quickly becoming a basic literacy, like search queries were twenty years ago. We want SDK.ac to be the place a colleague recommends when you ask "is there a tool that helps with that?" — and we want you to feel zero regret when you click the link.
Who We Are
SDK.ac is operated by SDKLabs Co., Ltd., a Korean software company founded in 2025 that builds free online utilities and developer-focused tools. Our team has shipped consumer and developer web products used by millions of people, and we apply the same standards for UX, accuracy, and speed to every tool on this site.
Beyond SDK.ac, the same team operates SDK.is (developer utilities), JavaScript.ac (interactive JavaScript learning), SDK.bz (financial and crypto calculators), and SD.gy (everyday calculators). Lessons learned on one site — accessibility patterns, performance budgets, ad-density thresholds — get applied across all of them.
- Company
- SDKLabs Co., Ltd.
- Founded
- 2025
- Focus
- Prompt and text utilities, free web tools
- Business Registration
- 424-86-03401
- Address
- Suite 542, 60 Taebong-ro, Seocho-gu, Seoul, Republic of Korea
What You'll Find on SDK.ac
All eight tools are free and process inputs in your browser without an account. Seven assemble requests; one extracts opening text.
Translation Prompt Builder
Build a translation request from your text and selected languages. Does not translate it.
Leading-Sentence Summarizer
Extract the first punctuation-delimited chunks locally. No importance ranking or model is used.
Prompt Generator
Assemble a request from your task, optional context, and a fixed style instruction. No model is called.
Image Prompt Builder
Combine a subject with fixed style and mood phrases. Produces text, not an image.
Code Explanation Prompt Builder
Wrap code with its language label and a fixed explanation request. Does not run or analyze it.
Email Prompt Builder
Build an email drafting request from type, topic, recipient, and tone. Does not draft or send email.
Hashtag Prompt Builder
Build a hashtag request from topic, platform, and count. Does not fetch trends or generate tags.
Writing Revision Prompt Builder
Combine your text with a fixed revision instruction. Does not edit or correct the text itself.
Our Principles
Free Forever
No paywalls, no premium tier, no generation credits. Ads keep the tools free for everyone.
Your Text Stays Yours
Tool inputs are processed on your device. We never store, read, or train on what you type.
No Login, Ever
No account, no signup, no email capture. Open the page and start working.
Fast by Default
Sub-second loads on Cloudflare’s global edge network, on desktop and mobile alike.
Honest About AI
AI output can be wrong. We say so plainly, on every page where it matters.
No Dark Patterns
No fake countdowns, no "2 free uses left," no roach-motel cookie banners.
Technology Stack
Every piece of the stack was chosen to optimise load speed, reliability, and long-term maintainability for a small team.
The frontend is built with SvelteKit and TypeScript, styled with Tailwind CSS, and deployed to Cloudflare Pages. There is no traditional backend: pages are rendered at the edge, tool logic runs in your browser, and preferences (theme, language) live in your own localStorage. Where a tool produces a prompt for an external AI assistant, you carry that prompt to the assistant yourself — we never proxy your text through our infrastructure.
This architecture has practical consequences for you. First, time-to-interactive is measured in tens of milliseconds, not seconds. Second, there is no server database of user text that could leak, be subpoenaed, or be sold — because it does not exist. Third, our infrastructure costs are low enough that SDK.ac can stay free indefinitely without ever introducing a paid tier.
AI Limitations, Honestly
We build tools for working with AI, so we owe you plain talk about what AI cannot do. Large language models generate plausible text; they do not guarantee true text. They hallucinate facts, invent citations, mistranslate idioms, produce code that compiles but is subtly wrong, and write with total confidence in every one of those failure modes. A well-structured prompt — which is what our tools help you build — meaningfully improves output quality, but it does not eliminate these risks.
Our position is simple: AI output is a draft, not a deliverable. Verify translations with a native speaker before publishing. Run and test generated code before shipping it. Fact-check summaries against the source document when the stakes are real. Nothing produced with the help of SDK.ac constitutes professional, legal, medical, or financial advice, and the responsibility for reviewing and using AI output rests with you. We would rather say this clearly on our About page than bury it in a footnote.
How We Handle Your Text
Everything you type into a SDK.ac tool — text to summarize, code to explain, email points to draft — is processed on your device. It is not transmitted to our servers, not logged, not stored, and not used to train any model. When a tool generates a prompt for an external AI assistant, that prompt exists only in your browser until you choose to copy it and paste it somewhere else. What happens after you paste it into a third-party AI service is governed by that service's privacy policy, so choose your assistant accordingly for sensitive material.
The only data we collect is standard aggregated analytics (page views, country, device type) and the advertising cookies described in our Privacy Policy, which you can refuse. We never sell or share personal data. If our advertising provider changes its consent rules, we will update our consent handling immediately and note the change on the Privacy Policy page.
Contact Us
Have questions, suggestions, or feedback? We read every message.
- General questions and feedback: [email protected]
- Bug reports: please include the tool, your browser and OS, and steps to reproduce.
- Tool suggestions: tell us which AI task you wish had a one-button tool — real use cases move our roadmap.
- Business, partnership, and advertising: include "Business" in your subject line.
- Privacy requests and legal notices: include "Legal" in your subject line.
Legal & Operator Information
SDK.ac is operated by SDKLabs Co., Ltd., a Korean corporation registered with the competent authorities of the Republic of Korea (business registration 424-86-03401).