---
title: "Will this construct express?"
method: POST
path: "/expression_cassette_check"
tags: ["Enzymes & cloning"]
---

# Will this construct express?

`POST /expression_cassette_check`

## Request

- Base URL: `https://seqbench.com/api/v1`
- URL: `https://seqbench.com/api/v1/expression_cassette_check`
- Auth: none required

Check the ARRANGEMENT around each coding sequence, which is what decides whether a finished clone expresses at all: a promoter for the named host within reach on the same strand, a Shine-Dalgarno at a workable spacing (bacteria) or a Kozak context (eukaryote), every tag in the CDS's own reading frame, and a terminator or polyA signal downstream. Paste an annotated GenBank record and the CDS features are used; paste bare sequence and the long ORFs are found instead. Nothing here predicts a LEVEL — it reports what is present, absent or out of frame, and every absence names the signature library it was decided against rather than claiming the construct has none.

## Request body

- object
  - `sequence` string, required: The construct: a GenBank record (its CDS, promoter, terminator and tag features are used) or bare DNA.
  - `host` 'auto' | 'bacteria' | 'mammalian': Which host the cassette is for. `auto` infers it from the elements actually found (a CMV/polyA plasmid reads as mammalian, a T7/lac one as bacterial) and says in the result that it did.
  - `circular` boolean: Treat the construct as circular when annotating it.

## Response `200`

Tool ran successfully.

- SuccessResponse: Standard success envelope returned by every single-tool call.
  - `ok` unknown, required
  - `tool` string, required: The tool slug that ran.
  - `result` object, required: Tool-specific output object. Its shape depends on the tool — call `GET /{tool}` or see the docs for each tool's fields.
  - `gate` GateResult
    - `pass` boolean, required: True if and only if every hard check passed.
    - `checks` GateCheck[], required
      - `id` string, required
      - `label` string, required
      - `severity` 'hard' | 'soft', required
      - `pass` boolean, required
      - `message` string, required
      - `value` number
      - `threshold` string
    - `notChecked` string[], required: Honest list of what this gate does NOT verify.
  - `provenance` Provenance, required
    - `apiVersion` string, required
    - `tool` union, required: Tool slug, or an array of slugs (one per step) for a workflow.
      - string
      - string[]
    - `generatedAt` string, date-time, required: ISO 8601 timestamp of when the result was generated.

## Other responses

- `400`: Invalid argument or the tool could not run.
- `404`: Unknown tool.
- `429`: Rate limited (metered tools only). Body carries code `rate_limited` and retryable `true`; honor the Retry-After header.
- `503`: A metered tool is momentarily at capacity. The identical request should succeed after Retry-After; body carries code `upstream_unavailable`.

---

[API](https://skmtc.dev/seqbench/apis/seqbench-api.md) · [All operations](https://skmtc.dev/seqbench/apis/seqbench-api/llms.txt) · [OpenAPI document](https://skmtc.dev/seqbench/apis/seqbench-api/revisions/132575216865?raw)