<div class="screenshot">
<img src="/img/tutorial/request-form-models/image01.png">
</div>

## Forbid Extra Form Fields { #forbid-extra-form-fields }

In some special use cases (probably not very common), you might want to **restrict** the form fields to only those declared in the Pydantic model. And **forbid** any **extra** fields.

/// note

This is supported since FastAPI version `0.114.0`. 🤓

///

import com.google.common.base.Equivalence;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.base.Ticker;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.BiMap;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.HashBiMap;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.HashMultiset;

import com.google.common.base.Splitter;
import com.google.common.base.Stopwatch;
import com.google.common.base.Ticker;
import com.google.common.collect.BiMap;
import com.google.common.collect.ClassToInstanceMap;
import com.google.common.collect.ImmutableBiMap;
import com.google.common.collect.ImmutableClassToInstanceMap;
import com.google.common.collect.ImmutableCollection;
import com.google.common.collect.ImmutableList;

import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.AbstractCollectionTester;
import com.google.common.collect.testing.features.CollectionFeature;

 */

package configurations

import common.INDIVIDUAL_PERFORAMCE_TEST_ARTIFACT_RULES
import common.KillProcessMode.KILL_ALL_GRADLE_PROCESSES
import common.KillProcessMode.KILL_PROCESSES_STARTED_BY_GRADLE
import common.Os
import common.applyPerformanceTestSettings
import common.buildScanTagParam
import common.buildToolGradleParameters
import common.checkCleanM2AndAndroidUserHome
import common.getBuildScanCustomValueParam

 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.Helpers.getMethod;
import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multimap;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.MapFeature;
import org.junit.Ignore;

/**
 * Tester for {@code Multimap.toString()}.
 *

 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION;
import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_REMOVE;
import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;

import static com.google.common.math.StatsTesting.LONG_MANY_VALUES_MIN;
import static com.google.common.math.StatsTesting.LONG_MANY_VALUES_SUM_OF_SQUARES_OF_DELTAS;
import static com.google.common.math.StatsTesting.MANY_VALUES;
import static com.google.common.math.StatsTesting.MANY_VALUES_COUNT;
import static com.google.common.math.StatsTesting.MANY_VALUES_MAX;
import static com.google.common.math.StatsTesting.MANY_VALUES_MEAN;

The most common is the implicit flow.

The most secure is the code flow, but it's more complex to implement as it requires more steps. As it is more complex, many providers end up suggesting the implicit flow.

/// note

It's common that each authentication provider names their flows in a different way, to make it part of their brand.