Debug HTTP without leaving the shell.

sonde sends, records, replays and diffs API requests as plain files on disk. One static binary. No GUI, no cloud sync, no account — just your prompt.

sonde — zsh ~/api 96×28

~/api $ sonde get api.helios.dev/v2/launches --env staging -v
  dns 4ms · tls 21ms · ttfb 118ms · total 143ms
  HTTP/2 200 · application/json · 3.2 KB
  { "count": 3, "results": [ { "id": "lx_9021", "vehicle": "Antares 330", "window_open": "2026-08-11T09:40:00Z" }, … ] }

~/api $ sonde save launches-baseline
  saved -> .sonde/runs/launches-baseline  (request + response, 2 files)

~/api $ sonde get api.helios.dev/v2/launches --env staging --diff launches-baseline
  HTTP/2 200 · 121ms · compared against launches-baseline
  ~ results[0].window_open   "…T09:40:00Z" -> "…T11:05:00Z"
  + results[0].hold_reason   "range weather"
  2 changes · headers identical

~/api $

# macOS / Linux — one static binary $ curl -fsSL https://get.sonde.sh | sh

# or via Homebrew $ brew install sonde-sh/tap/sonde

##Flags

The whole surface fits on one screen; every flag has a config-file twin in .sonde/config.toml.

flag	arg	default	what it does
-H, --header	key: value	—	Attach a request header. Repeatable; `$VARS` expand from the environment.
--env	name	—	Load host, headers and secrets from `.sonde/<name>.toml`.
--save	name	—	Record request and response as plain text files under `.sonde/runs/`.
--diff	ref	last	Compare the response against a saved run; print a structural diff.
--replay	ref	last	Re-send a recorded request byte-for-byte, headers included.
-o, --output	mode	auto	`auto`, `json`, `headers`, `raw`, or `silent` for scripting.
--timeout	dur	30s	Abort after a duration: `500ms`, `10s`, `2m`.
-v, --verbose		off	Print DNS, TLS, redirect and timing phases for each request.

Full reference: sonde --help · man sonde(1)

##Runs are files

Plain text, on disk: Requests and responses land as readable text under .sonde/. Grep them, commit them, code-review an API change like code.
One binary, anywhere: No runtime, no plugin directory, no background updater. Works the same in ~/bin or on the far side of an ssh session.
Diff over pretty-print: The interesting question is rarely “what did it return” — it is “what changed since Tuesday”. One flag answers it.

.sonde/
|-- config.toml
|-- staging.toml      # --env staging
`-- runs/
    `-- launches-baseline/
        |-- request.http
        `-- response.json  # no database