---
title: "Design new non-repetitive parts"
method: POST
path: "/nonrepetitive_parts_design"
tags: ["Enzymes & cloning"]
---

# Design new non-repetitive parts

`POST /nonrepetitive_parts_design`

## Request

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

Build a set of new genetic parts that match a degenerate (IUPAC) template and share more than a chosen length with nothing — not each other, not themselves, not a background sequence you supply. This is how a toolbox of promoters, RBSs, terminators or sgRNA handles is made large without making an assembly unstable. Honours a GC range and excluded motifs (restriction sites) during the search rather than filtering afterwards. Deterministic given a seed: the same inputs give the same toolbox. Returns fewer parts than asked, with a reason, when the constraints leave no room — it never invents a repetitive one to hit the count.

## Request body

- object
  - `constraint` string, required: The IUPAC template every part must match, e.g. "NNNNNNTTGACANNNNNNNNNNNNNNNNNTATAATNNNNNN" for a sigma-70 promoter library. N is any base; fixed letters are held. Max 1,000 nt.
  - `count` integer: How many parts to build (max 500).
  - `lmax` integer: Longest stretch any two parts may share, in bp (default 15).
  - `bothStrands` boolean: Treat a stretch and its reverse complement as the same stretch.
  - `gcMin` number: Lowest GC% a part may have.
  - `gcMax` number: Highest GC% a part may have.
  - `background` string[]: Sequences the new parts must also avoid sharing with — the host genome region, the vector, or a toolbox you already own.
  - `exclude` string[]: Motifs no part may contain, checked on both strands: restriction sites you clone with, a terminator you do not want. Literal ACGT only — an IUPAC code is refused rather than silently half-matched.
  - `seed` integer: Seeds the search. Change it for a different toolbox from the same constraints; keep it to reproduce one.

## 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)