---
title: "Get EOSDoc documents"
method: GET
path: "/materials/eos/"
tags: ["Materials EOS"]
---

# Get EOSDoc documents

`GET /materials/eos/`

## Query parameters

- `task_ids` string, nullable — Comma-separated list of task_ids to query on
- `_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 EOSDoc as a list of comma separated strings. Fields include: `task_id` `energies` `volumes` `eos`
- `_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 EOSDoc

- ResponseEOSDoc
  - `data` EOSDoc[], nullable — List of returned data
    - `task_id` unknown
    - `energies` number[], nullable — Energies in eV that the equations of state are plotted with.
    - `volumes` number[], nullable — Volumes in A³ that the equations of state are plotted with.
    - `eos` EOSFit[], nullable — Data for each type of equation of state.
      - `model` string, required — The EOS model used to fit the data.
      - `V0` number, nullable — The equilibrium volume in ų.
      - `B0` number, nullable — The equilibrium bulk modulus, in GPa.
      - `B1` number, nullable — The pressure derivative of the bulk modulus at V0, dimensionless.
      - `E0` number, nullable — The equilibrium energy, in eV.
      - `R2` number, nullable — The fit R2 (coefficient of determination), dimensionless.
  - `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

- **2026-08-20** `70f72d0670df` — 2 info
  - added the new optional `query` request parameter `id_format`
  - the `api_version` response's property default value changed from `0.87.2.dev19+g3f2daf4f8` to `0.87.3.dev3+gfbe8656b6` for the status `200`
- **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/eos/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)