toolun has more than two hundred tools, but nobody opens it thinking “I want to use PDF Merge” — they think “I need to send this contract to the other side, so it has to be merged, page-numbered, watermarked and given a password”. Find a tool by task lists that kind of single job — 37 of them, covering office documents, images, audio and video, development and everyday life — gives each one a one-line goal, and then lays out 3–4 steps, every step linking to a concrete tool on this site and saying which parameters to choose and where the traps are.

Two things it is not. It is not an outbound link directory, because every step happens inside toolun, so each one is “click and do it”. And it is not a tool manual: each tool page documents itself, and this page only says what the tool is responsible for inside this chain and how to set it. The “I have a file…” control at the top filters by file type: if you are holding a pile of HEIC files, you only see tasks that can start from HEIC; with no file at all, you see the “from scratch” tasks.

The list grew out of a product audit of searches that returned nothing: “image is too big to send”, “how do I turn a scan into a searchable PDF”, “video is too big for WeChat” — questions that no tool name can match, and exactly what this page exists to catch.

1. 01Say what you want to do— type the goal or the file type into the search box (“contract”, “ID photo”, “WeChat 25MB”, “3x3 grid”); titles, goals, step notes and tags are all matched.
2. 02Or start from the file— under “I have a file…”, click PDF / image / HEIC / video / Word / Excel / text / JSON / archive to see only the tasks that take it as input; “No file” shows the generate-from-scratch tasks.
3. 03Read the steps— each step is “tool name + what this step does + parameter advice”; a yellow box holds the warnings (what cannot be undone, what carries legal weight).
4. 04Do the work— click a tool name inside a step to open it, or click “Start from step 1”; download the result after each step, then upload it in the next one.
5. 05Bookmark— star a task you do often to pin it to the top of the page (stored on this device).

One of the tasks shown after picking “HEIC (iPhone photos)”:

Searching “contract”:

Images › A batch of HEIC → JPG → uniform size → long image
Goal: turn a set of iPhone photos into one long image you can post to WeChat Moments / Xiaohongshu.
  1  Image Converter    HEIC to JPG in bulk     quality around 85 balances size and looks
  2  Resize Images      uniform width           scale to "width 1080", height automatic
  3  Long Image Stitch  vertical join           spacing and background colour optional
  4  Image Compress     fit the platform limit  Xiaohongshu caps one image at 20 MB, WeChat long images are best under 5 MB
Note: when a long image gets very tall some platforms blur it, so split into two beyond 20 photos

Office documents › Contract: merge → page numbers → watermark → encrypt
  Word to PDF → PDF Merge → PDF Page Numbers → PDF Watermark → PDF Protect
Office documents › Scanned pages → searchable PDF
  Image Converter → Scan Enhance → Image to PDF → PDF OCR
Office documents › Sign a PDF and flatten it
  Handwritten Signature → PDF Sign → PDF Flatten

Why organise by task rather than by tool

The default shape of a tool site is a catalogue: every tool listed by category, and the user assembles the flow. That works for someone who knows the tool's name, and fails three other kinds of visitor — the one holding a file and unsure which tool fits, the one who knows the job but calls it something else (“remove the background” = cutout, “Apple photos” = HEIC), and the one whose job spans two or three tools. The audit found that searches from all three groups came back empty almost every time. A task page makes the job the entry point: every task is a fixed sequence of tools, and the user needs to know no tool names and to work out no order.

How the order inside a chain is decided

The principle is cut losses first, then process, then shrink. Take “scanned pages → searchable PDF”: convert the format first (many downstream tools cannot read HEIC), then enhance the image (deskewing and shadow removal raise OCR accuracy noticeably, so enhancement has to come before OCR), then assemble the PDF (running OCR over one PDF in a single pass is less work than image by image), and run OCR last. Compression always sits at the very end — it is lossy, and further processing after it magnifies the loss; encryption also comes last, because most tools cannot open an encrypted file. In the signing chain, “flatten” follows the signature, because flattening freezes editable objects into page content that can no longer be changed.

Irreversible steps get their own warning

A yellow box flags three kinds of thing: irreversible (redaction, flattening, compression) — keep the original before you run them; legally loaded (an image signature is not the same as a certificate-based digital signature, and an official ID photo has to be taken at a designated studio); and platform rules (WeChat 25 MB, Xiaohongshu (RedNote) 20 MB, a 200 KB application portal) — these are why the task exists, and they decide the parameters of the last step.

Where the parameter advice comes from

The advice on each step is the value that has proved most reliable in that chain, not the only correct one: JPEG quality 85 is the usual turning point between size and looks; a long image 1080 px wide matches the CSS pixel density of mainstream phones; 720p at 1.5 Mbps is the combination that fits two minutes inside 25 MB; a watermark opacity of 15–25% stays visible without covering the body text. Every number can be adjusted on the individual tool page, whose notes explain the reasoning in more detail.

How this relates to flow pages and search

This page is the master index of tasks; each task will later get a flow page of its own (/guide/<slug>) carrying a longer background and screenshots, and a task's id here is the slug of that future page. The task chips in the site-wide search will link to the matching anchor here (#task-<id>), so whichever entrance you come through you land on the same chain.

Inclusion criteria

tasks that keep recurring in audits and search logs and that can be completed end to end inside toolun; every chain has 2–5 steps, and each tool a step points at has to exist (an automated test enforces it).

What is excluded

tasks that need an outside service to finish (a cloud OCR account as a mandatory step, for example), steps for which this site has no tool yet (burning in subtitles is still experimental and stays out of the chains), and single-tool operations (that is the tool page's own business).

File hand-off

at this stage every step still needs a download and a fresh upload; nothing goes to a server, but the file does pass through your download folder.

Parameters are advice

they are chosen for common cases, and platform rules change (the limits of WeChat and Xiaohongshu follow their own documentation at the time).

Legal notes

the remarks on the effect of image signatures, redaction and ID photos are plain-language reminders, not legal advice.

This page is navigation only: the task data loads statically with the page, and search, filtering and bookmarks happen locally in the browser without sending a request. Every tool it links to processes files in the browser (the few marked API call a third-party interface and say so), intermediate results sit in your download folder, and this site's servers never receive a file.

• toolun tool directory（访问日期：2026-09-09） — every tool a step points at can be found in the categories on the home page.
• WeChat Help Center（访问日期：2026-09-09） — the size and length limits for file transfer and Moments video follow the official documentation.
• An introduction to the PDF file structure (an on-site guide, not published yet) — why merging drops bookmarks, and what flattening actually does.