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 just have a single body part like:

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}

Note that the Content-Transfer-Encoding can be 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, like base64, the JSON must be encoded as UTF-8.

Valid nested multipart/alternative in multipart/related

If the reaction is to a message that had inline attachments, it's possible to generate a message with a multipart/related body part that contains the attachments plus a multipart/alternative part like 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--

(Note that the multipart/related body part should have other fields as specified by RFC2387 but those are irrelevant for determining 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 ❤ emoji is missing between the two zero-width joiner (ZWJ) characters. Note that the = character at the end of the first content line represents a soft line break in the 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}