---
title: Qiskit Fermions API documentation (latest version)
description: Index of all the modules in the latest version of qiskit-fermions-c.
source: https://quantum.cloud.ibm.com/docs/en/api/qiskit-fermions-c
---

# `qiskit-fermions` C API reference

This is the reference for the C API of the `qiskit-fermions` package.

## Operators

- [Operator Representations](/docs/api/qiskit-fermions-c/qf-operators)
- [Operator Library](/docs/api/qiskit-fermions-c/qf-operators-library)
- [Operator Terms](/docs/api/qiskit-fermions-c/qf-operators-terms)

## Mappers

- [Mapper Library](/docs/api/qiskit-fermions-c/qf-mappers-library)

## Miscellaneous

- [Various](/docs/api/qiskit-fermions-c/qf-various)


## Contents

- [API index](/docs/api/qiskit-fermions-c)
- [Release notes](/docs/api/qiskit-fermions/release-notes)
- [Commutator Generators](/docs/api/qiskit-fermions-c/qf-commutators)
- [Electronic Integrals](/docs/api/qiskit-fermions-c/qf-electronic-integrals)
- [FCIDump](/docs/api/qiskit-fermions-c/qf-fcidump)
- [Filtering Functions](/docs/api/qiskit-fermions-c/qf-operators-terms-filtering)
- [Grouping Functions](/docs/api/qiskit-fermions-c/qf-operators-terms-grouping)
- [Mapper Library](/docs/api/qiskit-fermions-c/qf-mappers-library)
- [Operator Library](/docs/api/qiskit-fermions-c/qf-operators-library)
- [Operator Representations](/docs/api/qiskit-fermions-c/qf-operators)
- [Operator Terms](/docs/api/qiskit-fermions-c/qf-operators-terms)
- [Ordering Functions](/docs/api/qiskit-fermions-c/qf-operators-terms-ordering)
- [QfExitCode](/docs/api/qiskit-fermions-c/qf-exit-code)
- [QfFermionOperator](/docs/api/qiskit-fermions-c/qf-ferm-op)
- [QfMajoranaOperator](/docs/api/qiskit-fermions-c/qf-maj-op)
- [Various](/docs/api/qiskit-fermions-c/qf-various)