400

Do not retry

Malformed request — Something in the request itself is wrong — most often a cursor.

Response body

{ "error": { "code": "invalid_cursor", … } }

Should you retry?

No — the same request will fail the same way. Fix it first.

What it means

The server understood the request and rejected it. Retrying the same request produces the same result. error.code says which case you hit — invalid_cursor, missing_parameter, invalid_request or batch_too_large.

Common causes

`invalid_cursor` — a `cursor` value that was edited, truncated or built by hand.
`missing_parameter` — a required parameter was not sent.
`invalid_request` — most often a query parameter the endpoint does not accept: a typo, an invented filter, or a spelling retired in an earlier release. `details.parameters` names each one and `details.supported` lists what the endpoint does take. Also covers a request that could not be parsed.
`batch_too_large` — too many operations in one MCP JSON-RPC batch.

How to fix it

Fix the request. For a cursor error, restart pagination without the bad cursor — cursors are opaque and must be passed back exactly as received, never constructed.

Endpoints that return this

Read from the OpenAPI specification, so this list cannot claim an endpoint returns a status the contract does not list.

Method	Endpoint	What it does
GET	/v4/jobs	Search jobs
POST	/mcp	MCP server (JSON-RPC 2.0)
GET	/v4/signals	List signals
GET	/v4/sources-id/{source_id}/signals	One employer's signals
GET	/v4/metrics	Metrics for a slice
POST	/v4/metrics/query	Metrics for a slice (POST)
GET	/v4/metrics/series	Metrics over time
GET	/v4/metrics/distribution	Pay distribution for a slice
GET	/v4/metrics/concentration	Where this work is concentrated
GET	/v4/metrics/benchmark	A slice against a wider one
GET	/v4/metrics/skill-premium	What each technology pays in a slice
GET	/v4/technologies	Search the technology catalog
GET	/v4/technologies/trend	Technologies over time in a slice
GET	/v4/technologies/stack	A slice's stack
GET	/v4/technologies/churn	How fast a slice's skill mix turns over
GET	/v4/technologies/bridge	Where two occupations converge
GET	/v4/technologies/similar-occupations	Occupations with a similar skill mix

400