Issue:
Bug: Add Fiserv for card payments





Pull request description:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [x] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates

## Description
Authorize and capture flow
Todo: Issue for optimising the encoding process in header and body #370 

### Additional Changes

- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

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Following are the paths where you can find config files:
1. `config`
2. `crates/router/src/configs`
3. `loadtest/config`
-->


## Motivation and Context
Adding a new connector `Fiserv`
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Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.

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Closes #229.

## How did you test it?
Added unit tests for mentioned payment flows.

<img width="784" alt="Screenshot 2023-01-13 at 7 43 38 PM" src="https://user-images.githubusercontent.com/55536657/212340057-35e12934-a1a8-4ca6-b411-729d27d6e357.png">

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Did you write an integration/unit/API test to verify the code changes?
Or did you test this change manually (provide relevant screenshots)?
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## Checklist
<!-- Put an `x` in the boxes that apply -->

- [x] I formatted the code `cargo +nightly fmt`
- [x] I addressed lints thrown by `cargo clippy`
- [x] I reviewed submitted code
- [ ] I added unit tests for my changes where possible
- [ ] I added a [CHANGELOG](/CHANGELOG.md) entry if applicable


Testing:
Added unit tests for mentioned payment flows.

<img width="784" alt="Screenshot 2023-01-13 at 7 43 38 PM" src="https://user-images.githubusercontent.com/55536657/212340057-35e12934-a1a8-4ca6-b411-729d27d6e357.png">



Patch:
diff --git a/config/Development.toml b/config/Development.toml
index 06b4d544c0a..fa61e28810c 100644
--- a/config/Development.toml
+++ b/config/Development.toml
@@ -43,7 +43,7 @@ locker_decryption_key2 = ""
 
 [connectors.supported]
 wallets = ["klarna","braintree","applepay"]
-cards = ["stripe","adyen","authorizedotnet","checkout","braintree","aci","shift4","cybersource", "worldpay", "globalpay"]
+cards = ["stripe","adyen","authorizedotnet","checkout","braintree","aci","shift4","cybersource", "worldpay", "globalpay", "fiserv"]
 
 [refund]
 max_attempts = 10
@@ -82,6 +82,9 @@ base_url = "https://apitest.cybersource.com/"
 [connectors.shift4]
 base_url = "https://api.shift4.com/"
 
+[connectors.fiserv]
+base_url = "https://cert.api.fiservapps.com/"
+
 [connectors.worldpay]
 base_url = "http://localhost:9090/"
 
diff --git a/config/config.example.toml b/config/config.example.toml
index cabc652c91e..6bedd98ab23 100644
--- a/config/config.example.toml
+++ b/config/config.example.toml
@@ -133,6 +133,9 @@ base_url = "https://apitest.cybersource.com/"
 [connectors.shift4]
 base_url = "https://api.shift4.com/"
 
+[connectors.fiserv]
+base_url = "https://cert.api.fiservapps.com/"
+
 [connectors.worldpay]
 base_url = "https://try.access.worldpay.com/"
 
diff --git a/config/docker_compose.toml b/config/docker_compose.toml
index 0c026939849..d38380b73c8 100644
--- a/config/docker_compose.toml
+++ b/config/docker_compose.toml
@@ -85,6 +85,9 @@ base_url = "https://apitest.cybersource.com/"
 [connectors.shift4]
 base_url = "https://api.shift4.com/"
 
+[connectors.fiserv]
+base_url = "https://cert.api.fiservapps.com/"
+
 [connectors.worldpay]
 base_url = "https://try.access.worldpay.com/"
 
@@ -93,4 +96,4 @@ base_url = "https://apis.sandbox.globalpay.com/ucp/"
 
 [connectors.supported]
 wallets = ["klarna", "braintree", "applepay"]
-cards = ["stripe", "adyen", "authorizedotnet", "checkout", "braintree", "shift4", "cybersource", "worldpay", "globalpay"]
+cards = ["stripe", "adyen", "authorizedotnet", "checkout", "braintree", "shift4", "cybersource", "worldpay", "globalpay", "fiserv"]
diff --git a/crates/api_models/src/enums.rs b/crates/api_models/src/enums.rs
index cdb2f70d1fe..83ead25c354 100644
--- a/crates/api_models/src/enums.rs
+++ b/crates/api_models/src/enums.rs
@@ -503,6 +503,7 @@ pub enum Connector {
     Cybersource,
     #[default]
     Dummy,
+    Fiserv,
     Globalpay,
     Klarna,
     Payu,
diff --git a/crates/common_utils/src/lib.rs b/crates/common_utils/src/lib.rs
index 8ba8aa195a5..fd730414808 100644
--- a/crates/common_utils/src/lib.rs
+++ b/crates/common_utils/src/lib.rs
@@ -27,6 +27,11 @@ pub mod date_time {
     pub fn convert_to_pdt(offset_time: OffsetDateTime) -> PrimitiveDateTime {
         PrimitiveDateTime::new(offset_time.date(), offset_time.time())
     }
+
+    /// Return the UNIX timestamp of the current date and time in UTC
+    pub fn now_unix_timestamp() -> i64 {
+        OffsetDateTime::now_utc().unix_timestamp()
+    }
 }
 
 /// Generate a nanoid with the given prefix and length
diff --git a/crates/router/src/configs/defaults.toml b/crates/router/src/configs/defaults.toml
index fe24060d3c6..5e447f2775d 100644
--- a/crates/router/src/configs/defaults.toml
+++ b/crates/router/src/configs/defaults.toml
@@ -63,4 +63,4 @@ max_read_count = 100
 
 [connectors.supported]
 wallets = ["klarna","braintree"]
-cards = ["stripe","adyen","authorizedotnet","checkout","braintree", "cybersource"]
+cards = ["stripe","adyen","authorizedotnet","checkout","braintree", "cybersource", "fiserv"]
diff --git a/crates/router/src/configs/settings.rs b/crates/router/src/configs/settings.rs
index 0707dfb1dbf..3aeb0fc0410 100644
--- a/crates/router/src/configs/settings.rs
+++ b/crates/router/src/configs/settings.rs
@@ -127,6 +127,7 @@ pub struct Connectors {
     pub braintree: ConnectorParams,
     pub checkout: ConnectorParams,
     pub cybersource: ConnectorParams,
+    pub fiserv: ConnectorParams,
     pub globalpay: ConnectorParams,
     pub klarna: ConnectorParams,
     pub payu: ConnectorParams,
diff --git a/crates/router/src/connector.rs b/crates/router/src/connector.rs
index a790601e5e4..2b9ef18559f 100644
--- a/crates/router/src/connector.rs
+++ b/crates/router/src/connector.rs
@@ -5,6 +5,7 @@ pub mod authorizedotnet;
 pub mod braintree;
 pub mod checkout;
 pub mod cybersource;
+pub mod fiserv;
 pub mod globalpay;
 pub mod klarna;
 pub mod payu;
@@ -15,6 +16,7 @@ pub mod worldpay;
 
 pub use self::{
     aci::Aci, adyen::Adyen, applepay::Applepay, authorizedotnet::Authorizedotnet,
-    braintree::Braintree, checkout::Checkout, cybersource::Cybersource, globalpay::Globalpay,
-    klarna::Klarna, payu::Payu, shift4::Shift4, stripe::Stripe, worldpay::Worldpay,
+    braintree::Braintree, checkout::Checkout, cybersource::Cybersource, fiserv::Fiserv,
+    globalpay::Globalpay, klarna::Klarna, payu::Payu, shift4::Shift4, stripe::Stripe,
+    worldpay::Worldpay,
 };
diff --git a/crates/router/src/connector/fiserv.rs b/crates/router/src/connector/fiserv.rs
new file mode 100644
index 00000000000..b4b78f84168
--- /dev/null
+++ b/crates/router/src/connector/fiserv.rs
@@ -0,0 +1,426 @@
+mod transformers;
+
+use std::fmt::Debug;
+
+use base64::Engine;
+use bytes::Bytes;
+use error_stack::ResultExt;
+use ring::hmac;
+use time::OffsetDateTime;
+use transformers as fiserv;
+use uuid::Uuid;
+
+use crate::{
+    configs::settings,
+    consts,
+    core::{
+        errors::{self, CustomResult},
+        payments,
+    },
+    headers, services,
+    types::{
+        self,
+        api::{self},
+    },
+    utils::{self, BytesExt},
+};
+
+#[derive(Debug, Clone)]
+pub struct Fiserv;
+
+impl Fiserv {
+    pub fn generate_authorization_signature(
+        &self,
+        auth: fiserv::FiservAuthType,
+        request_id: &str,
+        payload: &str,
+        timestamp: i128,
+    ) -> CustomResult<String, errors::ConnectorError> {
+        let fiserv::FiservAuthType {
+            api_key,
+            api_secret,
+            ..
+        } = auth;
+        let raw_signature = format!("{api_key}{request_id}{timestamp}{payload}");
+
+        let key = hmac::Key::new(hmac::HMAC_SHA256, api_secret.as_bytes());
+        let signature_value =
+            consts::BASE64_ENGINE.encode(hmac::sign(&key, raw_signature.as_bytes()).as_ref());
+        Ok(signature_value)
+    }
+}
+
+impl api::ConnectorCommon for Fiserv {
+    fn id(&self) -> &'static str {
+        "fiserv"
+    }
+
+    fn common_get_content_type(&self) -> &'static str {
+        "application/json"
+    }
+
+    fn base_url<'a>(&self, connectors: &'a settings::Connectors) -> &'a str {
+        connectors.fiserv.base_url.as_ref()
+    }
+}
+
+impl api::Payment for Fiserv {}
+
+impl api::PreVerify for Fiserv {}
+
+#[allow(dead_code)]
+impl
+    services::ConnectorIntegration<
+        api::Verify,
+        types::VerifyRequestData,
+        types::PaymentsResponseData,
+    > for Fiserv
+{
+}
+
+impl api::PaymentVoid for Fiserv {}
+
+#[allow(dead_code)]
+impl
+    services::ConnectorIntegration<
+        api::Void,
+        types::PaymentsCancelData,
+        types::PaymentsResponseData,
+    > for Fiserv
+{
+}
+
+impl api::PaymentSync for Fiserv {}
+
+#[allow(dead_code)]
+impl
+    services::ConnectorIntegration<api::PSync, types::PaymentsSyncData, types::PaymentsResponseData>
+    for Fiserv
+{
+}
+
+impl api::PaymentCapture for Fiserv {}
+impl
+    services::ConnectorIntegration<
+        api::Capture,
+        types::PaymentsCaptureData,
+        types::PaymentsResponseData,
+    > for Fiserv
+{
+    fn get_headers(
+        &self,
+        req: &types::PaymentsCaptureRouterData,
+        _connectors: &settings::Connectors,
+    ) -> CustomResult<Vec<(String, String)>, errors::ConnectorError> {
+        let timestamp = OffsetDateTime::now_utc().unix_timestamp_nanos() / 1_000_000;
+        let auth: fiserv::FiservAuthType =
+            fiserv::FiservAuthType::try_from(&req.connector_auth_type)?;
+        let api_key = auth.api_key.clone();
+
+        let fiserv_req = self
+            .get_request_body(req)?
+            .ok_or(errors::ConnectorError::RequestEncodingFailed)?;
+        let client_request_id = Uuid::new_v4().to_string();
+        let hmac = self
+            .generate_authorization_signature(auth, &client_request_id, &fiserv_req, timestamp)
+            .change_context(errors::ConnectorError::RequestEncodingFailed)?;
+        let headers = vec![
+            (
+                headers::CONTENT_TYPE.to_string(),
+                types::PaymentsAuthorizeType::get_content_type(self).to_string(),
+            ),
+            ("Client-Request-Id".to_string(), client_request_id),
+            ("Auth-Token-Type".to_string(), "HMAC".to_string()),
+            ("Api-Key".to_string(), api_key),
+            ("Timestamp".to_string(), timestamp.to_string()),
+            ("Authorization".to_string(), hmac),
+        ];
+        Ok(headers)
+    }
+
+    fn get_content_type(&self) -> &'static str {
+        "application/json"
+    }
+
+    fn get_request_body(
+        &self,
+        req: &types::PaymentsCaptureRouterData,
+    ) -> CustomResult<Option<String>, errors::ConnectorError> {
+        let fiserv_req = utils::Encode::<fiserv::FiservCaptureRequest>::convert_and_encode(req)
+            .change_context(errors::ConnectorError::RequestEncodingFailed)?;
+        Ok(Some(fiserv_req))
+    }
+
+    fn build_request(
+        &self,
+        req: &types::PaymentsCaptureRouterData,
+        connectors: &settings::Connectors,
+    ) -> CustomResult<Option<services::Request>, errors::ConnectorError> {
+        let request = Some(
+            services::RequestBuilder::new()
+                .method(services::Method::Post)
+                .url(&types::PaymentsCaptureType::get_url(self, req, connectors)?)
+                .headers(types::PaymentsCaptureType::get_headers(
+                    self, req, connectors,
+                )?)
+                .body(types::PaymentsCaptureType::get_request_body(self, req)?)
+                .build(),
+        );
+        Ok(request)
+    }
+
+    fn handle_response(
+        &self,
+        data: &types::PaymentsCaptureRouterData,
+        res: types::Response,
+    ) -> CustomResult<types::PaymentsCaptureRouterData, errors::ConnectorError> {
+        let response: fiserv::FiservPaymentsResponse = res
+            .response
+            .parse_struct("Fiserv Payment Response")
+            .change_context(errors::ConnectorError::ResponseDeserializationFailed)?;
+        types::ResponseRouterData {
+            response,
+            data: data.clone(),
+            http_code: res.status_code,
+        }
+        .try_into()
+        .change_context(errors::ConnectorError::ResponseHandlingFailed)
+    }
+
+    fn get_url(
+        &self,
+        _req: &types::PaymentsCaptureRouterData,
+        connectors: &settings::Connectors,
+    ) -> CustomResult<String, errors::ConnectorError> {
+        Ok(format!(
+            "{}ch/payments/v1/charges",
+            connectors.fiserv.base_url
+        ))
+    }
+
+    fn get_error_response(
+        &self,
+        res: Bytes,
+    ) -> CustomResult<types::ErrorResponse, errors::ConnectorError> {
+        let response: fiserv::ErrorResponse = res
+            .parse_struct("Fiserv ErrorResponse")
+            .change_context(errors::ConnectorError::ResponseDeserializationFailed)?;
+
+        let fiserv::ErrorResponse { error, details } = response;
+
+        let message = match (error, details) {
+            (Some(err), _) => err
+                .iter()
+                .map(|v| v.message.clone())
+                .collect::<Vec<String>>()
+                .join(""),
+            (None, Some(err_details)) => err_details
+                .iter()
+                .map(|v| v.message.clone())
+                .collect::<Vec<String>>()
+                .join(""),
+            (None, None) => consts::NO_ERROR_MESSAGE.to_string(),
+        };
+
+        Ok(types::ErrorResponse {
+            code: consts::NO_ERROR_CODE.to_string(),
+            message,
+            reason: None,
+        })
+    }
+}
+
+impl api::PaymentSession for Fiserv {}
+
+#[allow(dead_code)]
+impl
+    services::ConnectorIntegration<
+        api::Session,
+        types::PaymentsSessionData,
+        types::PaymentsResponseData,
+    > for Fiserv
+{
+}
+
+impl api::PaymentAuthorize for Fiserv {}
+
+impl
+    services::ConnectorIntegration<
+        api::Authorize,
+        types::PaymentsAuthorizeData,
+        types::PaymentsResponseData,
+    > for Fiserv
+{
+    fn get_headers(
+        &self,
+        req: &types::PaymentsAuthorizeRouterData,
+        _connectors: &settings::Connectors,
+    ) -> CustomResult<Vec<(String, String)>, errors::ConnectorError> {
+        let timestamp = OffsetDateTime::now_utc().unix_timestamp_nanos() / 1_000_000;
+        let auth: fiserv::FiservAuthType =
+            fiserv::FiservAuthType::try_from(&req.connector_auth_type)?;
+        let api_key = auth.api_key.clone();
+
+        let fiserv_req = self
+            .get_request_body(req)?
+            .ok_or(errors::ConnectorError::RequestEncodingFailed)?;
+        let client_request_id = Uuid::new_v4().to_string();
+        let hmac = self
+            .generate_authorization_signature(auth, &client_request_id, &fiserv_req, timestamp)
+            .change_context(errors::ConnectorError::RequestEncodingFailed)?;
+        let headers = vec![
+            (
+                headers::CONTENT_TYPE.to_string(),
+                types::PaymentsAuthorizeType::get_content_type(self).to_string(),
+            ),
+            ("Client-Request-Id".to_string(), client_request_id),
+            ("Auth-Token-Type".to_string(), "HMAC".to_string()),
+            ("Api-Key".to_string(), api_key),
+            ("Timestamp".to_string(), timestamp.to_string()),
+            ("Authorization".to_string(), hmac),
+        ];
+        Ok(headers)
+    }
+
+    fn get_content_type(&self) -> &'static str {
+        "application/json"
+    }
+
+    fn get_url(
+        &self,
+        _req: &types::PaymentsAuthorizeRouterData,
+        connectors: &settings::Connectors,
+    ) -> CustomResult<String, errors::ConnectorError> {
+        Ok(format!(
+            "{}ch/payments/v1/charges",
+            connectors.fiserv.base_url
+        ))
+    }
+
+    fn get_request_body(
+        &self,
+        req: &types::PaymentsAuthorizeRouterData,
+    ) -> CustomResult<Option<String>, errors::ConnectorError> {
+        let fiserv_req = utils::Encode::<fiserv::FiservPaymentsRequest>::convert_and_encode(req)
+            .change_context(errors::ConnectorError::RequestEncodingFailed)?;
+        Ok(Some(fiserv_req))
+    }
+
+    fn build_request(
+        &self,
+        req: &types::PaymentsAuthorizeRouterData,
+        connectors: &settings::Connectors,
+    ) -> CustomResult<Option<services::Request>, errors::ConnectorError> {
+        let request = Some(
+            services::RequestBuilder::new()
+                .method(services::Method::Post)
+                .url(&types::PaymentsAuthorizeType::get_url(
+                    self, req, connectors,
+                )?)
+                .headers(types::PaymentsAuthorizeType::get_headers(
+                    self, req, connectors,
+                )?)
+                .body(types::PaymentsAuthorizeType::get_request_body(self, req)?)
+                .build(),
+        );
+
+        Ok(request)
+    }
+
+    fn handle_response(
+        &self,
+        data: &types::PaymentsAuthorizeRouterData,
+        res: types::Response,
+    ) -> CustomResult<types::PaymentsAuthorizeRouterData, errors::ConnectorError> {
+        let response: fiserv::FiservPaymentsResponse = res
+            .response
+            .parse_struct("Fiserv PaymentResponse")
+            .change_context(errors::ConnectorError::ResponseDeserializationFailed)?;
+        types::ResponseRouterData {
+            response,
+            data: data.clone(),
+            http_code: res.status_code,
+        }
+        .try_into()
+        .change_context(errors::ConnectorError::ResponseHandlingFailed)
+    }
+
+    fn get_error_response(
+        &self,
+        res: Bytes,
+    ) -> CustomResult<types::ErrorResponse, errors::ConnectorError> {
+        let response: fiserv::ErrorResponse = res
+            .parse_struct("Fiserv ErrorResponse")
+            .change_context(errors::ConnectorError::ResponseDeserializationFailed)?;
+
+        let fiserv::ErrorResponse { error, details } = response;
+
+        let message = match (error, details) {
+            (Some(err), _) => err
+                .iter()
+                .map(|v| v.message.clone())
+                .collect::<Vec<String>>()
+                .join(""),
+            (None, Some(err_details)) => err_details
+                .iter()
+                .map(|v| v.message.clone())
+                .collect::<Vec<String>>()
+                .join(""),
+            (None, None) => consts::NO_ERROR_MESSAGE.to_string(),
+        };
+        Ok(types::ErrorResponse {
+            code: consts::NO_ERROR_CODE.to_string(),
+            message,
+            reason: None,
+        })
+    }
+}
+
+impl api::Refund for Fiserv {}
+impl api::RefundExecute for Fiserv {}
+impl api::RefundSync for Fiserv {}
+
+#[allow(dead_code)]
+impl services::ConnectorIntegration<api::Execute, types::RefundsData, types::RefundsResponseData>
+    for Fiserv
+{
+}
+
+#[allow(dead_code)]
+impl services::ConnectorIntegration<api::RSync, types::RefundsData, types::RefundsResponseData>
+    for Fiserv
+{
+}
+
+#[async_trait::async_trait]
+impl api::IncomingWebhook for Fiserv {
+    fn get_webhook_object_reference_id(
+        &self,
+        _body: &[u8],
+    ) -> CustomResult<String, errors::ConnectorError> {
+        Err(errors::ConnectorError::NotImplemented("fiserv".to_string()).into())
+    }
+
+    fn get_webhook_event_type(
+        &self,
+        _body: &[u8],
+    ) -> CustomResult<api::IncomingWebhookEvent, errors::ConnectorError> {
+        Err(errors::ConnectorError::NotImplemented("fiserv".to_string()).into())
+    }
+
+    fn get_webhook_resource_object(
+        &self,
+        _body: &[u8],
+    ) -> CustomResult<serde_json::Value, errors::ConnectorError> {
+        Err(errors::ConnectorError::NotImplemented("fiserv".to_string()).into())
+    }
+}
+
+impl services::ConnectorRedirectResponse for Fiserv {
+    fn get_flow_type(
+        &self,
+        _query_params: &str,
+    ) -> CustomResult<payments::CallConnectorAction, errors::ConnectorError> {
+        Ok(payments::CallConnectorAction::Trigger)
+    }
+}
diff --git a/crates/router/src/connector/fiserv/transformers.rs b/crates/router/src/connector/fiserv/transformers.rs
new file mode 100644
index 00000000000..a16fdea007a
--- /dev/null
+++ b/crates/router/src/connector/fiserv/transformers.rs
@@ -0,0 +1,343 @@
+use common_utils::ext_traits::ValueExt;
+use error_stack::ResultExt;
+use serde::{Deserialize, Serialize};
+
+use crate::{
+    core::errors,
+    pii::{self, Secret},
+    types::{self, api, storage::enums},
+};
+
+#[derive(Default, Debug, Serialize, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct FiservPaymentsRequest {
+    amount: Amount,
+    source: Source,
+    transaction_details: TransactionDetails,
+    merchant_details: MerchantDetails,
+    transaction_interaction: TransactionInteraction,
+}
+
+#[derive(Default, Debug, Serialize, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct Source {
+    source_type: String,
+    card: CardData,
+}
+
+#[derive(Default, Debug, Serialize, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct CardData {
+    card_data: Secret<String, pii::CardNumber>,
+    expiration_month: Secret<String>,
+    expiration_year: Secret<String>,
+    security_code: Secret<String>,
+}
+
+#[derive(Default, Debug, Serialize, Eq, PartialEq)]
+pub struct Amount {
+    total: i64,
+    currency: String,
+}
+
+#[derive(Default, Debug, Serialize, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct TransactionDetails {
+    capture_flag: bool,
+}
+
+#[derive(Default, Debug, Serialize, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct MerchantDetails {
+    merchant_id: String,
+    terminal_id: String,
+}
+
+#[derive(Default, Debug, Serialize, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct TransactionInteraction {
+    origin: String,
+    eci_indicator: String,
+    pos_condition_code: String,
+}
+
+impl TryFrom<&types::PaymentsAuthorizeRouterData> for FiservPaymentsRequest {
+    type Error = error_stack::Report<errors::ConnectorError>;
+    fn try_from(item: &types::PaymentsAuthorizeRouterData) -> Result<Self, Self::Error> {
+        match item.request.payment_method_data {
+            api::PaymentMethod::Card(ref ccard) => {
+                let auth: FiservAuthType = FiservAuthType::try_from(&item.connector_auth_type)?;
+                let amount = Amount {
+                    total: item.request.amount,
+                    currency: item.request.currency.to_string(),
+                };
+
+                let card = CardData {
+                    card_data: ccard.card_number.clone(),
+                    expiration_month: ccard.card_exp_month.clone(),
+                    expiration_year: ccard.card_exp_year.clone(),
+                    security_code: ccard.card_cvc.clone(),
+                };
+                let source = Source {
+                    source_type: "PaymentCard".to_string(),
+                    card,
+                };
+                let transaction_details = TransactionDetails {
+                    capture_flag: matches!(
+                        item.request.capture_method,
+                        Some(enums::CaptureMethod::Automatic) | None
+                    ),
+                };
+                let metadata = item
+                    .connector_meta_data
+                    .clone()
+                    .ok_or(errors::ConnectorError::RequestEncodingFailed)?;
+                let session: SessionObject = metadata
+                    .parse_value("SessionObject")
+                    .change_context(errors::ConnectorError::RequestEncodingFailed)?;
+
+                let merchant_details = MerchantDetails {
+                    merchant_id: auth.merchant_account,
+                    terminal_id: session.terminal_id,
+                };
+
+                let transaction_interaction = TransactionInteraction {
+                    origin: "ECOM".to_string(), //Payment is being made in online mode, card not present
+                    eci_indicator: "CHANNEL_ENCRYPTED".to_string(), // transaction encryption such as SSL/TLS, but authentication was not performed
+                    pos_condition_code: "CARD_NOT_PRESENT_ECOM".to_string(), //card not present in online transaction
+                };
+                Ok(Self {
+                    amount,
+                    source,
+                    transaction_details,
+                    merchant_details,
+                    transaction_interaction,
+                })
+            }
+            _ => Err(errors::ConnectorError::NotImplemented(
+                "Payment Methods".to_string(),
+            ))?,
+        }
+    }
+}
+
+pub struct FiservAuthType {
+    pub(super) api_key: String,
+    pub(super) merchant_account: String,
+    pub(super) api_secret: String,
+}
+
+impl TryFrom<&types::ConnectorAuthType> for FiservAuthType {
+    type Error = error_stack::Report<errors::ConnectorError>;
+    fn try_from(auth_type: &types::ConnectorAuthType) -> Result<Self, Self::Error> {
+        if let types::ConnectorAuthType::SignatureKey {
+            api_key,
+            key1,
+            api_secret,
+        } = auth_type
+        {
+            Ok(Self {
+                api_key: api_key.to_string(),
+                merchant_account: key1.to_string(),
+                api_secret: api_secret.to_string(),
+            })
+        } else {
+            Err(errors::ConnectorError::FailedToObtainAuthType)?
+        }
+    }
+}
+
+#[derive(Debug, Default, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ErrorResponse {
+    pub details: Option<Vec<ErrorDetails>>,
+    pub error: Option<Vec<ErrorDetails>>,
+}
+
+#[derive(Debug, Default, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ErrorDetails {
+    #[serde(rename = "type")]
+    pub error_type: String,
+    pub code: Option<String>,
+    pub message: String,
+}
+
+#[derive(Debug, Clone, Default, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "UPPERCASE")]
+pub enum FiservPaymentStatus {
+    Succeeded,
+    Failed,
+    Captured,
+    Declined,
+    Voided,
+    Authorized,
+    #[default]
+    Processing,
+}
+
+impl From<FiservPaymentStatus> for enums::AttemptStatus {
+    fn from(item: FiservPaymentStatus) -> Self {
+        match item {
+            FiservPaymentStatus::Captured | FiservPaymentStatus::Succeeded => Self::Charged,
+            FiservPaymentStatus::Declined | FiservPaymentStatus::Failed => Self::Failure,
+            FiservPaymentStatus::Processing => Self::Authorizing,
+            FiservPaymentStatus::Voided => Self::Voided,
+            FiservPaymentStatus::Authorized => Self::Authorized,
+        }
+    }
+}
+
+#[derive(Default, Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct FiservPaymentsResponse {
+    gateway_response: GatewayResponse,
+}
+
+#[derive(Default, Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct GatewayResponse {
+    gateway_transaction_id: String,
+    transaction_state: FiservPaymentStatus,
+    transaction_processing_details: TransactionProcessingDetails,
+}
+
+#[derive(Default, Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct TransactionProcessingDetails {
+    order_id: String,
+    transaction_id: String,
+}
+
+impl<F, T>
+    TryFrom<types::ResponseRouterData<F, FiservPaymentsResponse, T, types::PaymentsResponseData>>
+    for types::RouterData<F, T, types::PaymentsResponseData>
+{
+    type Error = error_stack::Report<errors::ConnectorError>;
+    fn try_from(
+        item: types::ResponseRouterData<F, FiservPaymentsResponse, T, types::PaymentsResponseData>,
+    ) -> Result<Self, Self::Error> {
+        let gateway_resp = item.response.gateway_response;
+
+        Ok(Self {
+            status: gateway_resp.transaction_state.into(),
+            response: Ok(types::PaymentsResponseData::TransactionResponse {
+                resource_id: types::ResponseId::ConnectorTransactionId(
+                    gateway_resp.transaction_processing_details.transaction_id,
+                ),
+                redirection_data: None,
+                redirect: false,
+                mandate_reference: None,
+                connector_metadata: None,
+            }),
+            ..item.data
+        })
+    }
+}
+
+#[derive(Default, Debug, Serialize, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct FiservCaptureRequest {
+    amount: Amount,
+    transaction_details: TransactionDetails,
+    merchant_details: MerchantDetails,
+    reference_transaction_details: ReferenceTransactionDetails,
+}
+
+#[derive(Default, Debug, Serialize, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct ReferenceTransactionDetails {
+    reference_transaction_id: String,
+}
+
+#[derive(Debug, Default, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SessionObject {
+    pub terminal_id: String,
+}
+
+impl TryFrom<&types::PaymentsCaptureRouterData> for FiservCaptureRequest {
+    type Error = error_stack::Report<errors::ConnectorError>;
+    fn try_from(item: &types::PaymentsCaptureRouterData) -> Result<Self, Self::Error> {
+        let auth: FiservAuthType = FiservAuthType::try_from(&item.connector_auth_type)?;
+        let metadata = item
+            .connector_meta_data
+            .clone()
+            .ok_or(errors::ConnectorError::RequestEncodingFailed)?;
+        let session: SessionObject = metadata
+            .parse_value("SessionObject")
+            .change_context(errors::ConnectorError::RequestEncodingFailed)?;
+        let amount = item
+            .request
+            .amount_to_capture
+            .ok_or(errors::ConnectorError::RequestEncodingFailed)?;
+        Ok(Self {
+            amount: Amount {
+                total: amount,
+                currency: item.request.currency.to_string(),
+            },
+            transaction_details: TransactionDetails { capture_flag: true },
+            merchant_details: MerchantDetails {
+                merchant_id: auth.merchant_account,
+                terminal_id: session.terminal_id,
+            },
+            reference_transaction_details: ReferenceTransactionDetails {
+                reference_transaction_id: item.request.connector_transaction_id.to_string(),
+            },
+        })
+    }
+}
+
+#[derive(Default, Debug, Serialize)]
+pub struct FiservRefundRequest {}
+
+impl<F> TryFrom<&types::RefundsRouterData<F>> for FiservRefundRequest {
+    type Error = error_stack::Report<errors::ConnectorError>;
+    fn try_from(_item: &types::RefundsRouterData<F>) -> Result<Self, Self::Error> {
+        Err(errors::ConnectorError::NotImplemented("fiserv".to_string()).into())
+    }
+}
+
+#[allow(dead_code)]
+#[derive(Debug, Serialize, Default, Deserialize, Clone)]
+pub enum RefundStatus {
+    Succeeded,
+    Failed,
+    #[default]
+    Processing,
+}
+
+impl From<RefundStatus> for enums::RefundStatus {
+    fn from(item: RefundStatus) -> Self {
+        match item {
+            RefundStatus::Succeeded => Self::Success,
+            RefundStatus::Failed => Self::Failure,
+            RefundStatus::Processing => Self::Pending,
+        }
+    }
+}
+
+#[derive(Default, Debug, Clone, Serialize, Deserialize)]
+pub struct RefundResponse {}
+
+impl TryFrom<types::RefundsResponseRouterData<api::Execute, RefundResponse>>
+    for types::RefundsRouterData<api::Execute>
+{
+    type Error = error_stack::Report<errors::ConnectorError>;
+    fn try_from(
+        _item: types::RefundsResponseRouterData<api::Execute, RefundResponse>,
+    ) -> Result<Self, Self::Error> {
+        Err(errors::ConnectorError::NotImplemented("fiserv".to_string()).into())
+    }
+}
+
+impl TryFrom<types::RefundsResponseRouterData<api::RSync, RefundResponse>>
+    for types::RefundsRouterData<api::RSync>
+{
+    type Error = error_stack::Report<errors::ConnectorError>;
+    fn try_from(
+        _item: types::RefundsResponseRouterData<api::RSync, RefundResponse>,
+    ) -> Result<Self, Self::Error> {
+        Err(errors::ConnectorError::NotImplemented("fiserv".to_string()).into())
+    }
+}
diff --git a/crates/router/src/core/payments/transformers.rs b/crates/router/src/core/payments/transformers.rs
index 89059f6b95f..5845bdaded8 100644
--- a/crates/router/src/core/payments/transformers.rs
+++ b/crates/router/src/core/payments/transformers.rs
@@ -455,11 +455,11 @@ impl<F: Clone> TryFrom<PaymentData<F>> for types::PaymentsCaptureData {
     fn try_from(payment_data: PaymentData<F>) -> Result<Self, Self::Error> {
         Ok(Self {
             amount_to_capture: payment_data.payment_attempt.amount_to_capture,
+            currency: payment_data.currency,
             connector_transaction_id: payment_data
                 .payment_attempt
                 .connector_transaction_id
                 .ok_or(errors::ApiErrorResponse::MerchantConnectorAccountNotFound)?,
-            currency: payment_data.currency,
             amount: payment_data.amount.into(),
         })
     }
diff --git a/crates/router/src/types.rs b/crates/router/src/types.rs
index d4c1cc0e3bd..37143542a0c 100644
--- a/crates/router/src/types.rs
+++ b/crates/router/src/types.rs
@@ -112,8 +112,8 @@ pub struct PaymentsAuthorizeData {
 #[derive(Debug, Clone)]
 pub struct PaymentsCaptureData {
     pub amount_to_capture: Option<i64>,
-    pub connector_transaction_id: String,
     pub currency: storage_enums::Currency,
+    pub connector_transaction_id: String,
     pub amount: i64,
 }
 
diff --git a/crates/router/src/types/api.rs b/crates/router/src/types/api.rs
index f9feb7e9442..a14ad31c1d6 100644
--- a/crates/router/src/types/api.rs
+++ b/crates/router/src/types/api.rs
@@ -139,19 +139,20 @@ impl ConnectorData {
         connector_name: &str,
     ) -> CustomResult<BoxedConnector, errors::ApiErrorResponse> {
         match connector_name {
-            "stripe" => Ok(Box::new(&connector::Stripe)),
-            "adyen" => Ok(Box::new(&connector::Adyen)),
             "aci" => Ok(Box::new(&connector::Aci)),
-            "checkout" => Ok(Box::new(&connector::Checkout)),
+            "adyen" => Ok(Box::new(&connector::Adyen)),
+            "applepay" => Ok(Box::new(&connector::Applepay)),
             "authorizedotnet" => Ok(Box::new(&connector::Authorizedotnet)),
             "braintree" => Ok(Box::new(&connector::Braintree)),
-            "klarna" => Ok(Box::new(&connector::Klarna)),
-            "applepay" => Ok(Box::new(&connector::Applepay)),
+            "checkout" => Ok(Box::new(&connector::Checkout)),
             "cybersource" => Ok(Box::new(&connector::Cybersource)),
+            "fiserv" => Ok(Box::new(&connector::Fiserv)),
+            "globalpay" => Ok(Box::new(&connector::Globalpay)),
+            "klarna" => Ok(Box::new(&connector::Klarna)),
+            "payu" => Ok(Box::new(&connector::Payu)),
             "shift4" => Ok(Box::new(&connector::Shift4)),
+            "stripe" => Ok(Box::new(&connector::Stripe)),
             "worldpay" => Ok(Box::new(&connector::Worldpay)),
-            "payu" => Ok(Box::new(&connector::Payu)),
-            "globalpay" => Ok(Box::new(&connector::Globalpay)),
             _ => Err(report!(errors::ConnectorError::InvalidConnectorName)
                 .attach_printable(format!("invalid connector name: {connector_name}")))
             .change_context(errors::ApiErrorResponse::InternalServerError),
diff --git a/crates/router/tests/connectors/connector_auth.rs b/crates/router/tests/connectors/connector_auth.rs
index 86683b0f7a6..2237f0994d2 100644
--- a/crates/router/tests/connectors/connector_auth.rs
+++ b/crates/router/tests/connectors/connector_auth.rs
@@ -6,6 +6,7 @@ pub(crate) struct ConnectorAuthentication {
     pub aci: Option<BodyKey>,
     pub authorizedotnet: Option<BodyKey>,
     pub checkout: Option<BodyKey>,
+    pub fiserv: Option<SignatureKey>,
     pub globalpay: Option<HeaderKey>,
     pub payu: Option<BodyKey>,
     pub shift4: Option<HeaderKey>,
@@ -50,3 +51,20 @@ impl From<BodyKey> for ConnectorAuthType {
         }
     }
 }
+
+#[derive(Debug, Deserialize, Clone)]
+pub(crate) struct SignatureKey {
+    pub api_key: String,
+    pub key1: String,
+    pub api_secret: String,
+}
+
+impl From<SignatureKey> for ConnectorAuthType {
+    fn from(key: SignatureKey) -> Self {
+        Self::SignatureKey {
+            api_key: key.api_key,
+            key1: key.key1,
+            api_secret: key.api_secret,
+        }
+    }
+}
diff --git a/crates/router/tests/connectors/fiserv.rs b/crates/router/tests/connectors/fiserv.rs
new file mode 100644
index 00000000000..56092b8687b
--- /dev/null
+++ b/crates/router/tests/connectors/fiserv.rs
@@ -0,0 +1,129 @@
+use masking::Secret;
+use router::types::{self, api, storage::enums};
+use serde_json::json;
+
+use crate::{
+    connector_auth,
+    utils::{self, ConnectorActions},
+};
+
+struct Fiserv;
+impl ConnectorActions for Fiserv {}
+
+impl utils::Connector for Fiserv {
+    fn get_data(&self) -> types::api::ConnectorData {
+        use router::connector::Fiserv;
+        types::api::ConnectorData {
+            connector: Box::new(&Fiserv),
+            connector_name: types::Connector::Fiserv,
+            get_token: types::api::GetToken::Connector,
+        }
+    }
+
+    fn get_auth_token(&self) -> types::ConnectorAuthType {
+        types::ConnectorAuthType::from(
+            connector_auth::ConnectorAuthentication::new()
+                .fiserv
+                .expect("Missing connector authentication configuration"),
+        )
+    }
+
+    fn get_name(&self) -> String {
+        "fiserv".to_string()
+    }
+
+    fn get_connector_meta(&self) -> Option<serde_json::Value> {
+        Some(json!({"terminalId": "10000001"}))
+    }
+}
+
+#[actix_web::test]
+async fn should_only_authorize_payment() {
+    let response = Fiserv {}
+        .authorize_payment(
+            Some(types::PaymentsAuthorizeData {
+                payment_method_data: types::api::PaymentMethod::Card(api::CCard {
+                    card_number: Secret::new("4005550000000019".to_string()),
+                    card_exp_month: Secret::new("02".to_string()),
+                    card_exp_year: Secret::new("2035".to_string()),
+                    card_holder_name: Secret::new("John Doe".to_string()),
+                    card_cvc: Secret::new("123".to_string()),
+                }),
+                capture_method: Some(storage_models::enums::CaptureMethod::Manual),
+                ..utils::PaymentAuthorizeType::default().0
+            }),
+            None,
+        )
+        .await;
+    assert_eq!(response.status, enums::AttemptStatus::Authorized);
+}
+
+#[actix_web::test]
+async fn should_authorize_and_capture_payment() {
+    let response = Fiserv {}
+        .make_payment(
+            Some(types::PaymentsAuthorizeData {
+                payment_method_data: types::api::PaymentMethod::Card(api::CCard {
+                    card_number: Secret::new("4005550000000019".to_string()),
+                    card_exp_month: Secret::new("02".to_string()),
+                    card_exp_year: Secret::new("2035".to_string()),
+                    card_holder_name: Secret::new("John Doe".to_string()),
+                    card_cvc: Secret::new("123".to_string()),
+                }),
+                ..utils::PaymentAuthorizeType::default().0
+            }),
+            None,
+        )
+        .await;
+    assert_eq!(response.status, enums::AttemptStatus::Charged);
+}
+
+// You get a service declined for Payment Capture, look into it from merchant dashboard
+/*
+#[actix_web::test]
+async fn should_capture_already_authorized_payment() {
+    let connector = Fiserv {};
+    let authorize_response = connector.authorize_payment(None, None).await;
+    assert_eq!(authorize_response.status, enums::AttemptStatus::Authorized);
+    let txn_id = utils::get_connector_transaction_id(authorize_response);
+    let response: OptionFuture<_> = txn_id
+        .map(|transaction_id| async move {
+            connector.capture_payment(transaction_id, None, None).await.status
+        })
+        .into();
+    assert_eq!(response.await, Some(enums::AttemptStatus::Charged));
+}
+
+#[actix_web::test]
+async fn should_fail_payment_for_incorrect_cvc() {
+    let response = Fiserv {}.make_payment(Some(types::PaymentsAuthorizeData {
+            payment_method_data: types::api::PaymentMethod::Card(api::CCard {
+                card_number: Secret::new("4024007134364842".to_string()),
+                ..utils::CCardType::default().0
+            }),
+            ..utils::PaymentAuthorizeType::default().0
+        }), None)
+        .await;
+    let x = response.response.unwrap_err();
+    assert_eq!(
+        x.message,
+        "The card's security code failed verification.".to_string(),
+    );
+}
+
+#[actix_web::test]
+async fn should_refund_succeeded_payment() {
+    let connector = Fiserv {};
+    //make a successful payment
+    let response = connector.make_payment(None, None).await;
+
+    //try refund for previous payment
+    if let Some(transaction_id) = utils::get_connector_transaction_id(response) {
+        let response = connector.refund_payment(transaction_id, None, None).await;
+        assert_eq!(
+            response.response.unwrap().refund_status,
+            enums::RefundStatus::Success,
+        );
+    }
+}
+*/
diff --git a/crates/router/tests/connectors/main.rs b/crates/router/tests/connectors/main.rs
index b0b44c89cba..3d5af329ed7 100644
--- a/crates/router/tests/connectors/main.rs
+++ b/crates/router/tests/connectors/main.rs
@@ -4,6 +4,7 @@ mod aci;
 mod authorizedotnet;
 mod checkout;
 mod connector_auth;
+mod fiserv;
 mod globalpay;
 mod payu;
 mod shift4;
diff --git a/crates/router/tests/connectors/sample_auth.toml b/crates/router/tests/connectors/sample_auth.toml
index a8fe5dffe2e..463e6460b54 100644
--- a/crates/router/tests/connectors/sample_auth.toml
+++ b/crates/router/tests/connectors/sample_auth.toml
@@ -25,3 +25,9 @@ key1 = "MerchantPosId"
 
 [globalpay]
 api_key = "Bearer MyApiKey"
+
+[fiserv]
+api_key = "MyApiKey"
+key1 = "MerchantID"
+api_secret = "MySecretKey"
+
diff --git a/crates/router/tests/connectors/utils.rs b/crates/router/tests/connectors/utils.rs
index 650eafd7bf0..99c14b65df0 100644
--- a/crates/router/tests/connectors/utils.rs
+++ b/crates/router/tests/connectors/utils.rs
@@ -78,8 +78,8 @@ pub trait ConnectorActions: Connector {
         let request = self.generate_data(
             payment_data.unwrap_or(types::PaymentsCaptureData {
                 amount_to_capture: Some(100),
-                connector_transaction_id: transaction_id,
                 currency: enums::Currency::USD,
+                connector_transaction_id: transaction_id,
                 amount: 100,
             }),
             payment_info,