Which Tool Do I Need

BitSpeed is two separate tools that happen to share a home. They don’t depend on each other, and most people only need one. Start from the problem you have.

Something got slow and you want to know where

Use Inspect. It records HTTP requests to a URL, splits each one into measured intervals (DNS, connecting, TLS, waiting for the first byte, reading the body) and tells you which interval took the time. Save a recording before a change and another after, and compare tells you what moved and whether the samples are good enough to say so.

bitspeed-inspect record https://example.com/ > before.json
bitspeed-inspect explain before.json
# deploy, then
bitspeed-inspect record https://example.com/ > after.json
bitspeed-inspect compare before.json after.json

Pick Inspect if any of these sound familiar: a page or API feels slower since last week, you want a CI job to fail when a request gets slower, you want to know what keep-alive saves, or curl’s timing numbers leave you guessing. It runs only from the client side, so it shows where the wait happened, never why the server took that long. The Inspect guide has the details.

Use Transfer. It snapshots one file, sends it in verified chunks and, after a crash, a kill or a dropped connection, asks the receiver what it can prove and sends only the rest. The finished file is checked against its full SHA-256 before it’s published, and it never replaces a file that’s already there.

bitspeed-transfer serve --root=receiver --token-file=token
bitspeed-transfer send --prepare-only --source=big-file.iso --spool=sender
bitspeed-transfer send --spool=sender --reuse=TRANSFER_ID --url=http://127.0.0.1:8080 --token-file=token

Pick Transfer if you move one large file at a time over links that drop, between Linux, macOS and Windows machines, and you need to know that what arrived is exactly what left. It isn’t a sync tool: no folders, no deltas, no parallel streams. For those, rsync and rclone are better fits, as this comparison explains. The Transfer guide covers setup.

Both at once

They do fit together. If a large download from your own server is slow, Inspect tells you whether the time goes into the connection, the first-byte wait or the body. If the trouble is that big uploads keep dying halfway, that’s Transfer’s job. Each has its own download, version and release notes, and you can install either without the other.

Get them from the download page, or try the quick start.