---
title: "Get GrainBoundaryDoc documents"
method: GET
path: "/materials/grain_boundaries/"
tags: ["Materials Grain Boundaries"]
---

# Get GrainBoundaryDoc documents

`GET /materials/grain_boundaries/`

## Query parameters

- `material_ids` string, nullable — Comma-separated list of material_id values to query on
- `sigma_max` integer, nullable — Query for maximum value of sigma
- `sigma_min` integer, nullable — Query for minimum value of sigma
- `sigma` integer, nullable — Value of sigma.
- `sigma_not_eq` integer, nullable — Query for sigma being not equal to an exact value
- `sigma_eq_any` string — Query for sigma being any of these values. Provide a comma separated list.
- `sigma_neq_any` string — Query for sigma being not any of these values. Provide a comma separated list.
- `rotation_angle_max` number, nullable — Query for maximum value of rotation_angle
- `rotation_angle_min` number, nullable — Query for minimum value of rotation_angle
- `gb_energy_max` number, nullable — Query for maximum value of gb_energy
- `gb_energy_min` number, nullable — Query for minimum value of gb_energy
- `w_sep_max` number, nullable — Query for maximum value of w_sep
- `w_sep_min` number, nullable — Query for minimum value of w_sep
- `type` string, nullable — Grain boundary type.
- `chemsys` string, nullable — Dash-delimited string of elements in the material.
- `pretty_formula` string, nullable — Formula of the material.
- `gb_plane` string, nullable — Miller index of the grain boundary plane as comma delimitd integers.
- `rotation_axis` string, nullable — Miller index of the rotation axis as comma delimitd integers.
- `_page` integer — Page number to request (takes precedent over _limit and _skip).
- `_per_page` integer — Number of entries to show per page (takes precedent over _limit and _skip). Limited to 1000.
- `_skip` integer — Number of entries to skip in the search.
- `_limit` integer — Max number of entries to return in a single query. Limited to 1000.
- `_fields` string — Fields to project from GrainBoundaryDoc as a list of comma separated strings. Fields include: `material_id` `sigma` `type` `rotation_axis` `gb_plane` `rotation_angle` `gb_energy` `initial_structure` `final_structure` `pretty_formula` `w_sep` `structure` `chemsys` `last_updated`
- `_all_fields` boolean — Include all fields.
- `id_format` string, nullable — Optional. If set to 'legacy', MP identifier fields in the response are returned in the form 'mp-149'. If set to 'alpha', they are returned in the padded AlphaID form 'mp-aaaaaaft'. If omitted (or set to any other value), identifiers are returned in their stored form. This is a purely cosmetic transform; query inputs accept either shape regardless.

## Response `200`

Search for a GrainBoundaryDoc

- ResponseGrainBoundaryDoc
  - `data` GrainBoundaryDoc[], nullable — List of returned data
    - `material_id` unknown
    - `sigma` integer, nullable — Sigma value of the boundary.
    - `type` string, nullable — Grain boundary type.
    - `rotation_axis` integer[], nullable — Rotation axis.
    - `gb_plane` integer[], nullable — Grain boundary plane.
    - `rotation_angle` number, nullable — Rotation angle in degrees.
    - `gb_energy` number, nullable — Grain boundary energy in J/m^2.
    - `initial_structure` TypedGrainBoundaryDict — unresolved $ref
    - `final_structure` TypedGrainBoundaryDict — unresolved $ref
    - `pretty_formula` string, nullable — Reduced formula of the material.
    - `w_sep` number, nullable — Work of separation in J/m^2.
    - `structure` TypedStructureDict — unresolved $ref
    - `chemsys` string, nullable — Dash-delimited string of elements in the material.
    - `last_updated` string, date-time — Timestamp for the most recent calculation for this Material document.
  - `errors` Error[], nullable — Any errors on processing this query
    - `code` integer, required — The error code
    - `message` string, required — The description of the error
  - `meta` Meta — Meta information for the MAPI Response.
    - `api_version` string — A string containing the version of the Materials API implementation, e.g. v0.9.5
    - `time_stamp` string, date-time — A string containing the date and time at which the query was executed
    - `total_doc` integer, nullable — The total number of documents available for this query
    - `facet` object, nullable — A dictionary containing the facets available for this query

## Other responses

- `422` — Validation Error

## Changes

> 4 revisions in range; 1 could not be searched.

- **2026-07-31** `54f2f79ab4f8` — 1 info
  - the `api_version` response's property default value changed from `0.87.2.dev13+g62063a867` to `0.87.2.dev19+g3f2daf4f8` for the status `200`
- **2026-07-26** `9aac4fdf4081` — 1 info
  - the `api_version` response's property default value changed from `0.87.2.dev4+g6bd8ed856` to `0.87.2.dev13+g62063a867` for the status `200`

[Change history](https://skmtc.dev/materialsproject/apis/materials-project-api/changes/materials/grain_boundaries/get.md)

---

[API](https://skmtc.dev/materialsproject/apis/materials-project-api.md) · [All operations](https://skmtc.dev/materialsproject/apis/materials-project-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/materialsproject/materials-project-api/revisions/70f72d0670df/schema)