Diff two branches the way a pull request would

GET/api/repos/{owner}/{repo}/compare

compareBranches

Returns the diff a pull request from `head` into `base` would contain: computed from the two branches' merge base rather than between their tips. Use this to preview a pull request before opening it. For a raw tree-to-tree diff between commit OIDs, use `/diff` instead. An unknown branch on either side, or a head already contained in the base, returns the empty diff rather than an error.

Authentication is not described for this operation in the spec — that does not mean it is public. Check tokens and scopes.

curl

curl -X GET 'https://neosource.dev/api/repos/OWNER/REPO/compare?base=BASE&head=HEAD'

fetch

fetch("https://neosource.dev/api/repos/OWNER/REPO/compare?base=BASE&head=HEAD", {
  method: "GET",
});

Path parameters

ownerrequired: Repository owner or organization slug.
string
reporequired: Repository name.
string

Query parameters

baserequired: Branch the change would merge INTO (the "before" side).
string
headrequired: Branch carrying the change (the "after" side).
string

Responses

200Diff result

application/json

DiffResponse

object

base_commitrequired

string

filesrequired

array

items

DiffFileResponse

object

additions: integer | null
Added lines in this file, or `null` when the file was never line-counted: it is binary, or one side exceeds the per-file byte ceiling. `null` and `0` mean different things and must not be conflated — `0` is "changed, but no lines changed" (an empty file added or deleted, a mode-only change), which is a fact about the file, while `null` is a fact about the diff. Uncounted files contribute nothing to `DiffStatsResponse`, so the per-file counts sum to the aggregate over exactly the counted ones.
deletions: integer | null
Removed lines in this file. See [`DiffFileResponse::additions`].
is_binaryrequired: boolean
new_oid: string | null
old_oid: string | null
patch: string | null
Unified diff text for this file. Omitted for binary files.
pathrequired: string
statusrequired: DiffFileStatus

head_commitrequired

string

statsrequired

DiffStatsResponse

object

additionsrequired: integer
deletionsrequired: integer
files_changedrequired: integer

truncatedrequired

boolean

`true` when the file list was capped by a response-size guard (total patch bytes or file count). `stats` still reflects the full diff; `files` carries only the retained prefix. Mirrors `BlobResponse.truncated` — honest truncation over a silent partial diff.

Standard errors

Bodies documented once for the whole API — see standard errors.

400Bad Request — one of: invalid_input
403Forbidden — one of: forbidden
404Not Found — one of: not_found
423Locked — one of: busy
429Rate limited — retry after the interval in the `Retry-After` header
500Internal server error
503Service temporarily unavailable / at capacity — retry after the `Retry-After` header
504Gateway timeout — the request exceeded the server's handling budget

Schemas

Referenced above. Listed here rather than expanded inline, so the same definition is not repeated at every level.

`DiffFileStatus`

string

"added""modified""deleted"