Email reaction examples

Here are several samples of valid and invalid email reaction messages.

Valid multipart/alternative

Email reactions usually have three parts:

  • text/plain: the plain text version of the message.
  • text/vnd.google.email-reaction+json: the reaction part.
  • text/html: the HTML version of the message.

Here's an example:

From: test@google.com
Message-ID: <884457408.1.1697791227669@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: multipart/alternative;
        boundary="----=_Part_0_2012232625.1697791227635"

------=_Part_0_2012232625.1697791227635
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Text body content
------=_Part_0_2012232625.1697791227635
Content-Type: text/vnd.google.email-reaction+json; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

{"emoji":"=F0=9F=99=83","version":1}
------=_Part_0_2012232625.1697791227635
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<h1>HTML body content</h1>
------=_Part_0_2012232625.1697791227635--

Single valid body part

Email reactions can also contain a single body part:

From: test+no-reply@google.com
Message-ID: <940553268.0.1697791227697@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: text/vnd.google.email-reaction+json; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

{"emoji":"=F0=9F=99=83","version":1}

The Content-Transfer-Encoding header can use any standard encoding:

From: test+no-reply@google.com
Message-ID: <940553268.0.1697791227697@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: text/vnd.google.email-reaction+json
Content-Transfer-Encoding: base64

ewogICJlbW9qaSI6ICLwn46JIiwKICAidmVyc2lvbiI6IDEKfQ==

For binary encodings, such as base64, the JSON must be encoded as UTF-8.

Valid nested multipart/alternative in multipart/related

If the reaction is to a message with inline attachments, you can generate a message with a multipart/related body part that contains the attachments plus a multipart/alternative part, as shown in the previous example.

From: test@google.com
Message-ID: <913190639.2.1697793303663@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: multipart/related;
        boundary="----=_Part_0_2012232625.1697793303618"

------=_Part_0_2012232625.1697793303618
Content-Type: multipart/alternative;
        boundary="----=_Part_1_984213526.1697793303621"

------=_Part_1_984213526.1697793303621
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Text body content
------=_Part_1_984213526.1697793303621
Content-Type: text/vnd.google.email-reaction+json
Content-Transfer-Encoding: base64

ewogICJlbW9qaSI6ICLwn46JIiwKICAidmVyc2lvbiI6IDEKfQ==
------=_Part_1_984213526.1697793303621
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<h1>HTML body content</h1>
------=_Part_1_984213526.1697793303621--

------=_Part_0_2012232625.1697793303618
Content-Type: image/png
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="1x1.png"

iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEUAAACnej3aAAAAAXRSTlMA
QObYZgAAAApJREFUCNdjYAAAAAIAAeIhvDMAAAAASUVORK5CYII=
------=_Part_0_2012232625.1697793303618--

The multipart/related body part should include other fields specified by RFC 2387, but those fields aren't required to determine whether an email reaction is valid.

Invalid JSON format

The following reaction is invalid because the JSON is missing the closing brace:

From: test+no-reply@google.com
Message-ID: <940553268.0.1697791227697@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: text/vnd.google.email-reaction+json; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

{"emoji":"=F0=9F=99=83","version":1

The following reaction is invalid because the JSON has a trailing comma:

From: test+no-reply@google.com
Message-ID: <940553268.0.1697791227697@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: text/vnd.google.email-reaction+json; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

{"emoji":"=F0=9F=99=83","version":1,}

Invalid version field

The following reaction is invalid because it's missing the version field:

From: test+no-reply@google.com
Message-ID: <940553268.0.1697791227697@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: text/vnd.google.email-reaction+json; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

{"emoji":"=F0=9F=99=83"}

The following reaction is invalid because the version field isn't 1:

From: test+no-reply@google.com
Message-ID: <940553268.0.1697791227697@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: text/vnd.google.email-reaction+json; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

{"emoji":"=F0=9F=99=83","version":2}

Invalid emoji field

The following reaction is invalid because the emoji field is empty:

From: test+no-reply@google.com
Message-ID: <940553268.0.1697791227697@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: text/vnd.google.email-reaction+json; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

{"emoji":"","version":1}

The following reaction is invalid because the emoji field doesn't contain a valid emoji:

From: test+no-reply@google.com
Message-ID: <940553268.0.1697791227697@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: text/vnd.google.email-reaction+json; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

{"emoji":"A","version":1}

The following reaction is invalid because the red heart emoji (❤) is missing between the two zero-width joiner (ZWJ) characters. The = character at the end of the first content line represents a soft line break in Quoted-Printable encoding:

From: test+no-reply@google.com
Message-ID: <940553268.0.1697791227697@mail.google.com>
Subject: subject
MIME-Version: 1.0
In-Reply-To: <2938749223.1.39847234@mail.google.com>
Content-Type: text/vnd.google.email-reaction+json; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

{"emoji":"=F0=9F=91=A9=F0=9F=8F=BC=E2=80=8D=E2=80=8D=F0=9F=91=A8=F0=9F=8F=BE",=
"version":1}